فهرست مطالب

بوم شناسی کشاورزی - سال یازدهم شماره 1 (بهار 1398)
  • سال یازدهم شماره 1 (بهار 1398)
  • تاریخ انتشار: 1398/04/26
  • تعداد عناوین: 23
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  • عبداله ملافیلابی*، محمد رضا گزیکی نژاد صفحات 1-15
    این آزمایش با هدف بررسی اثر تراکم بوته و محلول پاشی برگی بر رشد، عملکرد و اجزای عملکرد گیاه دارویی خاکشیر شیرین (Descurainia sophia L.)، به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی در سال زراعی 96-1395 در مزرعه تحقیقاتی دانشگاه آزاد اسلامی واحد تربت جام اجرا شد. فاکتور های آزمایش شامل سه تراکم بوته (10، 20 و40 بوته در مترمربع) و محلول پاشی با کود کامل (غلظت پنج در هزار) در سه مرحله سبزینه ای، قبل از مرحله گلدهی و شروع دانه بندی و شاهد بود. صفات مورد مطالعه شامل وزن تر و خشک اندام های هوایی، تعداد شاخه جانبی در بوته، وزن هزار دانه و عملکرد بذر، عملکرد بیولوژیک و شاخص برداشت بودند. نتایج نشان داد که  اثر ساده تراکم بوته بر تعداد شاخه جانبی و شاخص برداشت خاکشیر شیرین معنی دار (05/0≥p) بود. اثر ساده محلول پاشی برگی بر تعداد شاخه جانبی و وزن هزار دانه معنی دار (05/0≥p) بود. همچنین اثر متقابل تراکم بوته و محلول پاشی برگی بر تعداد شاخه جانبی در بوته، وزن خشک اندام های هوایی، عملکرد بذر، عملکرد بیولوژیک و شاخص برداشت معنی دار (05/0≥p) بود. بالاترین عملکرد بذر، عملکرد بیولوژیک و وزن خشک اندام های هوایی از تراکم 40 بوته در متر مربع+ محلول پاشی برگی در مرحله شروع دانه بندی به ترتیب با 99، 495 و 396 گرم بر متر مربع حاصل شد. کمترین عملکرد بذر مربوط به تراکم 10 بوته در متر مربع+شاهد با 35 گرم بر متر مربع بود. کمترین مقادیر عملکرد بیولوژیک و وزن خشک اندام های هوایی برای تراکم 20 بوته در متر مربع+ محلول پاشی در مرحله شروع دانه بندی به ترتیب با 168 و 126 گرم بر متر مربع مشاهده شد. بالاترین ضریب همبستگی مربوط به عملکرد بیولوژیک با وزن خشک اندام های هوایی (**97/0r=) بود. بر این اساس، به نظر می رسد انتخاب تراکم مناسب و محلول پاشی برگی راهکاری مدیریتی برای دستیابی پایدار به عملکرد بذر گیاه دارویی خاکشیر شیرین به عنوان گونه ای مقاوم برای توسعه کشت در مناطق خشک و نیمه خشک همچون خراسان می باشد.
    کلیدواژگان: کود کامل، مرحله شروع دانه بندی، وزن خشک اندام های هوایی، عملکرد بذر
  • رضا صدرآبادی حقیقی، حبیب شیخ جنبدواز، عبداله ملافیلابی* صفحات 17-31
    به منظور بررسی تاثیر کاربرد دو نوع کود زیستی Aa40 و Humus-S و غلظت های آن ها بر عملکرد و اجزای عملکرد گل و بنه زعفران (Crocus sativus L.)، آزمایشی به صورت فاکتوریل دو عاملی در قالب طرح بلوک های کامل تصادفی در سه تکرار در منطقه کارده طی سال های 1395 تا 1396 انجام شد. عامل اول شامل دو نوع کود زیستی Humus-S و کود Aa40 و عامل دوم شامل غلظت های صفر، 1، 5/1، 2 و 5/2 در هزار این دو نوع کود به صورت محلول پاشی در دو مرحله بود. صفات مورد مطالعه شامل وزن تر گل، وزن تر و خشک کلاله، وزن تر و خشک گل بدون کلاله، وزن تر و خشک برگ، وزن بنه های دختری، تعداد گل، تعداد بنه های دختری در گروه های وزنی 5-1/0، 10-1/5، 15-1/10 و بیش از 15 گرم بودند. نتایج نشان داد که غلظت کود تاثیر معنی داری بر اکثر مولفه های عملکردی بنه و گل زعفران داشت. همچنین نوع کود زیستی تاثیر معنی داری بر عملکرد زعفران نداشت. اثر متقابل کود مصرفی و غلظت تنها بر وزن تر برگ تاثیر معنی داری داشت. بیشترین وزن خشک کلاله و وزن خشک بنه های دختری برای غلظت 5/2 در هزار با 98/1239 و 4955 گرم بر متر مربع بدست آمد و کمترین مقادیر به شاهد به ترتیب با 56/930 و 4085 گرم بر متر مربع اختصاص داشت. بالاترین و پایین ترین تعداد بنه های دختری به ترتیب برای غلظت 2 در هزار و شاهد با 415 و 33/380 بنه در متر مربع مشاهده شد. با توجه به یافته های تحقیق می توان نتیجه گرفت با افزایش غلظت کودهای زیستی تا حد بهینه می توان عملکرد زعفران را بهبود داد. درضمن کاربرد کودهای زیستی جایگزین مناسبی بجای کودهای شیمیایی از لحاظ بهبود عملکرد و کاهش آلودگی های زیست محیطی می باشد.
    کلیدواژگان: بهره وری انرژی، سوخت فسیلی، کارایی مصرف انرژی، عملیات زراعی
  • شجاعت زارع، علی اکبر مویدی* صفحات 33-51
    این مطالعه با هدف ارزیابی اقتصادی دو تناوب زراعی و در قالب کشاورزی حفاظتی انجام شد. آزمایش‏های هر تناوب زراعی با استفاده از طرح کرت‏های خرد شده در قالب طرح بلوک های کامل تصادفی و با سه تکرار، در ایستگاه تحقیقات کشاورزی و منابع طبیعی استان خراسان رضوی در 5 سال متوالی انجام شد. تیمارهای آزمایش، شیوه‏های مختلف خاک ورزی در سه سطح شامل: شیوه متداول خاک‏ورز ی (شخم + دیسک + تسطیح + کاشت با بذرکار)، شخم کاهش یافته (چیزل پکر یا دیسک سبک + کاشت با بذرکار) و بدون شخم (کاشت مستقیم با بذرکار) در کرت های اصلی و مدیریت بقایای گیاهی در سه سطح بدون بقایا، حفظ 30% بقایا و حفظ 60% بقایای محصولات مختلف درکرت‏های فرعی قرار داده شدند. سیستم تناوب زراعی رایج این منطقه شامل گندم (Triticum aestivum L.) - ذرت (Zea mays L.) -گندم- خربزه (Cucumis melo L.)- گندم و سیستم تناوب زراعی پیشنهادی یا پایدار شامل گندم- کلزا (Brassica napus L.)-گندم-شبدر ایرانی (Trifolium resupinatum L.)- گوجه‏فرنگی (Solanum lycopersicum L.)- گندم هر کدام بصورت جداگانه با استفاده از روش بودجه بندی جزئی مورد بررسی اقتصادی قرار گرفت. اطلاعات مورد نیاز شامل میزان و ارزش نهاده‏های استفاده شده در مراحل کاشت، داشت، برداشت و محصولات حاصل شامل محصول اصلی و کاه و کلش بود. نتایج نشان داد که منفعت خالص تناوب پایدار در مجموع، بیش از دو برابر منفعت خالص تناوب رایج است. در تناوب زراعی رایج تیمار شخم متداول با حفظ 30% بقایای گیاهی با منفعت خالص 246371580 ریال و نرخ بازده 437 درصد بیشترین منفعت خالص و نرخ بازده را داشت. در صورتی که در نظام تناوب زراعی پایدار تیمار بدون شخم و بدون بقایا با منفعت خالص 450020790 ریال بیشترین درآمد و کمترین هزینه را داشت. خالص ارزش تولید هر متر مکعب آب در تناوب پایدار  56159 ریال و در تناوب جاری 27157 ریال بود. این نتایج نشان داد، تناوب زراعی که کشاورزان استفاده می‏کنند از نظر اقتصادی توجیهی برای بکارگیری کشاورزی حفاظتی ندارد، اما اگر تناوب زراعی تغییر کند در آن صورت کشاورزی حفاظتی در قسمت حذف ماشین‏آلات آماده سازی زمین، اقتصادی است، اما تمایلی به حفظ بقایا ندارد.
    کلیدواژگان: بودجه بندی جزئی، کلزا، گندم، منفعت خالص، نرخ بازده
  • محمد تقی فیض بخش*، محمد علی دری، نصیبه رضوان طلب صفحات 53-68
    در سال های اخیر ارزیابی انرژی ورودی و خروجی و پتانسیل گرمایش جهانی در بین محققان بخش کشاورزی جایگاه ویژه ای پیدا کرده است. جهت انجام این بررسی از طریق مصاحبه با کشاورزان مختلف، 95 کشاورز تولید کننده سیب زمینی (Solanum tuberosum L.) در استان گلستان و در سال زراعی 96-1395 انتخاب گردید. اطلاعات مربوط به بکارگیری ماشین آلات، نهاده های ورودی شامل غده بذری، کود، سوخت فسیلی، الکتریسیته، آب آبیاری و سموم بوسیله ی پرسشنامه جمع آوری شد. سپس میزان مصرف سوخت، میزان انرژی ورودی و خروجی، شاخص های ارزیابی انرژی و پتانسیل گرمایش جهانی ناشی از انتشار گازهای گلخانه ای بر حسب معادل دی اکسیدکربن محاسبه شد. نتایج نشان داد که کل میزان انرژی ورودی و خروجی  به مزارع سیب زمینی به ترتیب برابر 8/30 و 2/79 گیگاژول در هکتار بود. همچنین بیشترین انرژی ورودی مستقیم در مزارع سیب زمینی مربوط به مصرف سوخت می باشد و نیز در بخش انرژی ورودی غیرمستقیم بیشترین میزان مربوط به کود نیتروژن به دست آمد. نسبت انرژی خروجی به ورودی، بهره وری انرژی و انرژی ویژه به ترتیب برابر 13/2، 71/0 (کیلوگرم بر مگاژول) و 4/1 (مگاژول بر کیلوگرم) محاسبه شد. همچنین میزان پتانسیل گرمایش جهانی در مزارع سیب زمینی 22/1616 کیلوگرم معادل دی اکسیدکربن به دست آمد. مصرف کودهای شیمیایی به ویژه کود نیتروژنه و الکتریسیته، بیش از 50 درصد از انتشار گازهای گلخانه ای اختصاص داشت. چون میزان انرژی مصرفی و انتشار گازهای گلخانه ای در بخش مصرف کود نیتروژن در زراعت سیب زمینی زیاد است،  لزوم بررسی و تحقیق جهت کشت های تناوبی و در تناوب با سیب زمینی و همچنین استفاده از گیاهان تثبیت کننده نیتروژن در راستای مدیریت اکولوژیک در مزارع تولید این محصول، آشکار می گردد.
    کلیدواژگان: بهره وری انرژی، سوخت فسیلی، کارایی مصرف انرژی، عملیات زراعی
  • اسماعیل رضائی چیانه*، یحیی رسولی، جلال جلیلیان، مسعود قدسی صفحات 69-85
    این آزمایش به منظور بررسی مقایسه الگوهای مختلف کشت مخلوط ردیفی نخود (Cicer arietinum L.) و جو (Hordeum vulgare L.) تحت تاثیر کودهای زیستی و شیمیایی، به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار و 24 تیمار در مزرعه ای واقع در آذربایجان غربی- شهرستان نقده در سال زراعی 1393- 1392 به اجرا در آمد. عامل اول شش نوع الگوی کاشت شامل کشت خالص نخود، کشت خالص جو، کشت مخلوط 1 ردیف جو+ 1 ردیف نخود، 2 ردیف جو+ 2 ردیف نخود، 4ردیف جو+ 2ردیف نخود و 2 ردیف جو+ 4 ردیف نخود و عامل دوم چهار سطح کود شامل عدم کاربرد کود (شاهد)، 100% کود شیمیایی (NP) ،کود زیستی (ازتو بارور 1+ فسفاته بارور 2) و 50% کود شیمیایی+ کود زیستی بود. نتایج در مورد گیاه نخود نشان داد که بیشترین عمکرد دانه از کشت خالص با 75/220 گرم در متر مربع و کمترین عملکرد دانه با میانگین 91/78 گرم در متر مربع مربوط به الگوی کشت یک ردیف جو+ یک ردیف نخود بود. بین تیمارهای کودی مورد استفاده بیشترین عملکرد دانه و بیولوژیک نخود از تیمار تلفیقی کود شیمیایی+ کود زیستی و کمترین عملکرد از تیمار عدم مصرف کود به دست آمد. نتایج نشان داد که بیشترین عمکرد دانه جو (12/414 گرم در متر مربع) از کشت خالص و کمترین عملکرد دانه (66/206 گرم در متر مربع) مربوط به الگوی کشت یک ردیف جو+ یک ردیف نخود بود. در بررسی تیمارهای کودی بیشترین و کمترین عملکرد دانه و بیولوژیک به ترتیب از تیمار تلفیقی کود شیمیایی+ کود زیستی و شاهد به دست آمد. کشت مخلوط 2 ردیف جو+ 2 ردیف نخود در شرایط کاربرد کود شیمیایی بیشترین (34/1) میزان نسبت برابری زمین کل را در بین الگوهای مختلف کشت مخلوط به خود اختصاص داد که معادل 34 درصد افزایش در بهره وری استفاده از زمین نسبت به کشت خالص دو گونه بود با توجه به اهداف کشاورزی پایدار با هدف حذف یا کاهش قابل ملاحظه مصرف نهاده های شیمیایی، تیمار عدم کاربرد کود و کود دهی تلفیقی برای نسبت 2 ردیف جو+ 2 ردیف نخود مناسب و قابل توجیه است.
    کلیدواژگان: ازتو باکتر، الگوی کاشت، سودوموناس، کشاورزی پایدار، نسبت برابری زمین
  • فرزاد مندنی*، علی بزرگی حسین آباد، محسن سعیدی، علیرضا باقری، حسن حیدری صفحات 87-102
    جبران عنصر نیتروژن از طریق مصرف کودهای شیمیای باعث به هم خوردن تعادل شیمیایی خاک، شستشوی سریع تر آن و آلودگی بیشتر منابع آبی می شود که در نهایت کاهش کارایی مصرف نیتروژن را در پی دارد. به منظور ارزیابی کارایی جذب و مصرف نیتروژن در ارقام گندم، آزمایشی به صورت کرت های خرد شده در قالب طرح پایه بلوک های کامل تصادفی با سه تکرار تحت شرایط آب و هوایی کرمانشاه در سال زراعی 94-1393 اجرا شد. تیمارهای آزمایش شامل چهار سطح کود نیتروژن (90، 180، 300 و 360 کیلوگرم اوره در هکتار) در قالب عامل اصلی و ارقام گندم پارسی، زارع، پیشگام و اروم در قالب عامل فرعی بود. صفات مورد ارزیابی شامل عملکرد ماده خشکل کل، عملکرد دانه، درصد نیتروژن زیست توده و کارایی جذب، تبدیل و مصرف نیتروژن بود. نتایج نشان داد که رقم پیشگام در مقایسه با سایر ارقام از ویژگی های اکوفیزیولوژیک بهتری در شرایط تیمارهای مصرف کود نیتروژن برخوردار بود. صرف نظر از ارقام گندم، با افزایش میزان کاربرد کود اوره از 90 به 360 کیلوگرم در هکتار، عملکرد ماده خشک کل (94/65 درصد) و عملکرد دانه (06/73 درصد) افزایش یافت. رقم پیشگام نسبت به سایر ارقام از عملکرد دانه بیشتری (37/37 درصد) برخوردار بود. بالاترین عملکرد دانه در رقم پیشگام (8950 کیلوگرم در هکتار) در تیمار 360 کیلوگرم اوره در هکتار و پایین ترین آن در رقم اروم (1264 کیلو گرم در هکتار) و شرایط کودی 90 کیلوگرم در هکتار مشاهده شد. نتایج نشان داد بیشترین کارایی جذب نیتروژن در پایین ترین سطح کودی برای رقم زارع (70/0 کیلوگرم نیتروژن بر کیلوگرم نیتروژن مصرف شده+ قابل جذب خاک) و کمترین آن در بالاترین سطح کودی برای رقم اروم (26/0 کیلوگرم نیتروژن بر کیلوگرم نیتروژن مصرف شده+ قابل جذب خاک) بدست آمد. بیشترین کارایی تبدیل نیتروژن در رقم پیشگام (59 کیلوگرم دانه بر کیلوگرم نیتروژن) در شرایط 90 کیلوگرم اوره در هکتار و کمترین آن در رقم اروم (37 کیلوگرم دانه بر کیلوگرم نیتروژن) در شرایط 360 کیلوگرم اوره در هکتار مشاهده شد. رقم پیشگام در شرایط 90 کیلوگرم اوره در هکتار بیشترین (36 کیلوگرم دانه بر کیلوگرم نیتروژن مصرف شده+ قابل جذب خاک) و رقم اروم در شرایط 360 کیلوگرم اوره در هکتار کمترین (10 کیلوگرم دانه بر کیلوگرم نیتروژن مصرف شده+ قابل جذب خاک) کارایی مصرف نیتروژن را داشت.
    کلیدواژگان: ارقام گندم، کارایی تبدیل نیتروژن، کارایی جذب نیتروژن، کارایی مصرف نیتروژن، نیتروژن زیست توده
  • الهه برومند رضازاده، علیرضا کوچکی*، پرویز رضوانی مقدم، مهدی نصیری محلاتی، امیر لکزیان صفحات 103-122
    ترسیب کربن به معنای افزایش دائمی ذخیره کربن در خاک، ماده گیاهی یا آب بوده و خاک به عنوان بزرگ ترین مخزن کربن در بوم نظام های خشکی دنیا، نقش مهمی در چرخه جهانی کربن دارد. هدف این مطالعه، مدل سازی رابطه سرعت تجزیه بقایای گیاهان زراعی با رژیم های رطوبتی خاک و نسبت کربن به نیتروژن بقایا و نیز محاسبه میزان کربن قابل ترسیب در کشت آبی پنج محصول زراعی عمده در ایران بود. به همین منظور تجزیه بقایای گیاهی گندم (Triticum aestivum L.)، ذرت (Zea mays L.)، کلزا (Brassica napus L.)، پنبه (Gossypium herbaceum L.)، سویا (Glycine max L.) در رژیم های مختلف رطوبتی خاک طی 390 روز انکوباسیون مورد مطالعه قرار گرفت و از داده های حاصله برای مدل سازی تجزیه بقایا استفاده گردید. همچنین محاسبه میزان کربن قابل ترسیب در این محصولات در پنج سال زراعی بر اساس عملکرد، شاخص برداشت و نسبت اندام های هوایی به ریشه در سه سناریوی بازگشت کامل بقایا، بازگشت 50 درصد بقایا و حذف کامل بقایای اندام های هوایی و سه سناریوی رطوبتی 100، 60 و 30 درصد ظرفیت مزرعه انجام شد. مقایسه میزان کربن قابل ترسیب در استان های مختلف نشان داد که در کشت گندم: استان های کرمانشاه و سیستان و بلوچستان، ذرت: قزوین و خراسان جنوبی، کلزا: اصفهان و بوشهر، پنبه: آذربایجان شرقی و هرمزگان، سویا: اردبیل و آذربایجان شرقی به ترتیب بیشترین و کمترین مقدار کربن قابل ترسیب را دارا بودند. با افزایش میزان رطوبت از 30 به 60 و 100 درصد ظرفیت مزرعه و همچنین با کاهش درصد برگشت بقایا به خاک از 100 به 50 درصد و حذف کامل بقایا، میزان کربن قابل ترسیب در خاک همه محصولات مورد مطالعه کاهش یافت. در بین محصولات مورد مطالعه، ذرت و سویا به ترتیب از بالاترین و پایین ترین میزان کربن قابل ترسیب برخوردار بودند. همچنین، در بین استان های مختلف از نظر مجموع کربن قابل ترسیب محصولات مورد مطالعه، استان اردبیل بیشترین و استان سیستان و بلوچستان کمترین مقدار کربن قابل ترسیب در خاک را دارا بودند.
    کلیدواژگان: بازگشت بقایا، درصد تجزیه، رطوبت خاک
  • ویدا ورناصری قندعلی، پرویز رضوانی مقدم*، سرور خرم دل صفحات 123-135
    به منظور بررسی اثر مقادیر مختلف آب آبیاری و مدیریت تلفیقی کودهای آلی و شیمیایی بر عملکرد و اجزاء عملکرد دانه گیاه علف قناری (Phalaris canariensis L.)، آزمایشی به صورت کرت های خرد شده در قالب طرح پایه بلوک های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در سال زراعی 93-1392 اجرا شد. رژیم های مختلف آبیاری در سه سطح (60، 80 و 100 درصد نیاز آبی) در کرت های اصلی و تیمار های کودی در شش سطح (کود شیمیایی (200 کیلوگرم در هکتار از منبع اوره و 150 کیلوگرم در هکتار از منبع سوپر فسفات تریپل)، کود ورمی کمپوست (6 تن در هکتار)، کود دامی (30 تن در هکتار)، کود شیمیایی+کود ورمی کمپوست، کود شیمیایی+کود دامی و شاهد) در کرت های فرعی قرار گرفتند. نتایج آزمایش نشان داد سطوح مختلف آب آبیاری اثر معنی داری بر روی تمامی صفات مورد بررسی به جز شاخص برداشت داشت. ارتفاع، تعداد پنجه، تعداد سنبله، تعداد دانه و وزن دانه در بوته، عملکرد دانه و عملکرد بیولوژیک، پروتئین دانه و عملکرد پروتئین دانه به طور معنی داری تحت تاثیر تیمار های کودی قرار گرفتند. اثر متقابل رژیم های مختلف آبیاری و تیمار های کودی اثر معنی داری بر صفات ارتفاع بوته، تعداد پنجه در بوته داشت. بیشترین ارتفاع بوته در تیمار آبیاری 80 درصد نیاز آبی + کود ورمی کمپوست و بیشترین تعداد پنجه در بوته در تیمار آبیاری 100 درصد نیاز آبی+کود ورمی کمپوست مشاهده شد. همچنین در تیمار آبیاری100 درصد نیاز آبی و 80 درصد نیاز آبی بیشترین تعداد دانه در بوته و بیشترین عملکرد بیولوژیک مشاهده شد. تعداد دانه در بوته و عملکرد بیولوژیک در تیمار مصرف کود دامی و کود ورمی کمپوست بیشترین مقدار را دارا بودند. تیمار های کود دامی و ورمی کمپوست نسبت به تیمار کود شیمیایی و شاهد عملکرد بهتری داشتند. در مجموع اکثر صفات مورد مطالعه تیمار آبیاری 100 درصد نیاز آبی تفاوت معنی داری با آبیاری 80 درصد نیاز آبی نداشت و مصرف کود آلی نیز تاثیر مناسب تری بر رشد و عملکرد گیاه بر جای گذاشت.
    کلیدواژگان: عملکرد بیولوژیک، کود دامی، کود ورمی کمپوست، مدیریت تلفیقی عناصر غذایی
  • علیرضا کوچکی*، مهدی نصیری محلاتی، افسانه امین غفوری، منصوره محلوجی راد صفحات 137-153
    به منظور تفکیک سهم عوامل به نژادی و به زراعی و ارزیابی روند تغییرات آنها داده های تولید، سطح زیر کشت و عملکرد گندم (.Triticum aestivum L) آب کشور در طی دوره 40 ساله 90-1350 مورد تجزیه و تحلیل قرار گرفت. میزان تولید گندم در طی این دوره با متوسط رشد سالانه حدود 8 درصد 25/3 برابر شده درحالی که میانگین رشد سطح زیر کشت تا پایان دهه 70 در حدود 8/2 درصد در سال بوده و در طی دهه 80 بطور متوسط سالانه 1 درصد کاهش یافته است. عملکرد گندم نیز بطور متوسط سالانه 58 کیلوگرم در هکتار (5/3 درصد در سال) افزایش داشته است البته نتایج نشان داد که نوسان سالانه آب و هوایی در طی دوره تحت بررسی باعث شده تا نرخ رشد عملکرد 21 درصد کمتر از مقدار قابل حصول آن باشد. در طی این دوره 40 ساله میانگین سهم عملکرد و سطح زیر کشت در تولید به ترتیب 56 و 44 درصد بوده و برآورد می شود که در دهه 90 سهم عملکرد تا 70 درصد افزایش یابد. پتانسیل ژنتیکی عملکرد ارقام گندم در فاصله سال های 90-1347 سالانه در حدود 57 کیلوگرم در هکتار افزایش یافته که معادل 18/1 درصد در سال می باشد. بر اساس نتایج این تحقیق در طی دوره تحت بررسی 8/34 درصد از رشد سالانه عملکرد گندم آبی کشور مربوط به عوامل به نژادی (اصلاح ارقام) و بقیه مربوط به عملیات به زراعی بوده است. سهم کودهای شیمیایی نیتروژنی و فسفره در رشد عملکرد گندم به ترتیب 4/25 و 8/8 درصد برآورد شد و سایر عملیات به زراعی سهمی معادل 31 درصد در افزایش سالانه عملکرد گندم کشور داشتند. البته سهم عوامل به نژادی و به زراعی در طی این دوره 40 ساله متغیر بوده و بالاترین سهم عوامل ژنتیکی و کودهای شیمیایی در عملکرد مربوط به دهه 70 می باشد.
    کلیدواژگان: آنالیز روند، بازده ژنتیکی، پتانسیل ژنتیکی، شاخص اصلاح ارقام
  • مهدی نصیری محلاتی، علیرضا کوچکی*، آرش قلعه گلاب بهبهانی، آگرین داوری، شهاب الدین معین الدینی صفحات 155-170
    دو فاکتور مهم حفاظت از تنوع زیستی کمی سازی و پایش مداوم آن می‏باشد. در این راستا استفاده از شاخص‏های رایج تنوع زیستی مانند شاخص تنوع شانون و سیمپسون به تنهایی نمی‏تواند تغییرات ایجاد شده در تنوع زیستی را از تمامی جوانب بررسی نماید. به همین جهت استفاده همزمان از شاخص‏های رایج تنوع زیستی و شاخص‏های عدم دستخوردگی می‏تواند راه حلی مناسب برای شناخت دقیق‏تر این تغییرات در پراکنش جمعیتی گونه‏ها و یا تعداد گونه‏های حاضر درون یک بوم نظام باشد. هدف از انجام این مطالعه بررسی و ارزیابی طولانی مدت تنوع زیستی کشاورزی با استفاده از دو گروه شاخص رایج تنوع زیستی و عدم دستخوردگی در بوم نظام‏های زراعی سه استان خراسان شمالی، جنوبی و رضوی با استفاده از داده‏های طولانی مدت سطح زیر کشت شهرستان‏های استان‏ در بازه زمانی 1983 الی 2008 میلادی (1362-1387) بود. نتایج حاصل از برآورد دو شاخص غنای گونه‏ای و شاخص تنوع شانون روند رو به رشد تنوع زیستی کشاورزی را در اکثر مناطق استان نشان داد، اگر چه شاخص تنوع شانون روند رو به کاهش را در برخی از شهرستان‏های این استان‏ها مانند تربت حیدریه، فاروج و جاجرم نشان داد و از سوی دیگر، نتایج حاصل از برآورد شاخص‏ عدم دستخوردگی روند رو به کاهش را نسبت به پنج ساله مبنا (طی سال های 1983-1988 میلادی) نشان داد، از این نتایج استنباط می گردد که الگوی کشت گونه‏های زراعی در این مناطق تغییر یافته و برخی از گونه‏های بومی و قدیمی توسط گونه‏های جدیدالورود جایگزین شده‏اند و این امر سبب شده این گونه‏ها به عنوان گونه‏های فراموش شده معرفی گردند و با غالبیت گونه‏های جدید، بوم نظام‏های زراعی این مناطق به طور گسترده‏ای به سمت نظام‏های کشت فشرده در حال گذار می‏باشند.
    کلیدواژگان: پایش، شاخص های رایج تنوع زیستی، شاخص های عدم دست خوردگی، کشاورزی فشرده
  • فرزانه فرامرزی، محمد صادق تقی زاده*، علی بهپوری، سحر افضلی هرسینی صفحات 171-184
    این مطالعه به منظور بررسی اثر کشت مخلوط غلات و سطوح کاربرد کود نیتروژن بر محتوای نیتروژن و عناصر کم مصرف علف های هرز و عملکرد گیاه زراعی انجام شد. تیمارهای مورد مطالعه شامل سیستم های مختلف کشت مخلوط ردیفی غلات (پنج نسبت کشت مخلوط گندم (Triticum aestivum L.): تریتیکاله (X Triticosecale wittmack) و چهار نسبت کشت مخلوط جو (Hordeum vulgare L.): تریتیکاله) و دو سطح کود نیتروژن (100 و 200 کیلوگرم در هکتار) بودند. آزمایش به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی و منابع طبیعی داراب در سال 92-93انجام شد. در این آزمایش صفات محتوای نیتروژن و عناصر کم مصرف اندام هوایی علف های هرز و عملکرد دانه گیاه زراعی بررسی شد. کمترین محتوای نیتروژن اندام هوایی علف های هرز مربوط به تیمار تک کشتی تریتیکاله با 200 کیلوگرم در هکتار نیتروژن بود. کمترین محتوای آهن و منگنز اندام هوایی علف های هرز نیز در تیمارهای 25 درصد گندم: 75 درصد تریتیکاله و 50 درصد جو: 50 درصد تریتیکاله با 200 کیلوگرم در هکتار نیتروژن بدست آمد. علف های هرزی که در تک کشتی جو رشد کردند دارای کمترین محتوای روی در بافت اندام های هوایی خود بودند و افزایش مقدار کود نیتروژن منجر به افزایش محتوای روی در آن ها گردید. کمترین محتوای مس در اندام هوایی علف های هرز در سیستم 50 درصد جو: 50 درصد تریتیکاله با سطح کود 100 کیلوگرم نیتروژن بدست آمد. بیشترین عملکرد دانه نیز مربوط به تیمار 50 درصد جو: 50 درصد تریتیکاله با 200 کیلوگرم نیتروژن بود. نتایج این مطالعه می تواند برای مدیریت اکولوژیک علف های هرز از طریق مدیریت عناصر غذایی کم مصرف و همچنین بهبود عملکرد پایدار گیاه زراعی مورد استفاده قرار گیرد.
    کلیدواژگان: آهن، تریتیکاله، روی، گندم، مس، منگنز
  • امراله اسماعیلی، محمودرضا تدین* صفحات 185-198
    با توجه به قرار گرفتن ایران در اقلیم خشک و نیمه‏خشک جهان، توجه به اثرات تنش رطوبتی بر رشد گیاه چغندرقند ضروری به نظر می رسد. اسید هیومیک می تواند به طور مستقیم، اثرات مثبتی بر رشد گیاه بگذارد. رشد قسمت هوایی و ریشه گیاه چغندرقند (Beta vulgaris L.) توسط اسید هیومیک تحریک می شود، ولی اثر آن روی ریشه، برجسته تر است، حجم ریشه را افزایش داده و باعث اثربخشی سیستم ریشه می گردد. آزمایش به صورت کرت های خرد شده در قالب طرح بلوک های کامل تصادفی در چهار تکرار در مزرعه پژوهشی دانشگاه شهرکرد با عرض جغرافیایی 32 درجه و 21 دقیقه شمالی و طول جغرافیایی 50 درجه و 49 دقیقه شرقی و ارتفاع 2050 متر از سطح دریا در سال 1394 انجام شد. تیمارها شامل چهار سطح مختلف تنش خشکی شامل حفظ رطوبت خاک در حد 100 % ظرفیت زراعی (بدون تنش)، حفظ رطوبت خاک در حد 85 % ظرفیت زراعی (تنش ملایم)، حفظ رطوبت خاک در حد 70 % ظرفیت زراعی (تنش متوسط) و حفظ رطوبت خاک در حد 45 % ظرفیت زراعی (تنش شدید) به عنوان عامل اصلی و کاربرد چهار سطح مختلف اسید هیومیک به صورت پودر HUMAX95%-WSG (شرکت بازرگان کالا) به نسبت های صفر، 2، 4 و 6 کیلوگرم در هکتار)) به صورت محلول پاشی در سه مرحله شامل مرحله چهار برگی، هشت برگی (پس از وجین) و شانزده برگی (پس از دومین مرحله خاک دهی) به عنوان عامل فرعی، اجرا شد. وزن شاخساره از ابتدای اندازه گیری ها روند افزایشی داشت ولی محدودیت آب باعث کاهش شیب افزایش وزن شاخساره شد و این کاهش شیب باعث شد تا در نهایت در تیمارهای تنش خشکی، حداکثر وزن شاخساره نسبت به تیمار شاهد، کاهش یافت. در همه سطوح آبیاری و غلظت های اسید هیومیک، شاخص سطح برگ تا اواسط فصل رشد روند افزایشی داشت و پس از آن نسبت به نیمه اول فصل رشد با شیبی ملایم تر، شروع به کاهش کرد. کاربرد اسید هیومیک باعث افزایش عملکرد ریشه شد و با افزایش مقدار اسید هیومیک، عملکرد ریشه نیز روند افزایشی نشان داد به نحوی که در هر سطح تیمار آبیاری، بیشترین عملکرد ریشه از تیمار 6 کیلوگرم در هکتار اسید هیومیک و کمترین عملکرد ریشه از تیمار عدم کاربرد اسید هیومیک به دست آمد. کاهش آب مصرفی در تیمارهای 85، 70 و 45 درصد ظرفیت زراعی به ترتیب باعث کاهش 5/0، 5/0 و 3/1 درصدی محتوای قند نسبت به تیمار شاهد شد. همچنین کاربرد 2 و 6 کیلوگرم در هکتار اسید هیومیک به ترتیب باعث 1/0 و 5/1 درصد کاهش محتوای قند شد، در حالی که کاربرد 4 کیلوگرم اسید هیومیک تاثیری بر محتوای قند نداشت. کاربرد اسید هیومیک باعث افزایش عملکرد ریشه شد به نحوی که در تیمارهای کاربرد 2، 4 و 6 کیلوگرم در هکتار اسید هیومیک، نسبت به تیمار عدم استفاده اسید هیومیک، عملکرد ریشه به ترتیب 6/41، 8/84 و 5/110 درصد افزایش نشان داد. کاربرد 6 کیلوگرم در هکتار اسید هیومیک در زراعت چغندرقند قابل توصیه می باشد.
    کلیدواژگان: درصد قند خالص، شاخص سطح برگ، عملکرد ریشه
  • گودرز احمدوند*، سمیه حاجی نیا صفحات 199-215
    به منظور بررسی تاثیر تلقیح با قارچ Piriformospora indica بر جذب و کارآیی مصرف نور سویا (Glycine max (L.) Merr.) تحت شرایط تنش کم آبی، آزمایشی به صورت کرت های خرد شده در قالب طرح پایه بلوک های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه بوعلی سینا در دو سال 1393 و 1394 اجرا شد. عامل اصلی آبیاری در سه سطح (آبیاری پس از 60، 90 و 120 میلی متر تبخیر آب از تشت تبخیر) و عامل فرعی کاربرد قارچ P. indica در دو سطح (تلقیح و عدم تلقیح با قارچ) بود. صفات مورد بررسی شامل شاخص سطح برگ، ماده خشک، جذب تشعشع، کارآیی مصرف نور و عملکرد دانه بود. در هر دو سال زراعی با اعمال تنش کم آبی، سطح برگ و تجمع ماده خشک، کاهش یافت. کاربرد قارچ در سطوح مختلف آبیاری، سبب افزایش سطح برگ و تجمع ماده خشک شد. بیشترین مقدار کارآیی مصرف نور (75/1 و 85/1 گرم بر مگاژول به ترتیب در سال اول و دوم) در گیاهان تلقیح شده با قارچ تحت شرایط عدم تنش کم آبی و کمترین مقدار آن (10/1 و 15/1 گرم بر مگاژول به ترتیب در سال اول و دوم) در گیاهان تلقیح نشده تحت شرایط تنش شدید کم آبی به دست آمد. تنش شدید کم آبی، عملکرد دانه سویا را به میزان 20/57 درصد کاهش داد. قارچ P. indica، در شرایط عدم تنش، تنش متوسط و تنش شدید کم آبی، عملکرد دانه سویا را به ترتیب 67/13، 85/22 و 14/22 درصد در مقایسه با عدم تلقیح، افزایش داد. نتایج نشان دهنده تاثیر مثبت قارچ P. indica در سطوح مختلف آبیاری بر شاخص سطح برگ، ماده خشک، جذب و کارآیی مصرف نور سویا بود، به طوری که کاربرد قارچ منجر به کاهش اثرات تنش و بهبود عملکرد سویا تحت شرایط تنش کم آبی گردید.
    کلیدواژگان: آبیاری، تشعشع فعال فتوسنتزی، قارچ درونزی، کارآیی مصرف تابش
  • کامی کابوسی*، عثمان مجیدی صفحات 217-229
    با توجه به وابستگی شدید تاریخ مناسب گندم دیم  (Triticum aestivum L.)به وقوع بارش های پاییزه و نوسان آن در سال های مختلف، پژوهش حاضر با هدف برآورد تاریخ مناسب کشت گندم دیم در استان گلستان با استفاده از داده های بارش روزانه 57 ایستگاه هواشناسی در دوره آماری مشترک 1395-1370 در پنج سطح احتمال وقوع 25، 50، 75، 85 و 95 درصد انجام شد. تاریخ کشت بر اساس وقوع اولین بارش برابر و بیشتر از 25 میلی متر طی یک دوره 10 روزه متوالی در ماه آذر انتخاب گردید. به منظور بررسی صحت نتایج و اعتبارسنجی نتایج، از یافته های پژوهش های مختلف که در مقیاس مزرعه در استان گلستان انجام شده بود، استفاده شد. نتایج نشان داد که تاریخ مناسب کشت گندم دیم در نیمه جنوبی استان زودتر از نیمه شمالی می باشد. سطح احتمال بر تاریخ کشت تاثیر معنی دار داشت، ولی اثر ایستگاه بر آن معنی دار نبود. اختلاف آماری بین تمام سطوح احتمال وقوع معنی دار بود به طوری که سطح احتمال 25 و 95 درصد به ترتیب نشان دهنده زودترین و دیرترین تاریخ مناسب کشت گندم در استان گلستان بود. در ایستگاه های مختلف استان، تاریخ کشت مناسب گندم دیم با احتمال وقوع 25 درصد بین اول تا 10 آذر، با احتمال وقوع 50 درصد بین اول تا 22 آذر، با احتمال وقوع 75 درصد بین 3 آذر تا 13 دی، با احتمال وقوع 85 درصد بین 11 آذر تا 25 دی و با احتمال وقوع 95 درصد بین 21 آذر تا 30 دی قرار داشت. با افزایش سطح احتمال پنجره تاریخ کشت در سطح استان طولانی تر گردید به گونه ای که اختلاف تاریخ کشت مناطق مختلف استان در سطح احتمال 25 درصد 10 روز و در سطح احتمال 95 درصد 40 روز ه دست آمد. بر اساس نتایج، کاهش اندک ریسک زراعت (افزایش احتمال وقوع بارش مناسب از 25 به 50 درصد) با تاخیر تاریخ کشت گندم به مدت چند روز امکان پذیر است در حالی است که کاهش بیشتر ریسک زراعت (افزایش احتمال وقوع بارش مناسب به 75، 85 و 95 درصد) از طریق تاخیر تاریخ کشت به میزان چند دهه مقدور خواهد بود. صحت سنجی و اعتبارسنجی نتایج پژوهش حاضر با نتایج پژوهش های مزرعه ای و میدانی، ضمن تائید دقت قابل قبول پیش بینی تاریخ مناسب کشت بر اساس معیار معرفی شده، نشان داد که کشاورزان استان با درک صحیح از نقش بارش پاییزه در استقرار بوته و عملکرد محصول، تاریخ کشت گندم را با سطح احتمال بالایی درست انتخاب می نمایند.
    کلیدواژگان: پنجره کشت، تاخیر در کشت، ریسک
  • رامین نظریان، علیرضا کوچکی*، مهدی نصیری محلاتی، پرویز رضوانی مقدم صفحات 231-243
    جهت بهینه سازی نسبت و آرایش کاشت در مخلوط جو و شبدر آزمایشی بصورت اسپلیت پلات در قالب بلوک های کامل تصادفی با سه تکرار درسال زراعی 93-1392 در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد اجرا شد. آرایش کاشت در پنج سطح (مخلوط ردیفی 1:1(M1)، مخلوط ردیفی 2:2 (M2)، مخلوط نواری 3:3 (M3)، مخلوط نواری 4:4 (M4) و مخلوط درهم (M5)) بعنوان کرت اصلی و نسبت کاشت نیز در پنج سطح (مخلوط افزایشی 50% شبدر + 100% جو (R5)، مخلوط افزایشی 25% شبدر + 100% جو (R4)، مخلوط جایگزینی 50% جو + 50% شبدر(R3) همرا با جو خالص (R2) و شبدر خالص (R1)) در کرت های فرعی قرار گرفتند. نتایج آزمایش حاکی از تاثیر معنی دار (P<0.01) آرایش و نسبت کاشت بر وزن خشک علوفه وهمچنین عملکرد پروتئین بود. بیشترین وزن خشک علوفه از کشت جو خالص (14731 کیلوگرم در هکتار) و مخلوط درهم (12857.9 کیلوگرم در هکتار) بدست آمد. بیشترین عملکرد پروتئین نیز از نسبت کاشت جو خالص (1962.2 کیلوگرم در هکتار) و آرایش کاشت مخلوط درهم (1584.38 کیلوگرم در هکتار) حاصل شد. اثر آرایش کاشت بر نسبت برابری زمین معنی دار نبود ولی نسبت کاشت بر نسبت برابری زمین تاثیرمعنی دار داشت (P<0.01). بیشترین نسبت برابری زمین متعلق به نسبت کاشت R5 (1.28) و آرایش کاشت M4 (1.23) بود. تاثیر آرایش و نسبت کاشت بر ضریب ازدحام نسبی (K) معنی دار نبود ولی بیشترین مقدار ضریب ازدحام نسبی متعلق به نسبت کاشت R4 (35.33) وکمترین مقدار متعلق به R5 (23.24-) بود. اثر آرایش و نسبت کاشت بر شاخص تهاجم معنی دار بود، منفی شدن شاخص تهاجم شبدربیانگر مغلوب بودن شبدر در کشت مخلوط بوده و همانگونه که آشکار شد جو دارای قابلیت رقابتی بیشتر برای تسخیر منابع در کشت مخلوط بود. شاخص های اقتصادی کاهش عملکرد واقعی (AYL) وسودمندی اقتصادی (IA) بیانگر مزیت کشت مخلوط جو و شبدرنسبت به حالت تک کشتی بوده بطوریکه بیشترین سودمندی اقتصادی در نسبت کاشت مخلوط R4 (7262833 ریال) و آرایش کاشت مخلوط M4 (4974840 ریال) حاصل گردید.
    کلیدواژگان: آرایش کاشت، کشت مخلوط، نسبت برابری زمین، نسبت کاشت
  • جواد حمزه ئی*، رحمن داودیان صفحات 245-259
    یکی از راهکارهای افزایش ثبات، ایجاد تنوع از طریق به کارگیری نظام های چندکشتی است. در این رابطه، کشت مخلوط به عنوان ابزاری سودمند جهت ارتقاء بهره برداری از منابع زیست محیطی موجود، در مقایسه با بوم نظام های زراعی تک کشتی مطرح است. بدین منظور، پژوهشی بصورت فاکتوریل در قالب طرح پایه بلوک های کامل تصادفی با 8 تیمار و سه تکرار در دانشکده کشاورزی دانشگاه تهران در سال زراعی 93-1392 اجرا شد. تیمارها شامل کشت خالص کلزا (با تراکم های 60 و 80 بوته در متر مربع) و نخود (با تراکم های 30 و 40 بوته در متر مربع) و کشت های مخلوط 30 بوته نخود+ 60 بوته کلزا، 30 بوته نخود+ 80 بوته کلزا، 40 بوته نخود+ 60 بوته کلزا و 40 بوته نخود+ 80 بوته کلزا بودند. صفات سرعت فتوسنتز، عملکرد دانه، اجزای عملکرد، شاخص کلروفیل، درصد و عملکرد روغن و پروتئین و شاخص نسبت برابری زمین اندازه گیری و ارزیابی شد. نتایج نشان داد که شاخص کلروفیل و درصد پروتئین کلزا در کشت مخلوط بیشتر از کشت خالص بود ولی بیشترین سرعت فتوسنتز هر دو گونه گیاهی در کشت خالص مشاهده شد. بیشترین عملکرد دانه کلزا (7/370 گرم در متر مربع) از تراکم 80 بوته کلزا در کشت خالص بدست آمد ولی این تیمار با کشت خالص 60 بوته کلزا اختلاف معنی دار نداشت. همچنین، کشت خالص نخود نسبت به کشت مخلوط آن، عملکرد دانه بیشتری داشت. علی رغم کاهش عملکرد دانه کلزا و نخود در کشت مخلوط نسبت به کشت خالص، شاخص نسبت برابری زمین سودمندی کشت مخلوط را تایید کرد، به نحوی که در تمام تیمارهای کشت مخلوط نسبت برابری زمین بالاتر از یک بود و بیشترین مقدار این شاخص (46/1) در کشت مخلوط 30 بوته نخود با 60 بوته کلزا مشاهده شد. لذا چنین می توان استنباط کرد که کشت مخلوط کلزا با نخود دارای برتری نسبی در مقایسه با کشت خالص بود و کارایی استفاده از زمین را افزایش داد.
    کلیدواژگان: چند کشتی، دانه روغنی، فتوسنتز، لگوم دانه ای، نسبت برابری زمین
  • پریسا ناظری، امیر حسین شیرانی راد*، سید علیرضا ولد آبادی، مجتبی میراخوری، اسماعیل حدیدی ماسوله صفحات 261-276
    بررسی واکنش ارقام مختلف کلزا (Brassica napus L.) به عوامل محیطی یکی از اصول اساسی برنامه ریزی کشور برای حصول حداکثر عملکرد کمی و کیفی است. تغییر تاریخ کاشت و خشکی از جمله عواملی است که با تغییر طول دوره رویشی و زایشی بر عملکرد محصولات زراعی تاثیر می گذارد. به منظور بررسی واکنش چهار رقم جدید کلزا به اثر تاریخ کاشت های مختلف و تنش خشکی بر خصوصیات فیزیولوژیک، مورفولوژیک و عملکرد، آزمایشی به صورت طرح فاکتوریل اسپیلیت در قالب طرح بلوک های کامل تصادفی با سه تکرار در منطقه کرج و در سال زراعی 91-1390 انجام شد. تاریخ کاشت در دو سطح تاریخ کاشت معمول و تاریخ کاشت تاخیری، آبیاری در دو سطح آبیاری معمول و قطع آبیاری از مرحله خورجین دهی به بعد در کرت اصلی و چهار رقم Agamax، Trapper، Smilla و Makro در کرت های فرعی قرار گرفتند. نتایج نشان داد کلیه خصوصیات مورد بررسی به جز شاخص برداشت، تحت تاثیر معنی دار تاریخ کاشت، تنش خشکی و رقم قرار گرفتند (P≤0.05). اثر متقابل تاریخ کاشت در آبیاری در صفات کربوهیدرات های محلول، ارتفاع بوته، تعداد خورجین در بوته و درصد روغن معنی دار گردید. همچنین اثر سه گانه نیز تنها در غلظت کربوهیدرات های محلول برگ معنی دار شد. کاشت تاخیری و قطع آبیاری سبب افزایش کربوهیدرات های محلول و کاهش غلظت کلروفیل برگ شد. همچنین اجزاء عملکرد کلزا نیز در اثر تاخیر در کاشت و قطع آبیاری کاهش یافت که در نهایت موجب کاهش عملکرد دانه و روغن کلزا شد. در بین ارقام مورد بررسی، دو رقم Trapper و Agamax با اختلاف ناچیزی نسبت به یکدیگر دارای عملکرد بهتری نسبت به دو Smilla و Makro بودند. تنش آبیاری آخر فصل همزمان با تاخیر در کاشت باعث کاهش اجزاء عملکرد و افزایش غلظت کربوهیدرات های محلول شد. عدم معنی دار بودن اثر متقابل ارقام در تاریخ کاشت برای عملکرد دانه و روغن مبین آن است که کاهش عملکرد ارقام، ناشی از تاخیر در تاریخ های کاشت از روند مشابهی برخوردار بوده است.
    کلیدواژگان: عملکرد و اجزای عملکرد، کشت تاخیری، کلروفیل، کمآبی
  • احمد گرجی زاد، افشین سلطانی، سلمان دستان*، حسین عجم نوروزی صفحات 277-294
    کمی سازی خلاء عملکرد برنج (Oryza sativa L.) برای دانستن امکان رسیدن به عملکرد بالاتر و برنامه ریزی های مناسب ضرورت دارد. بنابراین، این پژوهش با هدف مستندسازی فرآیند تولید و برآورد خلاء عملکرد برنج مرتبط با مدیریت زراعی ارقام اصلاح شده برنج در منطقه نکا واقع در استان مازندران انجام شد. به این منظور در این پژوهش کلیه عملیات مدیریتی انجام شده از مرحله تهیه بستر بذر تا برداشت در 100 مزرعه از طریق مطالعات میدانی طی سال های 1394 و 1395 ثبت شد. نتایج نشان داد که از حدود 150 متغیر مورد بررسی، مدل نهایی با هشت متغیر مستقل انتخاب شد. در مدل عملکرد، متوسط و حداکثر عملکرد به ترتیب 7194 و 9241 کیلوگرم در هکتار تخمین زده شد. متوسط و حداکثر عملکرد مشاهده شده در مزرعه نیز برابر 7178 و 8200 کیلوگرم در هکتار بود. کل خلاء عملکرد تخمین زده شده برابر 2047 کیلوگرم در هکتار بود. میزان افزایش عملکرد مربوط به متغیرهای تناوب زراعی و بذر گواهی شده به ترتیب برابر 111 و 141 کیلوگرم در هکتار بود. مقدار افزایش عملکرد مربوط به اثر کود سرک و پتاسیم مصرفی نیز به ترتیب برابر 327 و 674 کیلوگرم در هکتار معادل 16 و 33 درصد از کل خلاء عملکرد بود. همچنین، میزان افزایش عملکرد مربوط به متغیر مصرف نیتروژن بعد از گلدهی و محلول پاشی ریزمغذی ها به ترتیب برابر 324 و 214 کیلوگرم در هکتار معادل 16 و 10 درصد از کل خلاء عملکرد بود. میزان خسارت عملکرد ناشی از دو متغیر پیش کاشت کلزا و تاریخ بذرپاشی در خزانه به ترتیب برابر دو و 11 درصد از کل افزایش عملکرد (34 و 223 کیلوگرم در هکتار) بود. بنابراین، بر اساس برازش رابطه بین عملکرد مشاهده شده و عملکرد پیش بینی شده می توان بیان کرد که دقت مدل (معادله تولید) مناسب بوده و می تواند برای برآورد میزان خلاء عملکرد و تعیین سهم هر یک از متغیرهای محدود کننده عملکرد به کار گرفته شود. لذا، مدیریت زراعی هشت متغیر وارد شده در معادله تولید در مزارع کشاورزان می تواند منجر به افزایش عملکرد و کاهش خلاء عملکرد شود.
    کلیدواژگان: تحلیل مقایسه کارکرد، تناوب زراعی، کود سرک، عملکرد دست یافتنی، محلول پاشی
  • عصمت محمدی، حمیدرضا اصغری*، احمد غلامی، سرور خرم دل صفحات 295-307
    به منظور بررسی اثر سیستم‏های مختلف خاک‏ورزی و مدیریت تغذیه‏ای بر گیاه ذرت سینگل کراس 704 (Zea mays L.)، آزمایشی به صورت کرت‏های خرد شده در قالب طرح پایه بلوک‏های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه صنعتی شاهرود در سال 95-1394 اجرا گردید. تیمارهای آزمایشی شامل سیستم‏های خاک‏ورزی در دو سطح (مرسوم و کم‏خاک‏ورزی) به عنوان عامل اصلی و مدیریت تغذیه‏ای در هفت سطح شامل (شاهد، کود شیمیایی، کود دامی، بیوچار، کود شیمیایی + دامی، کود شیمیایی + بیوچار و کود دامی + بیوچار) به عنوان عامل فرعی بودند. نتایج نشان داد که مدیریت تغذیه‏ای اثر معنی‏داری بر عناصر غذایی، پروتئین دانه، ویژگی‏های بلال، وزن صد دانه، عملکرد بیولوژیک، عملکرد دانه و شاخص برداشت داشت.کمترین و بیشترین نیتروژن دانه، وزن بلال، عملکرد بیولوژیک و عملکرد دانه به ترتیب مربوط به شاهد و کود شیمیایی بود. کود شیمیایی + دامی نیتروژن دانه، وزن بلال، عملکرد بیولوژیک و عملکرد دانه را به ترتیب 89/13، 19/56،04/47 و 41/60 درصد نسبت به شاهد افزایش داد. همچنین کود شیمیایی + بیوچاربه ترتیب باعث افزایش 81/14، 78/52، 69/42 و 32/56 درصدی نیتروژن دانه، وزن بلال، عملکرد بیولوژیک و عملکرد دانه نسبت به شاهد شد. کود شیمیایی + دامی و کود شیمیایی + بیوچار با کود شیمیایی تفاوت معنی‏داری را نشان ندادند. همچنین بین دو سطح خاک‏ورزی مرسوم و کم‏خاک‏ورزی اختلاف معنی‏داری در عناصر غذایی، پروتئین دانه، ویژگی‏های بلال، وزن صد دانه، عملکرد بیولوژیک، عملکرد دانه و شاخص برداشت مشاهده نشد. بنابراین می‏توان به منظور جلوگیری از اثرات مخرب خاک‏ورزی مرسوم و آلایندگی خاک‏های اراضی زراعی به کود شیمیایی نیتروژن و حفظ کیفیت و سلامت خاک، استفاده از کم‏خاک‏ورزی به همراه کود شیمیایی + دامی و کود شیمیایی + بیوچار را توصیه نمود.
    کلیدواژگان: بیوچار، پروتئین دانه، خاکورزی مرسوم، عملکرد دانه، کمخاکورزی، کود دامی
  • دیاکو رسولی*، رقیه محمدپور وشوایی، براتعلی فاخری صفحات 309-320
    به منظور بررسی تاثیر تنظیم کننده های زیستی بر صفات مورفولوژیک، فیزیولوژیک و ترکیبات اسانس گیاه داروییAmmi visnaga (L.)  آزمایشی در قالب طرح بلوک های کامل تصادفی در دانشگاه زابل در سال زراعی 94-1393 انجام گرفت. تیمارهای استفاده شده در این پژوهش شامل اسید سالیسیلیک، اسید سینامیک و اسید بنزوئیک با سه سطح 5، 10 و 20 میلی گرم بر لیتر و اسید آمینه های فنیل آلانین و تیروزین با سه سطح 50، 100 و 200 میلی گرم بر لیتر بودند. نتایج نشان داد که تنظیم کننده های زیستی باعث افزایش میزان صفات مورد بررسی شدند. همچنین تیمار اسید بنزوئیک 20 میلی گرم بر لیتر بیشترین تاثیر را به نسبت سایر تیمارها داشت؛ به طوری که باعث افزایش معنی داری در رشد رویشی (16/46 درصد)، محتوای آب نسبی (17/60 درصد)، رنگیزه های فتوسنتزی (کلروفیل a، کلروفیل b، کارتنوئید، کلروفیل  a+ کلروفیل b و (کلروفیل  a+ کلروفیل b)/ کارتنوئید به ترتیب 63/77، 6/60، 67/66، 32/73 و 12/19 درصد)، هیدرات های کربن (43/53 درصد)، عملکرد میوه (1/60 درصد) و درصد و عملکرد اسانس (78/72 و 28/32 درصد) به نسبت شاهد شد. نتایج حاصل از این تحقیق بیان داشت که کاربرد تنظیم کننده های زیستی با هدف کاهش مصرف کودهای شیمیایی، در افزایش عملکرد کمی و کیفی گیاه دارویی Ammi visnaga و همچنین پایداری تولید و حفظ محیط زیست تاثیر مثبتی داشته است.
    کلیدواژگان: اسانس، اسید آمینه، تنظیم کننده های زیستی، ترکیبات فنلی، Ammi visnaga
  • نیلوفر آقایی پور، همت اله پیردشتی*، محسن زواره، حسین اسدی، محمدعلی بهمنیار صفحات 321-334
    یکی از روش های توانمند در جهت ارزیابی پتانسیل عملکرد و دلایل خلا عملکرد، آنالیز خط مرزی می باشد. پژوهش حاضر به منظور بررسی تعیین عملکرد بهینه و تاثیر احتمالی اجزای وابسته به عملکرد در شالیزارهای برنج (Oryza sativa L.) دشت فومنات استان گیلان (رقم طارم هاشمی) اجرا شد. جهت توصیف رابطه بین عملکرد و اجزای عملکرد از مدل های دو تکه ای، دندان مانند و درجه دوم استفاده گردید. برای انتخاب مدل برتر از چهار معیار میانگین قدر مطلق خطا، ضریب تبیین، ضرایب رگرسیون خطی ساده و ضریب تغییرات استفاده و پس از انتخاب مدل برتر، خلا عملکرد، عملکرد بهینه و مقادیر بهینه اجزای عملکرد با استفاده از روش آنالیز خط مرزی محاسبه شدند. در بین مدل های برازش یافته، مدل دوتکه ای برای دو ویژگی تعداد خوشه در متر مربع و وزن صد دانه دارای کمترین RMSE و ضریب تغییرات بوده و به خوبی توانسته به توصیف روند تغییرات بپردازد. علاوه براین، تابع دندان مانند با کمترین RMSE و ضریب تغییرات برای توصیف روند تغییرات ویژگی تعداد دانه پر مورد استفاده قرار گرفت. با توجه به مدل ها، خلا عملکرد در دشت فومنات برابر با 63/3 تن در هکتار با میانگین عملکرد بهینه و عملکرد کشاورز به ترتیب برابر با 44/8 و 81/4 تن در هکتار برآورد شد. همچنین، مقادیر بهینه اجزای عملکرد شامل تعداد خوشه در متر مربع، تعداد دانه پر در خوشه و وزن صد دانه (گرم) به ترتیب برابر با 560، 9/83-47 و 18/2 به دست آمد.
    کلیدواژگان: تعداد خوشه، رگرسیون غیرخطی، ضریب تبیین، مدل دندانمانند، مدل دو تکهای
  • سیده زهره حسینی، حسن فیضی*، صفیه وطن دوست جرتوده، مسعود علیپناه صفحات 335-347
    پونه (Mentha longifolia L. syn. Mentha sylvestris L.) گیاه دارویی و معطر ارزشمند متعلق به خانواده نعناعیان می باشد. به منظور بررسی صفات مورفولوژیکی  Mentha longifolia L.از 10 رویشگاه در استان فارس و استان خراسان رضوی (سپیدان، بوانات، کوار، کازرون، فسا، تربت حیدریه، مشهد، نیشابور، کاشمر و چناران) در زمان گلدهی، نمونه گیری انجام شد. اطلاعات مربوط به رویشگاه ها یادداشت برداری و از هر رویشگاه 10 نمونه گیاهی کامل انتخاب و 19 صفت کمی و کیفی برای هر اکوتیپ بررسی شد. نتایج نشان داد که تنوع قابل ملاحظه ای از نظر خصوصیات مورفولوژیکی در بین اکوتیپ ها وجود داشت. بازده متوسط تولید اسانس پونه در رویشگاه های مشهد 83/1 درصد، کاشمر 8/1 درصد، چناران 87/0 درصد، تربت حیدریه 25/1 درصد، نیشابور 27/1 درصد، سپیدان 75/1 درصد، بوانات 55/1 درصد، کوار 75/1 درصد، کازرون 17/1 درصد، فسا 37/1 درصد تعیین شد. آنالیز همبستگی، وجود همبستگی مثبت و معنی داری بین برخی صفات مهم همچون ارتفاع گیاه با تعداد ساقه فرعی  (r=0.5)و تعداد گل (r= 0.59) را نشان داد. تجزیه به عامل ها نشان داد که صفاتی همچون طول برگ، عرض برگ و نوک پهنک با قرار گرفتن در مولفه اول بیشترین سهم در توجیه تغییرات داده ها را به خود اختصاص داد. تجزیه خوشه ای، جمعیت های مورد مطالعه را در 4 گروه مجزا تقسیم بندی کرد. با توجه به میزان بالای عملکرد اسانس در رویشگاه مشهد، این منطقه می تواند به عنوان رویشگاه مستعد جهت پرورش این گونه به منظور استخراج اسانس معرفی شود.
    کلیدواژگان: تنوع، خصوصیات مورفولوژیک، تجزیه خوش های، گیاه دارویی
  • عبدالله سلطان احمدی، احمد نظامی*، محمد کافی، حمید رضا خزاعی صفحات 349-364
    فستوکا (Festuca sp.) یک گونه پرکاربرد و با اهمیت جهت مراتع، تعلیف دام و فضای سبز شهری است. اکوتیپ های متعددی از این گونه در ایران رشد می کنند و برای موفقیت در کشت و رشد مناسب آنها در مناطق تحت تنش، اطلاعات کمی در دسترس می باشد. زمستان های سرد از جمله ویژگی های مناطق معتدله در ایران است. از این رو، انتخاب اکوتیپ های متحمل به سرمای فستوکا جهت کشت در این مناطق ضروری است. به این منظور، آزمایشی با هدف ارزیابی تحمل به سرما در اکوتیپهای فتان بلند (Festuca arundinacea L.) در شرایط مزرعه و کنترل شده به صورت اسپلیت پلات در قالب طرح بلوکهای کامل تصادفی در دو شرایط مزرعه و کنترل شده در دانشکده کشاورزی دانشگاه فردوسی مشهد در سال زراعی 93-1392 انجام شد. در مزرعه عامل اصلی دو تاریخ کاشت پاییزه (15 مهرماه و 15 آبان ماه) و عامل فرعی شامل 23 اکوتیپ جمعآوری شده از نقاط مختلف ایران بود و در شرایط کنترل شده اکوتیپ های فتان کشت شده در زمان های مشابه با مزرعه در معرض چهار دمای شاهد (دمای محیط طبیعی)، 14-، 17- و 20- درجه سانتیگراد) قرار گرفتند. نتایج آزمایش مزرعه ای نشان داد که اثر متقابل تاریخ کاشت × اکوتیپ بر روز تا سبز شدن، درصد بقاء، عملکرد دانه و زیستتوده معنی ‎دار بود. درصد بقاء اغلب اکوتیپ ها در کشت دوم بیشتر از کشت اول بود، با وجود این در اکثر اکوتیپ های با تاخیر در کشت، روز تا سبز شدن، عملکرد دانه و زیست توده کاهش داشت. در شرایط کنترل شده، اثر تاریخ کاشت × اکوتیپ بر درصد بقاء، سطح سبز و وزن خشک بوته معنی ‎دار بود. با تاخیر در کشت، درصد بقاء در اغلب اکوتیپ ها به طور معنی ‎داری افزایش یافت. تاخیر در کاشت، سبب کاهش وزن خشک در 52 درصد اکوتیپ ها شد. در هر دو شرایط مزرعه و کنترل شده اکوتیپ های اصفهان- ایستگاه قزوه 1375، بروجن، داران، داران- دامنه، گندمان- سناجان، مشهد، ساری، گلستان و قوچان- سیدآباد از نظر درصد بقاء، وزن خشک و عملکرد نسبت به سایر اکوتیپ ها دارای برتری معنی ‎داری بودند و متحمل ترین اکوتیپ ها معرفی شدند.
    کلیدواژگان: ارتفاع، تاریخ کاشت، درصد بقاء، سطح سبز، عملکرد دانه
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  • M.R. Gazikinejad, Abdollah Mollafilabi * Pages 1-15
    Introduction
    Biodiversity of medicinal and aromatic plants contributes significantly towards human livelihood and development and thus plays a predominant role in the wellbeing of the global population. According to WHO reports, around 80 % of the global population still relies on traditional medicines and natural substances. Descurainia sophia L. seed, also known as flixweed, a commonly used herbal medicine in Iranian folk medicine is one of those medicinal herbs with prevalent use. Agronomic practices are required to be standardized for realizing yield potential. Among the different agronomic practices, foliar spray of macronutrients is most important factor in determining the yield. Plant density is another important agronomic factor that manipulates micro- environment and affects growth, development and yield of plants. Within certain limits, increase of plant population density declines the growth and yield per plant but the reverse occurs for yield per unit area. The optimum plant density to attain highest yield may vary with the genotype and agronomic factor. Hence the purpose of this study was to determine the effects of plant density and leaf spraying on growth, yield and yield components of flixweed under Torbat-e Jam climatic conditions.
    Materials and methods
    In order to study the effects of plant density and leaf spraying of growth, biological yield, seed yield, yield components and harvest index of flixweed, an experiment was conducted as factorial layout based on a randomized complete block design with three replications at the Agricultural Research Station, Azad University of Torbt-e Jam, Khorasan-e Razavi during growing season of 2016-2017. Treatments included four plant densities (10, 20 and 40 plants.m-2) and leaf straying at three plant stages (such as emergence, before flowering and early seed formation stages) and control (without spraying). Leaf spraying was done using complete fertilizer (5:1000). Studied traits were plant height, number of branches per plant, 1000- seed weight, seed yield, biological yield, dry weight of shoot, fresh weight of shoot and harvest index. The treatments were run as an analysis of variance (ANOVA) to determine if significant differences existed among treatments means. Multiple comparison tests were conducted for significant effects using the Duncan’s test.
    Results and discussion
    The results showed that the simple effect of plant density was significant (p≤0.05) on number of branches per plant and harvest index of flixweed. The simple effect of foliar spraying was significant (p≤0.05) on number of branches per plant and 1000-seed weight of flixweed. The interaction effect between plant density and foliar spraying had significant effect on number of branches per plant, dry weight of shoot, seed yield, biological yield and harvest index of flixweed. The highest seed yield, biological yield and dry weight of shoot were recorded in 40 plants.m-2+ foliar spraying at early seed formation with 99, 495 and 396 g.m-2, respectively. The minimum seed yield was observed in 10 plants.m-2+ without spraying with 35 g.m-2. The lowest biological yield and dry weight were obtained in 20 plants.m-2+ foliar spraying at early seed formation with 168 and 126 g.m-2, respectively. The results for correlation coefficients between yield and yield components revealed that the highest coefficient was calculated for biological yield and dry weight of shoot (r=0.97**).
    Conclusion
    Agronomic management strategies had significantly effect on growth, yield, and yield components of flixweed. Generally, plant density and nutrient management are two effective techniques for agronomic management of medicinal plants such as flixweed that may decline the necessity for chemical and intensive approaches to the plant. The findings of the present study indicate that foliar spraying would be an advisable treatment that produces higher seed yield. In total, according to the results, the plant density of 40 plants.m-2+ foliar spraying at early seed formation is recommended to realize maximum seed yield flixweed cultivation in Torbat-e Jam region, Iran.
    Keywords: Complete fertilizer, Early seed formation, Dry weight of shoot, Seed yield
  • Reza Sadr Abadi, Habib Sheikh, Abdollah Filabi * Pages 17-31
    Introduction
    Saffron (Crocus sativa L.) is the most expensive spice. Better farming and improvement agronomic operations are process of production for qualitative and quantitative improvement of the product as a result of research, education and promotion of new methods of planting, growing and harvesting product. Application of new techniques to saffron could help to compete in global markets with saffron produced in other countries. The researches that have been conducted about the influence of nutrients on saffron quality and quantity, have shown that flower yield and stigma yield stigma were affected by nutrient positively. In this paper we aimed to study the effects of two types of bio-fertilizers (Humus-s and Aa40) and different concentrations on the flower yield, daughter corm yield, stigma yield, leaf weight and leaf length of saffron under the climatic conditions of Kardeh, Iran.
    Materials and methods
    In order to study the effects of two types of bio-fertilizers and their concentrations on flower yield, stigma yield and daughter corm yield of saffron, a field experiment was performed in a 4-year field at Kardeh dam during 2016-2017. This experiment was carried out as two-factorial based on a randomized complete block design with three replications. The first factor comprised of two types of bio-fertilizers (such as Humus-s and Aa40) and the second factor included concentrations of 0, 1, 1.5, 2 and 2.5 per 1000 as leaf spraying in two times. Fresh weight of flower, dry weight of stigma, fresh weight of stigma, dry weight of flower without stigma, fresh weight of flower without stigma, fresh weight of leaf, dry weight of leaf, weight of daughter corms, number of daughter corms, fresh weight of stigma, fresh weight of flower without stigma, flower number, number of daughter corm in different weight groups such as 0.1-5, 5.1-10, 10.1-15, and >15 g and leaf length of saffron were studied traits. The treatments were run as an analysis of variance (ANOVA) to determine if significant differences existed among treatments means. Multiple comparison tests were conducted for significant effects using the Duncan’s test.
    Results and discussion
    The results indicated that the fertilizers had not significantly effect on none of studied traits. The effect of different concentrations was significant on fresh weight of flower, dry weight of stigma, dry weight of flower without stigma, fresh weight of leaf, weight of daughter corms, fresh weight of stigma, fresh weight of flower without stigma, number of flower, number of daughter corms with >15 g weight and leaf length of saffron. The interaction effect between fertilizer type and concentrations had significantly effect on fresh weight of leaf. The highest dry weight of stigma and dry weight of daughter corms were observed in 2.5 per 1000 with 1239.98 and 4955 g.m-2, respectively. The lowest for the traits were related to control with 930.56 and 4085 g.m-2, respectively. The maximum and the minimum number of daughter corms were obtained in 2 per 1000 and control with 415 and 380.33 No.m-2, respectively.
    Conclusion
    It seems that foliar spraying had positive effects on growth and yield of flower, stigma and daughter corm of saffron.  So, it is recommended that foliar spraying is used in the production of saffron and besides reducing use of other common fertilizers, other benefits of this fertilizers are enjoyed. Foliar spraying in order to accurate control of releasing nutrients can be an effective step towards achieving sustainable agriculture and compatible with the environment. Using foliar spraying as a substitute for conventional iron chelate fertilizers, element of iron fertilizer is released gradually and in a controlled way and as a result provides nutrient to plant more effectively.
    Keywords: Energy productivity, Energy use efficiency, Field operations, Fossil fuel
  • Shojaat Zare, Ali Akbar Moayyedi * Pages 33-51
    Introduction
        Tillage and preparation of soil, alone account for a significant part of the crop production costs, which according to statistic of Ministry of Jihad-e-Agriculture in 2015, about 9% of the total cost per hectare of wheat (28 million Riyal) has been allocated to plowing and discs. Therefore, in order to reduce costs, energy consumption, equipment depreciation, saving during operation, maintaining the environment and sustainability of the production system, the approach to low tillage and no tillage has grown further. However, the development of these methods is accompanied by barriers that can be largely categorized into three broad categories: access to machinery, social barriers and economic issues. Farmers are worried that reducing the income resulting from the elimination of some inputs, especially tillage is more than reducing its costs. Here are two points that affect farmers' decision-making: One is which crop rotation is sustainable for sustainable farming? And the other is which sustainable crop rotation, can serve the economic interests of farmers? The past studies have shown that in agronomic rotations, because of the variety of products, it is necessary to evaluate the treatments in order to select the best alternatives. In addition, in conservation methods, reducing production costs cannot be a reason for the superiority of treatments with minimum tillage and it is necessary to evaluate these treatments economically.
    Material and methods
                  This research was carried out with the aim of evaluating the economic efficiency of conservation agricultural system and comparing it with conventional agricultural practice in two crop rotations include  conventional and sustainable systems. Experiments were conducted using a split-plot design based on randomized complete block with three replications in research station of Torogh Mashhad during 2011-16 growing seasons. Main factor was three tillage methods include 1-Conventional Tillage: Plow + Disc + Leveling + Faro + Seed planter, (CT), 2-Reduced Tillage : Disc +Faro + Seed planter, (RT) and 3-No Tillage: direct plant by Seed planter (NT)) were allocated in main plots and three residue management (Zero (R0), 30% (R1) and 60% (R2) of residue retention) were assigned in sub plots. Experimental treatments were compared and valuated  by using partial budgeting method. 
    Results and discussion
              Results showed that sustainable crop rotation, SCR, has a higher overall production value than conventional crop rotation, CCR,. The ratio of the production value of SCR to CCR is between 1.64 to 2.1 and 1.8 on average, and the ratio of costs is almost 1.08, but the net profit ratio of SCR to CCR is from 1.9 to 2.6 and 2.1on average. However, the difference between cost of two crop rotation is almost 8%, but the difference in their water consumption is 3% (71400 cubic meters in the CCR versus 73695 cubic meters in the SCR), in other words, in the SCR The value of production per cubic meter is 56159 Rials, in the event that in the CCR is 27157 Rials. Increasing tillage, increase the benefit of treatments. Nevertheless, increasing in residue retention in NT, decrease benefit. Although, in RT and CT increasing in residue retention to R1 increase and to R2 decrease benefit. Therefore, in RT and CT, economical treatment is R1. In the CCR, the highest net income and rate of return treatment was CT + R1. In the event that in SCR, the highest income and the lowest cost  treatment was NT + R0. In the CCR, the treatment of CT + R1, with the net benefit of 246371580 Rials and a rate of return, ROR, 437%, had the highest net benefit and ROR. In the event that in the SCR, the treatment of NT + R0, with the net benefit of 450020790 Rials had the highest income and the lowest cost. These results indicate that applying conservation agriculture in the CCR isn’t economical. But if the crop rotation changes, then the conservation agriculture in the field of no tillage is economical, and isn’t for residue retention. ConclusionResults showed that SCR has a higher overall production value than CCR. In the CCR, the highest net income and rate of return treatment was CT + R1. In the event that in SCR, the highest income and the lowest cost  treatment was NT + R0.
    Keywords: Net benefit, Partial budgeting, Rapeseed, Rate of return, Wheat
  • Mohammad Taghi Feyzbakhsh *, Mohammad Ali Dorri, Nasibe Rezvantalab Pages 53-68
    Introduction
    Nowadays, the agricultural sector is largely dependent on energy consumption due to response to increasing food requirements for the growing population of the earth and providing adequate and appropriate foods. Recently evaluation of input, output and global warming potential (GWP) have been applied in sciences of agriculture. Although, further crops production without considering the environmental issues and lack of evaluation the energy indices, do not seem logical. On the other hand, high price and limitation of energy resources used in the agricultural products is also other important reasons for energy analysis in agricultural ecosystems. Energy shortage and importance of agriculture in feeding the world oriented many studies to evaluating the quantities of fuel and energy in different products and different sites. Different quantities of energy are consumed per each hectare of potato production based on different inputs such as fertilizers, fossil fuels, electricity, seeds, pesticides and machinery that will lead to greenhouse gases emission including CO2, N2O and CH4. Increasing the concentration of such gases in the atmosphere can cause global warming. So serious attention to reducing energy consumption and greenhouse gas emissions seems to be necessary. For this purpose, fuel and energy consumption and greenhouse gas emissions were investigated in all potato fields in Golestan province. Finally, some strategies were presented for their consumption reduction.
    Materials and Methods
    In order to determine the fuel and energy consumption and greenhouse gas emissions and how to reduce it, 95 potato fields in Golestan province were investigated through systematic random sampling. The amount of inputs, including fossil fuels was recorded and energy analysis was done based on the consumed inputs. Also, the greenhouse gases emission of carbon dioxide, nitrous oxide and methane derived from energy consumption for agricultural inputs and agronomic operations was calculated. Finally, energy efficiency, energy productivity, specific energy, net energy and total GWP, GWP in area unit, product weights, input energy and output energy were also calculated.
    Results and Discussion
     Results showed that total input and output energy were 30.8 and 79.2 GJ per hectare, respectively. In a study, the total input energy in potato fields in Ardabil province was 81.6 and 102.4 GJ.ha-1, respectively (Mohammadi et al., 2008). Also the most direct input energy from fuel in potato farms was 14.1 percent and the highest indirect input energy farms was 27 percent that related to fertilizers. The ratio of output to input energy, energy productivity and specific energy in potato farms were calculated 2.5, 0.71 and 1.4 respectively. Energy productivity in potato fields in Kurdistan province for commercial and traditional fields were calculated 0.38 and 0.39 respectively, which shows that energy productivity in Golestan province is higher than Kurdistan province.
    The GWP observed in potato farms was 1350.2 (kg CO2.ha-1). For potato farms the highest GWP was related to nitrogen fertilizer and fuel consumption. Results indicated that consumption of fuel and fertilizers constitute the high percent of energy consumption and greenhouse gas emissions.
    Conclusions
    Based on this study results, the use of devices that reduce fuel consumption is recommended, also need for research on crop rotation and nitrogen fixation plants in rotation were revealed. The use of Rhizobia bacteria and biological nitrogen fixation in rotation and organic fertilizers can be effective in reducing the use of nitrogen fertilizers and consequently, energy consumption and GHG emission. On the other hand, it can be said that increasing the yield along with reducing inputs consumption, especially fossil fuels and nitrogen fertilizer, can be effective in increasing energy efficiency.
    Keywords: Energy productivity, Energy use efficiency, Field operations, Fossil fuel
  • Esmaeil Rezaei, chiyaneh *, Yahia Rasouli, Jalal Jalilian, Masoud Ghodsi Pages 69-85
    Introduction
    Intercropping as a method of sustainable agriculture is defined as the simultaneous growing of two or more crops during the same season on the same area of land. Intercropping compared with monoculture has many advantages including the more efficient use of resources (water, nitrogen, and radiation), enhances yield quality, prevention of soil erosion, and reduced incidence of insects, diseases, and weeds. Javanmard et al. (2012) studied the agronomical, ecological and economic evaluation of wheat- chickpea intercropping under rainfed condition of Maragheh reported that the highest pods number per plant, seed number per plant, seed yield of chickpea and spikelet number per spike, grain number per spike, grain yield, protein content, and protein yield were obtained in the sole crops. This research aimed to study the effects of different fertilizers (biological, chemical, integrative) and intercropping of barley with chickpea on their yield and qualitative traits.
    Materials and methods
    This study was carried out with a factorial design based on Randomized Complete Block Design with three replications and 24 treatments in Naqadeh, Iran during the growing season of 2014-2015. The first factor included six intercropping patterns consist of 1-row chickpea + 1-row barley, 2-row chickpea + 2-row barley, 4-row chickpea + 2-row barley and 2-row chickpea + 4-row barley and monocropping of each crop and the second factor was included control (no fertilizer), 100% chemical fertilizers (NP), biofertilizers and biofertilizers +50% chemical fertilizers.
    Barley was harvested when spike turned brown and chickpea was harvested when the first pod of the plants fully matured. Field data were collected by cutting 10 plants randomly from each plot and yield component of each plant was considered as the average for each plot.
    Analysis of variance had been done by using SAS 9.4 software was performed for studied parameters. Means were compared with LSD at 5% probability level (P < 0.05).
    Results and discussion
    Results showed that intercropping patterns had a significant effect on all of the mentioned traits except the number of seeds per pod of chickpea pea. There was no significant interaction effect between intercropping pattern and fertilizer. The maximum and the minimum grain yield and biological yield of chickpea were obtained at monocropping and row intercropping (1-row chickpea + 1-row barley), respectively. In addition, the highest and the lowest grain yield and biological yield of barley were obtained from monocropping and 1-row chickpea + 1-row barley, respectively. Also, the effect of fertilizer was significant on all traits of both crops. The highest seed yield and biological yield of chickpea were achieved in the combined usage of fertilizers with 104.60 and 339.53 g.m-2 and the maximum grain yield and biological yield of barley were obtained in use of integrated application fertilizers with 215.90 and 1187.53 g.m-2, respectively. The highest and the lowest grain protein of barley and chickpea were obtained in the combined usage of fertilizers and control (no fertilizer), respectively.Calculation of LER revealed that the maximum LER (1.34) was obtained for intercropping (2-row of barley + 2-row of chickpea) with biochemical fertilizer, respectively. This means that intercropping improved land use efficiency by 34%, compared with monocropping.
    Conclusion
    According to the results of this experiment, the highest grain yield for both plants (chickpeas and barley) were achieved in monocropping. However, the lowest grain yield of chickpeas and barley were obtained in intercropping patterns with ratios of 1:1, respectively. The higher grain yield of mono-cropped may be due to the fewer disturbances in the habitat in a homogeneous environment under monocropping systems. In the condition of application biofertilizer, more nutrient accessibility led to an improvement in the yield of chickpeas and barley. Results indicated that application of biofertilizers enhanced the grain and yield components. Among treatments, the combined usage of fertilizers (%50 chemical fertilizers+ biofertilizer) showed a greater increase in studied traits than individual consumption. The positive effect of biofertilizer may result from its ability to improve the availability of nitrogen, phosphorus and other nutrients especially under limited irrigation of the soil which causes decreasing on the nutrient's availability.
    Keywords: Azotobacter, Land equivalent ratio, Planting pattern, Pseudomonas, Sustainable agriculture
  • Farzad Mondani *, Ali Bozorgi Hossein Abad, Mohsen Saeedi, Alireza Bagheri, Hassan Heidari Pages 87-102
    Introduction
    Nitrogen is the most important mineral nutrient for crop growth and development that improve quality and quantity of yield. It is used in modern agroecosystems to maximize yields. In harvest time, about 40 to 60% of applied nitrogen to the fields must be compensated by different fertilizers. Nevertheless, only 30 to 50% of consumed nitrogen is taken up by the crops and high amount of it is lost. Improved economic cost and environmental concerns augmented managing use of fertilizers. Improvement of nitrogen use efficiency has become an urgent target in crop production for efficient nitrogen utilization, maximum energy saving and productivity. In the sustainable agriculture approaches, there are several ways for increasing nitrogen use efficiency such as selection of suitable varieties. There is about six million hectare of wheat in Iran. Kermanshah Province with 6.4% of cultivation area and 6.6% of wheat production is the fifth place in Iran. In this province consumes large amounts of N fertilizers annually in the wheat agroecosystem. Therefore, the aims of this study were evaluating nitrogen uptake and utilization efficiency, and final nitrogen use efficiency in the wheat production system under Kermanshah weather condition.
    Materials and methods
    A split-plot experiment based on the randomized complete block design with three replications was conducted in the Campus of Agriculture and Natural Resources Field at Razi University under Kermanshah weather condition during 2015-2016. The experiment treatments were four levels of nitrogen fertilizer rate (90, 180, 300, 360 kg ha-1 of urea) as main-plot and four wheat varieties (Parsi, Zare, Pishgam and Orum) as sub-plot. The evaluated traits were included total dry weight yield, grain yield, biomass nitrogen content, nitrogen uptake efficiency (NUpE), nitrogen utilization efficiency (NUtE) and nitrogen use efficiency (NUE). Data analysis was done by SAS software (Ver 9.4) and means comparison by LSD tests were also carried out at the level of 5%.
    Results and discussion
    The results showed that under nitrogen fertilizer rate treatments, Pishgam variety in comparison with other varieties had the most satisfying ecophysiological characteristics. Regardless of studied varieties, by increasing the rate of urea fertilizer from 90 to 360 kg ha-1 total dry weight yield (65.9%) and grain yield (73.1%) were improved. In this situation, Pishgam variety had the highest grain yield (37.4%) compared to other varieties. The highest and the lowest grain yield were related to Pishgam variety (8950 kg ha-1) in 360 kgurea ha-1 treatment and Orum variety (1264 kg ha-1) in 90 kgurea ha-1 treatment, respectively. The results also showed that the highest NUpE observed in the lowest level of fertilizer rate for Zare variety (0.7 kg Nuptake/kg Nsoil+applied) and the lowest NUpE observed in the highest level of fertilizer rate for Orum variety (0.26 kg Nuptake/kg Nsoil+applied). The greatest and the lowest NUtE were for Pishgam variety (59 kg grain/kg Nuptake) in 90 kgurea ha-1 treatment and Orum variety (37 kg grain/kg Nuptake) in 360 kgurea ha-1 treatment, respectively. In relation to NUE, Pishgam variety had the highest value (36 kg grain/kg Nsoil+applied) under 90 kgurea ha-1 treatment and Orum variety had the lowest value (10 kg grain/kg Nsoil+applied) under 36090 kgurea ha-1 treatment. Our results also indicated that grain yield had a significant positive correlation with nitrogen content at anthesis and maturity while there was a significant negative correlation with NUpE and NUE. The relation of grain yield with  NUtE was positive and no significant.
    Conclusion
    The results showed that most of traits of wheat varieties such as grain yield and total dry weight yield were improved by increased nitrogen fertilizer rate. But, evaluation of traits related to nitrogen efficiency showed that NUE reduced by increasing of nitrogen fertilizer rate for all wheat varieties. The NUpE compare to NUtE had more effect on NUE. The grain yield had a significant negative correlation with NUpE and NUE but it had a positive correlation with NUtE. Although, breeding of varieties with higher NUtE can be cooperate an effective role in improvement of NUE but it seems that emphasis on nitrogen management consumption methods can be more effective.
    Keywords: Biomass nitrogen content, Nitrogen uptake efficiency, Nitrogen utilization efficiency, Nitrogen use efficiency, Wheat varieties
  • Elahe Boroumand Rezazadeh, Alireza Koocheki *, Parviz Rezvani Moghaddam, Mehdi Nassiri Mahallati, Amir Lakzian Pages 103-122
    Introduction
    Carbon sequestration is defined as the permanent gain of carbon by soil, plant or water. Soil as the largest terrestrial carbon pool plays an important role in the global carbon cycle. Due to the role of agricultural systems in CO2 emission, attention to the carbon cycle in agricultural systems is of prime importance. So, the interest in agricultural soils and plant biomass as a carbon sink and an operational mechanism for reducing the atmospheric CO2 level, is increasing. It is estimated that world’s crop-based agriculture occupies 1.7 billion hectares, which can store up to 170 Pg carbon. Thus, the aims of this study were to simulate the relationship between crop residue decomposition rate with carbon to nitrogen ration (C:N) (an index of residue quality) as well as soil moisture regimes (the most important factors in residue decomposition) and also estimation of the attainable carbon sequestration in irrigated systems of five major crops in Iran based on the simulated model.
    Materials and methods
    Residue decomposition rate of wheat, maize, rapeseed, cotton and soybean (with C:N ratios of 131, 69.7, 87.1, 57.8 and 95.9 , respectively)  in different soil moisture regimes (100, 60 and 30 percentage of field capacity) was studied in a 390-day incubation experiment. Study data was used for simulation of residue decomposition and relative decomposition rate was defined as a function of moisture (fm), C:N (fC:N) and temperature (ftemp). The simulated model was used to evaluate attainable carbon sequestration of the studied crops in five years from 2002-2003 to 2006-2007 based on yield, harvest index and shoot to root ratio in three scenarios of residue retention (100, 50 and 0 percentage of total residue produced) as well as three scenarios of soil moisture regimes of 100, 60 and 30 percentage of field capacity for different provinces of Iran. In this step, residue decomposition during one year after harvest was calculated using fm, fC:N and ft. The difference between proportions of the residue returned to the soil and decomposed residues were considered as un-decomposed residue which was multiplied by 0.45 to gain attainable carbon sequestration. Data of attainable carbon sequestration was analyzed as factorial experiment based on completely randomized design.
    Results and discussion
    Results indicated that higher C:N and therefore lower residue quality caused lower residue decomposition rate. This parameter was also decreased in soils with lower moisture. Effects of soil moisture on reside decomposition was more pronounced than residue quality. comparison of attainable carbon sequestration in Iran’s provinces revealed that in wheat cropping systems: Kermanshah and Sistan and Balouchestan, in maize: Qazvin and Southern Khorasan, in rapeseed: Isfahan and Boushehr, in cotton: Eastern Azarbaijan and Hormozgan and in soybean cropping system: Ardebil and Eastern Azarbaijan provinces had the highest and lowest attainable carbon sequestration, respectively. Attainable carbon sequestration in all crops was decreased with increasing soil moisture from 30 to 60 and 100% of FC and decreasing residue retention from 100 to 50 and 0 % of total crop residue production. Maize and soybean showed the highest and lowest capability of carbon sequestration, respectively.
    Conclusion
    Results of the present study highlight the effects of environmental factors such as soil moisture as well as inherent properties of plant residues on residue decomposition. Climate and residue quality are the main determining factors of soil microorganisms activity and residue decomposition and therefore soil attainable carbon sequestration. Better soil moisture condition and temperature, also higher residue quality increases microorganisms activity resulting in more residue decomposition. Furthermore, plant biomass and residue management affects attainable carbon sequestration. Resultant of the mentioned factors determines attainable carbon sequestration in soils of agroecosystems. Regarding to the total carbon sequestration of afore-mentioned crops, Ardebil and Sistan and Balouchestan provinces showed the highest and lowest carbon sequestration, respectively.
    Keywords: Air temperature, residue decomposition, residue retention, soil moisture
  • Vida Varnaseri Ghandali, Parviz Rezvani Moghaddam *, Surur Khorramdel Pages 123-135
    Introduction
    Canary seed (Phalaris canariensis L.) from poaceae family is a drought tolerant plant. Canary seed originally is native to Mediterranean region, and can be grown commercially in several parts of the world.
    Evaluation of different systems of plant feeding to achieve a high yield and desirable quality is one of the important requirements in agricultural planning . Therefore, gradually replacing chemical fertilizers with biological and organic fertilizers will result in providing nutrient requirements of plants, improvement of physical, chemical and biological conditions of soil and reduction of adverse environmental effects. Therefore, the aim of this research is to study the effect of deficit irrigation and managing the use of chemical and organic fertilizers individually or  combined on yield and yield components of canary seed.
    Materials and methods
    To investigate the effects of different levels of irrigation water and integrated management of chemical and organic fertilizers on growth indices, yield and yield components of Canary seed plant, an experiment was conducted as split plot based on a randomized complete block design with three replications at Agricultural Research Station, College of Agriculture, Ferdowsi University of Mashhad, Iran during growing season of 2013-2014.
    Main plots considered different irrigation regimes  with three levels (60, 80 and 100 percent of water requirement) and sub-plots considered for fertilizer treatments in six levels (chemical fertilizer, vermicompost fertilizer, manure, chemical fertilizer + vermicompost fertilizer, chemical fertilizer + manure and control). The amounts of treatment of nitrogen chemical fertilizer (200 kg ha-1 of urea source and 150 kg ha-1 of triple super phosphate) were applied in related plots. The amounts of manure fertilizers (30 t ha-1) and vermicompost (6 t ha-1) were determined and applied based on recommended amount of nitrogen. Water requirement of Canary seed was estimated by the OPTIWAT software under general condition of Mashhad
    Before final harvest of the grain, 10 bushes were randomly chosen from each plot and traits such as bush height, the number of tillers per bush, the number of prolific tillers in each bush, the number of spikes in each bush, the number of grains in each spike, the grain weight in each spike and bush, 1000 grain weight and harvest index were determined. Then, considering margin from a surface equivalent to 1.4 m2, plants were harvested from the height 3-5 cm and the produced biomass in each plot was recorded. Then, grains were separated from straw and the grain yield was determined in each plot.
    Finally, recorded data were analyzed by SAS software ver. 9.1 and mean comparison based on Duncan multiple-range test was conducted by MSTAT-C software in the probability level of 5 percent. 
    Result and Discussion
    This study results indicated that different levels of water irrigation had significant impact on all studied traits except harvest index. All studied traits except harvest index and 1000-grain weight had been significantly influenced by fertilizer treatments. Interaction of different irrigation regimes and fertilizer treatments had significant effect on the traits including plant height, the number of tillers per plant.  The maximum height of plant was observed in irrigation treatment of 80 percent of water requirement and the maximum number of tillers per plant was observed in irrigation treatment of 100 percent of water requirement. In addition, under the irrigation treatment of 100 percent water requirement and 100 percent water requirement, the maximum number of grains per plant and the maximum biological yield was observed.  The maximum grains per plant and biological yield was observed under animal manure and vermicompost treatments. Animal manure and vermicompost treatments had higher yield than control and chemical fertilizer treatments. In most of the studied traits, irrigation treatment of 100 percent water requirement was not significantly different from 80 percent water requirement irrigation.
    Acknowledgements
    The authors acknowledge the financial support of the project (grant number 31441, 09 July 2014) Ferdowsi University of Mashhad, Iran.
    Keywords: Cow manure, Growth indices, Integrated management, Vermicompost, Organic fertilizers
  • A. Koocheki *, M. Nassiri Mahallati, A. Amin Ghafori, M. Mahlouji Rad Pages 137-153
    Introduction
    World population will be increased up to 9 billion and food demand up to 50 percent by 2050. This exponential increase in population, without an associated increase in arable land, in recent years, significantly threaten crop production. Therefore, engineering crop plants in order to achieve greater yields has been a major focus of plant biologists and breeders with a view to ensuring food availability for an increasing world population under changing environmental conditions. Plant performance is strongly associated with, and dependent on, plant development and growth. Several developmental features of plants, such as overall plant architecture, leaf features and vasculature architecture, are major traits that determine the overall performance of crop plants. The importance of plant developmental features in increasing crop yield potential became evident during the ‘green revolution’, when an unprecedented increase in yield was achieved by breeding for semi-dwarf varieties of rice and wheat. Furthermore, due to rapid global environmental changes, restricted land and water resources,  increasing food production particularly for wheat should be achieved mainly by increased crop yield (Koning & van Ittersum, 2009). Yield could be increased by genetic or agronomic measures and understanding the share of each component is of great importance for designing future cropping systems. However, these issues are not fully studied and quantified. Therefore, in this research yield trend of irrigated wheat at national level is analyzed for 1971-2011 period and contribution of cultivar improvement and agronomic management to yield increment have been estimated.
    Material and Methods
    Trends of total production, cultivated area and yield of irrigated wheat were analyzed for the country for 40 years (1971-2011) using linear regression with slope as annual increment rate of each variable. Weather-adjusted yield trend was also estimated based on residuals of regression as described by Nassiri Mahallati & Koocheki (2014a). Share of cultivated area and yield in total production was calculated by using component analysis. Annual changes in yield of irrigated wheat (dY, kg ha-1 yr-1 i.e. the slope of yield trend model) described by Equ.(1): dY = dG + dN + dP + dO (1)
    where dG, dN, dP and dO (all in kg ha-1 yr-1) are annual yield increment due to genetic, N-fertilizers, P-fertilizers and Other agronomic factors. Contribution of genetic factors (dG) was estimated based on the cultivar improvement index (Silvey, 1981). Share of chemical fertilizers (dN and dP) in remaining yield increase (dY - dG) was calculated for each year during the study period. Finally, contribution of other agronomic measures (dO) to yield was estimated by subtracting right hand terms of Equ. (1) from dY.
    Results and Discussion
    Wheat production and yield was increased by 3.2 and 1.4 times over the studied period, respectively. However, cultivated area after a sharp increase at 2.8% per year until 2000 was decreased in the last decade by 1% per year. Annual weather variation showed significant effect on irrigated wheat yield so that averaged over the 40 years, estimated rate of yield increment was 24% lower than weather adjusted yield. During the 4 decades mean contribution of cultivated area and yield on total wheat production were 44 and 56%, respectively and it was estimated that share of yield will be increased up to 70% in the present decade. Genetic yield potential of irrigated wheat cultivars has increased at 57 kg ha-1 yr-1 (1.18% per year) for  the period 1968-2011. During the studied period wheat cultivar improvement contributed to annual rate of yield increment by 34.8% while in the same period average contribution of N and P fertilizers were estimated as 25.4 and 8.8%, respectively leaving 31% for the other agronomic measures.
    Keywords: Cultivar improvement index, Genetic gain, Genetic potential, Trend analysis
  • M. Nassiri Mahallati, A. Koocheki *, A. Ghalehgolabbehbahani, A. Davari, S.S. Moinoddini Pages 155-170
    Introduction[1]
    Biodiversity is a network of all living organisms, including plants, animals, fungi and other living organisms. In fact, biodiversity refers to the diversity of life and the interactions between living organisms. Agricultural biodiversity as a subset of biodiversity refers to the part of biodiversity used by farmers to produce food. It is well documented that conservation of agricultural biodiversity is crucial for maintaining multifunctional characteristics of agroecosystem as a basis for sustainable crop production. Quantification and monitoring the spatio-temporal variations of crop biodiversity are essential elements for the purpose of biodiversity conservation. Such studies, however, with focusing on spatial variability and temporal changes of crop diversity is largely overlooked. On the other hand, recent studies have shown that merely use of traditional measures such as Shannon and Simpson diversity indices may cause misinterpretation of the results. Therefore, using new measures such as species intactness indices would help to find out the amount of intactness in individual or a number of species over a long period of time. Therefore, the main objective of this study was evaluation of changes over time in crop species diversity at regional scale. Furthermore, two new groups of biodiversity indices for quantification of temporal variation of biodiversity are compared with the common diversity indices.  
    Materials and Methods
    In this study, crop diversity intactness and traditional diversity indices were investigated for North, Central (Razavi) and South Khorasan provinces (located at Northeast of Iran). Long‑term data (1983-2008) regarding cultivated area of different crop species within selected cities across three studied provinces were collected from official databases. Time course of crop species diversity was quantified using 3 groups of indices.
    - Traditional indices i.e. species richness and Shannon species diversity index (H'), where H' was calculated on the basis of relative cultivated area of species.
    - Species intactness indices based on occurrence, calculated by the difference between crop species diversity at the reference time (reference diversity) and observed species diversity at any given time.
    - Species intactness indices based on abundance, estimated from the difference between cultivated area (frequency) of crop species at reference time and any given time during the study period.
    Finally, time trend of each group of indices was evaluated using regression analysis.
    Results and Discussion
    Results showed that in three studied provinces both species richness which demonstrates the number of cultivated crop species and Shannon divesity index were increased during the period of 1983-2008. However, Shannon index for Torbate Heydariye, Farooj, Jajarm was decreased over the study period. Although traditional indices showed an improvement of crop diversity over time, they are not able to distinguish the structural changes in the crop species composition. For example if new exotic crop species were introduced, Shannon index would show higher diversity because of higher richness. Intactness indeices of crop species indicated a decreasing trend compare with reference years (i.e. 1983 to 1988), showing changes in crop species composition over the studied period which is in contrast with the results of traditional indices. It is supposed that this discrepancy is due to the crucial change of crop diversity pattern and substitution of some local crops by exotic species and vast expansion of intensive cropping systems across three studied provinces. In fact, in the studied regions, introduction of new exotic crops is led to neglection of some indigenes species.
    Conclusion
    The results of this study indicated that using diversity intactness indices are superior over traditional diversity measures when the objective of the study is evaluation of structural changes in crop species diversity over time . Overall, intactness of crop diversity in three studied provinces was decreased which is seemingly the results of introduction of new crop species and intensification of production systems.
    Keywords: Conventional biodiversity indices, Intactness indices, Intensive agriculture, Monitoring
  • F. Faramarzi, M.S. Taghizadeh*, A. Behpoori, S. Afzali Harsini Pages 171-184
    Introduction[1]
    Weed management is a key issue in ecological management of agroecosystems, and weed control should be tackled primarily by altering the competitive balance between crop and weeds. This can be through measures such as the correct choice of rotation, the choice of crop species and cultivars with more competitive ability and precision nutrient management. The infestation of weeds may also be significantly reduced by crop species diversification in cropping systems. Therefore, intercropping system is one of the ways to diversity. It is likely that intercrops promote the use of the available resources by crops, thus, leaving less opportunity for the establishment and growth of weeds. In addition to cropping system components, the absorption of nutrients may be affected and in some cases be increased by nitrogen. Reduction of available nutrients to weeds is one of the ecological approaches for to weaken weeds and to increase crop yield. This experiment was conducted to investigate the effects of cereals intercropping systems and nitrogen levels on nitrogen and micro-nutrients (Fe, Zn, Cu and Mn) content of weeds shoot and crop grain yield.
    Materials and Methods
    This experiment was carried out at the Darab faculty of Agriculture and Natural Resources, Shiraz University, Iran during 2013-14 cropping season. Treatments were arranged in a factorial experiment based on randomized complete block design (RCBD) with three replicates. Treatments were five different sowing ratios of wheat: triticale consisted of 100: 0, 75: 25, 50: 50, 25: 75, 0: 100, four different sowing ratios of barley: triticale consisted of 100: 0, 75: 25, 50: 50, 25: 75 and two nitrogen levels (100 and 200 kg N ha-1). Nitrogen and micro-nutrients (Fe, Zn, Cu and Mn) content of weeds shoot and grain yield were measured and compared statistically.
    Results and Discussion
    The lowest and the highest nitrogen content of weeds shoot was observed in the monoculture of triticale with 200 kg N ha-1 and in the monoculture of wheat with 200 kg N ha-1 respectively. The interaction of intercropping systems and nitrogen levels led to decrease of nitrogen content in weeds tissue. There were the lowest Fe and Mn content of weeds shoot in W50T50 and B50T5050 intercropping systems with 200 kg N ha-1. The W25T75 and monoculture of barley (B100) showed the lowest Zn content for weeds shoot and increasing nitrogen fertilizer resulted in an increase in Zn content of weeds. The Cu content of weed shoot was higher in monocultures than that in intercropping systems. The lowest Cu content in weeds shoot was observed in W50T50 and B75T25 where 100 kg N ha-1 applied to the experimental plots. Furthermore, grain yield in wheat: triticale intercropping was greater than that in monoculture of wheat. In this study, B50T50 cropping system with 200 kg N ha-1 showed the highest grain yield. Generally, grain yield of crops increased with rising nitrogen amount in intercropping systems.
    Conclusion
    The results of this study showed that nitrogen, Fe and Mn content of weeds shoot decreased where they grew in intercropping systems with the highest nitrogen fertilizer level. However, Cu content of weeds shoot decreased in intercropping systems and lower nitrogen fertilizer level. Furthermore, Zn content of weeds shoot decreased in intercropping systems and high amount of nitrogen fertilizer increased this micro-nutrient in weeds shoot. According to the results, crop grain yield increased significantly (P≤0.01) where a higher amount of nitrogen fertilizer applied to cereal intercropping systems. These findings have implications for ecological management of weeds in cropping systems and increasing crop yield through increasing cereal crop diversity and management of nitrogen and micro-nutrients (Fe, Zn, Cu and Mn).
    Keywords: Copper, Iron, Manganese, Triticale, Wheat, Zinc
  • A. Esmaili, M.R. Tadayon * Pages 185-198
    Introduction[1]Most of the food for the world comes from some 150 plant species cultivated as crops. Sugar (the common name for sucrose) is obtained from only two crops, cane and beet. Sugar cane has been produced in large quantities in tropical regions for many centuries and continues to dominate the world supply of sugar. In contrast, sugar beet is a relatively new crop, appearing in temperate regions in the nineteenth century and spreading widely only in the twentieth century. Sugar beet is now grown in some 50 countries and provides about a quarter of the 140 Mt sugar currently used each year. In a world with increasing demand for water, and where agriculture consumes most of the available fresh water, the problem of how to maintain or increase agricultural productivity with sustainable use of water resources is an enormous challenge. Drought is a major limitation and the most significant environmental stress to crop productivity worldwide. This stress is the most important and common abiotic factor that limits sugar beet production in semi-arid regions and also in some parts of Europe. Due to putting Iran in the arid and semi-arid and climate, it is essential to study the effects of water stress on plant growth. In the last decade, the impact of drought has been recognized as a major cause of yield losses in sugar beet. Humic substances play a vital role in soil fertility and plant nutrition. Plants grown on soils which contain adequate humic acid are less subject to stress, are healthier, produce higher yields; and the nutritional quality of harvested foods and feeds are superior. Humic acid can be directly, have positive effects on plant growth. Shoots and roots growth is stimulated by the humic acid, but its effect on the roots, is more prominent, root volume and the effectiveness of its root system will increase by humic acid.
    Materials and Methods
     In order to study the effect of drought stress and humic acid on sugar beet an experiment was conducted as split plot in randomized complete block design (RCBD) base at Research Station of Shahrekord University in 2013. The main factor including: irrigation treatments (100%, 85%, 70% and 45% FC) and sub factors were humic acid at four levels (0, 2, 4 and 6 kg ha-1). Before planting seeds were disinfected with benomyl fungicide. Then planting was conducted in 10 plants m-2 density. Irrigation treatments was applied 40 days after sowing (unfolding of third trifoliate leaf) and continued in the growing season. Humic acid application was performed at three stages inclusive 4th, 8th and 16th leaf formation. Shoot dry weight, leaf area index, root diameter, root yield, sugar content, pure sugar percentage and molasses percentage was recorded. Data from these experiments were analyzed by analysis of variance using t-Student test for LSD calculation and are described as significant at the P < 0.05 level.
    Results and Discussion
    Shoots weight showed increasing trend at all treatments, but application of water restriction treatments reduced shoot weight. At all levels of irrigation and concentrations of humic acid, leaf area index showed an increasing trend until mid-season and then a gentler slope than the first half of the growing season began to fall. Deficit irrigation reduced root diameter but humic acid application increased it. Humic acid application increased root yield and increase the amount of humic acid, also increased the root yield. So that, highest root yield was recorded from of six kg.ha-1 humic acid treatment and the lowest root yield was obtained from the treatment of not using of humic acid application at each level of irrigation. Root yield in 85%, 70% and 45% of field capacity decreased by 4.2%, 11.3% and 18.2% respectively, while application of 2, 4 and 6 kg.ha-1 humic acid increased root yield by 416%, 84.8% and 110 % respectively. Application of 2, 4 and 6 kg.ha-1 humic acid reduced molasses percentage by 2.9%, 1.4% and 12.9% respectively.
    Conclusion
    Application of humic acid enhances the root yield so that treatments 2, 4 and 6 kg per hectare humic acid, increased root yield by 41.6, 84.8 and 110.5 percent respectively.
    Keywords: Leaf area index, Pure sugar content, Root yield
  • G. Ahmadvand *, S. Hajinia Pages 199-215
    Introduction
    Water stress is one of the most important limiting factors in crop production, especially in arid and semi-arid regions. More than 45% of agricultural land on earth is subjected to continuous or frequent water deficiency, and it can cause ~50% loss of grain yield, on average. Soybean growth is affected by drought stress. Drought stress has been estimated to reduce seed yield of soybean by 24 to 50 percent. Improvement the light absorption in the crop plant increase the crop yield. All plants, at least during their vegetative growing period, produce and store dry matters using sunlight. One of the most important strategies to increase tolerance to dehydration and improve the growth performance in crops is to establish associations with the beneficial of fungal symbiosis. Piriformospora indica is one of the cultivable root-colonizing endophytic fungi that has a symbiotic relationship with the roots of most crops and improves the growth and yield of plants by increasing the absorption of nutrients such as phosphorus and some micro- elements and can enhance the resistance to biotic and abiotic stresses (Oelmuller et al., 2009). The aim of the present investigation was to study the impact of P. indica on the light absorption, radiation use efficiency and grain yield of soybean under different levels of irrigation.
    Materials and Methods
    Two field experiments were carried out at the Agricultural Faculty, University of Bu-Ali Sina, Hamedan, Iran (35º1ʹN, 48 º31ʹE; 1690 m a.m.s.l.) in 2014 and 2015. This region has a cold and semi-dry climate. The experiments were carried out as split-plot based on a randomized complete block design with three replications. The Main factors consisted of three irrigation treatments (irrigation after 60 (well-watered), 90 (mild stress) and 120 (severe stress) mm cumulative evaporation from pan class A) and sub plots included of two levels of fungus P. indica (inoculated and non-inoculated). All main plots were irrigated immediately after sowing. Water-stress treatments as described above were applied after seedling establishment. Irrigation was performed via polyethylene pipes, and a water meter was used to measure the volume of irrigation water in each main plot. In order to maintain the specified soil-moisture regimes, the amount of used water was calculated by using crop water requirement as described by Doorenbos and Pruitt (1992).
    Results and Discussion
    In both years, drought stress decreased leaf area and dry matter of soybean. Inoculation with fungus, increased leaf area and dry matter of soybean plants in different irrigation levels. Daneshian et al. (2011) studied the effect of drought stress on dry matter and soybean growth indices. Due to the decrease in leaf area, drought stress reduced the amount of dry matter accumulation in the soybean plants. The highest radiation use efficiency (1.75 and 1.85 g MJ-1 in 1st and 2nd year, respectively) was obtained from inoculated soybean plant under well-watered, and the lowest one (1.10 and 1.15 g MJ-1 in 1st and 2nd year, respectively) was observed in control plant (non-inoculated) under severe drought stress. Drought stress reduces the amount of radiation use efficiency by reducing photosynthetic rates and decreasing leaf area index. Severe drought stress significantly decreased grain yield of soybean by about 57.20 percent. Application of P. indica caused an increase in grain yield of soybean by about 13.67, 22.85 and 22.14 percent under well-watered, mild and severe drought stress, respectively, compared to control (non-inoculate). Inoculation with P. indica fungus increases the light absorption and radiation use efficiency by increasing the amount of vegetative growth, leaf area index and photosynthetic material production, which improves the yield of soybean.
    Conclusion
    The results showed P. indica fungus had a positive effect on absorption and radiation use efficiency of soybean in different irrigation levels, so that the application of fungus mitigated the effects of drought stress and improved the yield of soybean under drought stress.
    Keywords: Endophytic fungus, Irrigation, Photosynthetic active radiation, Radiation use efficiency
  • K. Kaboosi*, O. Majidi Pages 217-229
    Introduction
    Wheat has strategic importance in Iran and Golestan province is one of the major regions of wheat production in the country. Province has the third place among all provinces of the country in term of wheat cultivated lands (about 400 thousand hectares) and grain production (more than one million tons). The optimal planting date for any crop normally occur within a sowing window. It is defined as beginning and end of the planting period which guarantee the achievement of reasonable yield. In rainfed farming, farmers face a decision of whether or not to plant when sufficient rainfall accumulates to increase soil moisture content. If the average meteorological data is used to design a farming system, such as planting date, its probability will be 50 percent. Average rainfall data (50 percent probability level) are quite unreliable for cropping planning. Usually, risk levels of 60 to 80 percent are recommended depending on the sensitivity of the crop to water stress, acceptable risk by farmer and soil. Therefore, it can be stated that in rainfed cultivation, farmers choose their risk based on the selection of the planting date. Considering the importance of predicting the appropriate planting date in optimizing farm management in rainfed farming and its dependence on the occurrence of autumn rainfall on the one hand and the stochastic nature of rainfall, on the other hand, the present study was conducted to determine the sowing window of wheat in the Golestan province at different occurrence probability levels.
    Materials and Methods
     Initially, by reviewing the geographic distribution of meteorological stations in Golestan province and their statistical period, daily rainfall data of 58 meteorological stations in the 1991- 2016 period (26 years) were gathered. Then, suitable planting date of wheat in each station and year was determined based on the first rainfall date equal to or more than 25 mm over a period of 10 consecutive days in October. In the next step, suitable planting date for each station was calculated by the occurrence probability level 25, 50, 75, 85 and 95 percent based on statistical analysis and choose the best probability function using the software SMADA. Verification of zoning maps was done based on findings of field scale researches. Finally, in the meantime of statistical analyzing the results, zoning maps of suitable planting date of rainfed wheat were prepared using ArcGIS software by Inverse Distance Weighting (IDW).
    Results and Discussion
     The results showed that the suitable planting date of rainfed wheat in the southern half of the Golestan province was earlier than the northern part. The occurrence probability level had a significant effect on suitable planting date but the effect of the station was not significant. The statistical difference between all occurrence probability levels was significant, so that the occurrence probability level of 25 and 95 percent indicated the earliest and bottommost suitable planting date of rainfed wheat in Golestan province, respectively. Within different stations of the province, the suitable planting dates of rainfed wheat for 25, 50, 75, 85 and 95 percent occurrence probability were between 22 November to 1 December, 22 November to 13 December, 24 November to 3 January, 2 December to 15 January and 12 December to 20 January, respectively. Increasing the occurrence probability levels prolonged the sowing window so that the difference between suitable planting dates in different stations was 10 and 40 days for 25 and 95 probability level, respectively. According to the results, a small reduction in the risk of farming (an increase in the occurrence probability level of suitable rainfall from 25 to 50 percent) is possible with a delay in planting date for a few days, while a greater reduction in the risk (an increase in the occurrence probability level of suitable rainfall to 75, 85 and 95 percent) will be possible through a delay of the planting date for several decades. Verification and validation of the results of this study based on findings of field scale researches confirmed the accuracy of predicting the suitable planting date by autumn rainfall.
    Conclusion
    The results showed that the farmers of the Golestan province with the correct understanding of the role of autumn rainfall in crop growth and yield and based on their experimental knowledge, selected the appropriate planting date of rainfed wheat with a high probability level.
    Keywords: Delayed Planting, Risk, Sowing Window
  • R. Nazarian, A. Koocheki*, M. Nasiri Mahallati, P. Rezvani Moghaddam Pages 231-243
    For optimize of cropping rate and pattern in a mixture of barley (Hordeum vulgare L.) and persian clover (Trifolium respinatum L.) an experiment was arranged in split plot with randomized complete block design and three replications. This experiment was conducted on research farm of the Faculty of Agriculture, Ferdowsi University of Mashhad in 2013-14. The pattern of sowing considered in five levels (row intercropping 1:1 (M1), row intercropping 2:2 (M2), strip intercropping 3:3 (M3), strip intercropping 4:4 (M4) and mixed cropping (M5)) in main plots and the cropping rate were in five levels (barley %100: %50 clover (R5), barley %100: %25 clover (R4), barley %50: %50 clover (R3),with pure barley (R2) and pure clover (R1)) in subplots. ). Results showed that the effect of cropping rate and pattern on forage dry matter (FDM) and protein yield (PY) were significant (P<0.01). The highest levels of forage dry matter were obtained in pure barley R2 (14731 kg/ha) and mixed cropping M5 (12857.9 kg/ha), respectively. The highest protein yield were also obtained in R2 (1962.2 Kg/ha) and M5 (1584.38 Kg/ha). The effect of sowing pattern on land equivalent ratio (LER) was not significant but the effect of cropping rate was significant (P <0.01). The highest levels of LER were obtained in R5 (1.28) and M4 (1.23), respectively. The effect of sowing rate and pattern on relative crowding coefficient (RCC or K) was not significant but the highest level of K was obtained in R4 (35.33) and the lowest was in R5 (-23.24). The effect of sowing rate and pattern on aggressivity (A) was significant, and the clover negative value of aggressivity (A) showed that the clover was recessive in intercrop. Economic indices such as actual yield loss (AYL) and intercropping advantage index (IA) showed that barley-clover intercropping was better than sole culture, and the highest IA was obtained in R4 (7,262,833 Rials) and M4 (4974840 Rials).
    Keywords: Cropping pattern, Cropping rate, Land equivalent ratio (LER), Additive mixture, Replacement mixture
  • J. Hamzei*, R. Davoudian Pages 245-259
    Introduction
    One of the ecological strategies for increasing of stability is diversity creation by multiple cropping. So, intercropping is an advantage approach for utilization from environmental resource in comparison with monoculture. Intercropping, which is defined as growing two or more species simultaneously in the same field during a growing season, has been considered as an important strategy to develop sustainable production systems, particularly those which aim to limit external inputs such as chemical fertilizer and herbicide. Intercropping is a sustainable cropping practice that has been successfully implemented in agroecosystems. In 79% of biodiversity experiments, biomass production in species diverse systems was on average, 1.7 times higher than in monoculture. Biodiversity enhancement can increase productivity and other ecosystem functions through replacement and complementarity effects. Complementarity effects occur when intercropped plants with complementary traits interact positively to increase productivity, and here genuine yield gains are possible. Thus, it was aimed to evaluate the agrophysiological traits, and yield of canola intercropped with chickpea in different plant densities.
    Materials and methods
     Ecophysiological aspects of chickpea-canola intercropping were assessed at the Agricultural Research Station, Faculty of Agriculture (latitude 35◦34'N, longitude 50◦57'E), University of Tehran, during 2014 growing season. The area lies at an altitude of 2010 m.a.s.l. The mean annual rainfall was 256 mm. The mean maximum and minimum temperatures were 27.5°C and 8°C, correspondingly. The soil type of the experimental site was clay loam with pH of 7.78. Irrigation of the entire experiment was done with an overhead sprinkler system on a weekly basis until soil had reached field capacity. Experiment was done as factorial layout bases on a randomized complete block design with three replications and eight treatments. Treatments were sole cropping of rapeseed (60 and 80 plants m-2; 60R and 80R), sole cropping of chickpea (30 and 40 plants m-2; 30C and 40C) and additive intercropping based on combination of the two species (30C+60R, 30C+80R, 40C+60R, 40C+80R). The crops' seeds were sown simultaneously. Leaf chlorophyll reading was measured in the youngest expanded leafs using an SPAD-502 (Minolta). The Photosynthetic CO2 assimilation was measured with a portable leaf chamber and an open-system infrared gas analyzer (IRGA). At the final harvest, plants were cut at ground level and seeds were separated by manual threshing. Grain productivity was used to calculate land equivalent ratio (LER). LER was calculated to measure efficiency of intercropping compared to pure cropping (Banik et al., 2006). SAS vs. 9.1 procedures and programs were used for analysis of variance (ANOVA) calculations. Least significant differences (LSD) test was use for means comparison at 5% probability level.
    Results and discussion
    Results indicated that chlorophyll reading and protein percentage for canola in intercropping treatment with chickpea were more than its sole cropping. However, photosynthetic rate for both species in sole cropping was more than intercropping. The highest canola grain yield (370.7 g m-2) was achieved at sole cropping with 80 plants m-2 but this treatment had not significant difference with canola sole cropping with 60 plants m-2. Also, chickpea sole cropping in comparison with intercropping treatments had higher grain yield. Although, grain yields of canola and chickpea at sole cropping treatments decreased in comparison with intercropping, but evaluation of land equivalent ratio (LER) confirmed higher advantage of intercropping. At all of the intercropping treatments, LER was higher than one and the highest value for LER (1.46) was revealed at ‘30 plants m-2 chickpea+60 plants m-2 canola’ treatment. In fact, when the value of land equivalent ratio is less than 1, the intercropping affects the growth negatively and yield of crops grown in mixtures but when the value of LER is more than 1, the intercropping favors the growth and yield of the crops. Moreover, the total land equivalent ratio was higher in intercropping system compared to the sole cropping system, indicating the advantage of intercropping over sole cropping in utilizing environmental resources for crop growth.
    Conclusion; In general, chickpea/canola intercropping had relative advantage in comparison with sole cropping and increased land use efficiency. So that, results indicated that intercropping of medium density of chickpea (30 plants m-2) with medium density of canola (60 plants m-2) may give better overall yield and income than sole cropping of canola and chickpea.
    Acknowledgments
    We would like to thank the funding from Faculty of Agriculture, Tehran University, Iran.
    Keywords: Grain legume, Land equivalent ratio, Multiple cropping, Oil seed, Photosynthetic
  • P. Nazeri, A.H. Shirani Rad *, S.A. Valad Abadi, M. Mirakhori, and E. Hadidi Masoule Pages 261-276
    Introduction
    Development of new canola (Brassica napus L.) varieties need effective tools to monitor characterizes association in yield and its components. Although, determination of the response of canola cultivars to environmental variables is one of the principal of agriculture planning to achieve maximum qualitative and quantitative yield. Drought stress and planting date are the most important factor which limit yield production in arid and semiarid regions. Iran is considered as the arid and semiarid with average rainfall of 250 mm. On the other hand, 33% of agricultural land is devoted to dry cultivation. Changing plant date will change yield and product quality by affecting on vegetative and reproductive growth period and balance between them.
    Materials and Methods
    In order to study the responses of four winter canola cultivars to late season drought stress and different planting dates on physiological, morphology characteristics and yield, a split factorial experiment was carried out in Randomized Complete Block Design with three replication in 2011-2012 in Karaj province. Planting date in two levels, normally sowing dates and delayed planting date and irrigation in two levels, normal and cutting off irrigation from pod stage to next, both in main plot and four cultivars included (Trapper, Makro, Smilla and Agamax) in sub plot. Drought stress was applied by control of irrigation during the pod lengthening stage. Thus, drought was applied by withholding water when the first pod appeared at the beginning of pod filling (April 27th). At this stage, chlorophyll and total sugar solution content was measured as index of drought stress damage. Eleven traits were measured on 10 random plant/plot at physiological maturity stage (June 24th). The traits were plant height, no. of branches/plot, number of pods /plant, pod length, number of seeds/plant,1000-seed weight, seed yield, biomass yield, oil percentage, oil yield and harvest index.
    Results and Discussion
    The results showed all characteristics except harvest index, significantly (p≥0.05) were influenced by planting date, drought and cultivars. Interaction of sowing date in irrigated was significant in attributes of soluble carbohydrates, plant height, number of pods per plant and oil content. The triple effect was significant only in the concentration of soluble carbohydrates. Due to late planting and irrigation disruption, increasing in soluble carbohydrates and reducing the concentration of chlorophyll was occurred. The yield components of canola decreased because of delays in planting and irrigation disruption which leads to lower grain and canola oil yield. Among cultivars, two cultivars Trapper and Agamax narrowly to each other had better outperformed comparing to Smilla and Marko. Using different sowing dates can change the time of plant growth and development, helping the plant to survive better, under the stress of heat and drought. Water stress along with end of the season delayed planting, reduces yield components and increasing concentrations of soluble carbohydrates. Non-significant interaction effects of planting dates and cultivars for seed and oil yield indicated that yield reduction of the cultivars in late planting dates had similar trend. Drought not only causes dramatic loss of pigments but also leads to disorganization of thylakoid membranes. Therefore reduction in chlorophyll contents is expected. The sowing date may influence plant growth that can be attributed to the favorable climatic conditions (rain and temperature).
    Conclusion
    Correlation between drought tolerance and yield in all cultivars, identify the most suitable indicators for monitoring drought tolerance cultivars. According to these results, Trapper and Agamax can be recommended for semiarid regions due to maximum seed and oil yield among the stress and non-stress condition. Delayed planting decrease seed oil percent, grain and oil yield of Smilla and Makro than the other cultivars.
    Keywords: Canola, Chlorophyll, Delayed planting, Yield, component yield, Water deficit
  • A. Gorjizad, A. Soltani, S. Dastan *, H. Ajamnoroozi Pages 277-294
    Introduction
    Rice (Oryza sativa L.) is the staple food of more than half of the world’s population and has an obvious effect in feeding, income and job creation of people in the world especially, Iran. The rice cultivation area in the world during the past years has been from 145 million hectares to over 160 million hectares. The last global statistics showed that paddy yield and white rice production were 742 and 492.2 million tons respectively in 2014. The same amount is predicted for 2016. Yield gap analysis is providing a little estimation of increased production capacity which is one important component in designing food providing strategy in regional, national scale and world-wide surface. Due to the existing anxiety about discussions of food security, studies are also increasing globally and in Iran is necessary to estimate the quantity of yield gap and the reasons behind it by appropriate statistical methods, or in other words, detecting the restricting parameters of potential yield. As it was mentioned several factors prevent farmers to reach attainable yield in many crops. It seemed that by defining the effectiveness of each management parameters on the amount of presented yield gap and consequently farmer’s knowledge on that matter, the distance between actual yield and attainable yield can be reduced. In this research estimation of potential yield, yield gap and determining yield restricting factors and each of their portions in creating yield gap is investigated.
    Material and Methods
    The research was done in 100 paddy fields between the Alborz Mountains range and the Caspian Sea in 2016. In this research, all managerial operations from nursery preparation to harvest for modified rice cultivars were recorded through field studies in Neka, Mazandaran, Iran from 2015-2016. All farm cases are pertaining to improved cultivars. The improved rice cultivars were Shiroodi, Neda, Fajr, Ghaem, Khazar, and Nemat, respectively.
    Field identifications were done in a way that includes all main production procedure in a specific region with variation in management viewpoint. For defining the yield model (production model), the relationship between all measured variables and the final model was designed by controlled trial and error method. The final model was obtained through the controlled trial and error method, which can quantify the effect of yield limitations. The average paddy yield was calculated by the model by placing the observed average variables (Xs) in the fields under study in the yield model. Thereafter, by putting the best-observed value of the variables in the yield model, the maximum obtainable yield was calculated. The difference between these two has been considered as yield gap. Different procedures of the software SAS version 9.1 were used for analysis.
    Results and Discussion
    Data analysis revealed that seed consumption was varied from 30 to 120 kg.ha-1. The range of seedling age variable was from 20 to 60 days old. In 100 paddy fields planting density were 16 to 40 plants per m2. Nitrogen usage by 26% of farmers was among 69 to 92 kg.ha-1 and 16% of the farmers consumed 92 to 115 kg N per hectare. Potassium application was varied from 0 to 100 kg K ha-1 which within 60% of the field’s potassium usage was less than 35 kg K ha-1. The range of paddy yield in 100 paddy fields was varied from 6100 to 8200 kg.ha-1 that in 40% of the studied fields, the paddy yield was from 7000 to 7600 kg.ha-1. In the CPA model, the paddy yield increasing related to the effect of N top dressing, K usage and N usage after flowering was 327, 674 and 324 kg.ha-1.
    Conclusion
    Therefore, the actual yield and yield potential were estimated to be 7194 and 9241 kg.ha-1, respectively and the yield gap was 2047 kg.ha-1. Therefore, regarding the fact that calculated potential yield was reached through actual data in each paddy field, it has been stated that this yield potential is attainable.
    Keywords: Attainable yield, CPA, Documentation, Management factors, Rice
  • E. Mohammadi *, H.R. Asghari, A. Gholami, S. Khorramdel Pages 295-307
    Introduction
    Conventional tillage systems disturb the soil in the long term and obstruct farmland sustainability. Hence, adoption of conservation tillage systems, for example no tillage and reduced tillage has been widely accepted in the last two decades.
    The use of chemical fertilizers has increased in intensive farming systems, but this brings with environmental problems. Nowadays, due to the problems of chemical fertilizers, the use of organic fertilizers such as manure and biochar has been more prevalent in agriculture. Biochar is the product of incomplete combustion of biomass in the absence of oxygen. Its presence in the soil is reported to improve physical and chemical properties and crop yield.
    Materials and Methods
    In order to evaluate the effect of nutrition management on yield and yield components of corn (Zea mays L.) under different tillage systems, a field experiment was carried out at research farm of Shahrood University of Technology in 2015. The experiment was conducted as a split plot arranged in a randomized complete block design with three replications. The main plots were tillage systems (conventional tillage and reduced tillage) and subplots were control, chemical fertilizer (300 kg.ha-1 urea and 100 kg.ha-1 triple superphosphate), manure (20 t.ha-1), biochar (20 t.ha-1), chemical fertilizer + manure (150 kg.ha-1 urea and 50 kg.ha-1 triple superphosphate and 10 t.ha-1 of manure), chemical fertilizer + biochar (150 kg.ha-1 urea and 50 kg.ha-1 triple superphosphate and 20 t.ha-1 biochar) and manure + biochar (20 t.ha-1 biochar and 10 t.ha-1 of manure). After adding manure, biochar and triple superphosphate, corn was planted on 10 days and urea was used in stages three. At full maturity 10 plants were randomly selected and the biological yield, grain yield, 100-grain weight, ear weight, number of row per ear, number of grains per row, ear length, ear diameter, height and stem diameter were measured.
    Results and Discussion
    The results showed that the effect of tillage systems and the interaction of tillage systems and nutrient management were not significant on any of the measured traits. Tillage systems affect yield mainly by altering water and nitrate content in soil. The water content and nitrate concentration in the soil had no significant difference between tillage systems (data not shown). As well as tillage systems are site-specific, so the degree of their success depends on soil, climate and management practices. The nutrition management had significant effect on grain nutrients, grain protein, ear characteristics, 100-grain weight, biological yield, grain yield and harvest index. The highest and lowest grain nitrogen, ear weight, biological yield and grain yield were obtained in chemical fertilizer and control, respectively. The chemical fertilizer + manure increased grain nitrogen, ear weight, biological yield and grain yield 13.89, 56.19, 47.04 and 60.41 percent compared to the control, respectively. As well as chemical fertilizer + biochar increased grain nitrogen, ear weight, biological yield and grain yield compared to control 14.81, 52.78, 42.69 and 56.32 percent, respectively. Crops respond to nitrogen fertilization mainly by increasing aboveground and root biomass production. As a result of increasing nitrogen doses, the photosynthetic activity, leaf area index (LAI) and leaf area density (LAD) increase. Providing organic matter and nutrients create better conditions for photosynthesis and plant growth. The increased maize yield in biochar amended soil could be attributed to increased nutrient availability and to improved soil physical properties indicated by decreased soil bulk density.
    Conclusion
    Based on results, the effect of nutrition management was significant on height, stem diameter, grain nutrients, grain protein, ear characteristics, 100-grain weight, biological yield, grain yield and harvest index. Maximum and minimum of stem diameter, grain nitrogen, grain protein, ear characteristics, 100-grain weight, biological yield, grain yield and harvest index were obtained in chemical and control, respectively. Although using of chemical fertilizer had the highest amount of traits, it had no significant difference with chemical fertilizer + manure and chemical fertilizer + biochar. Also, there were no significant effect between conventional tillage and reduced tillage. Therefore, due to the excessive use of nitrogen fertilizer and also due to the negative effects of conventional tillage on the physical, chemical and biological properties of soil, it can be concluded that use of reduced tillage and chemical fertilizer + manure and chemical fertilizer + biochar for corn production is recommended for similar conditions with the study area to reduce both chemical fertilizer and environmental pollution.
    Keywords: Biochar, Conventional Tillage, Grain protein, Grain yield, Manure, Reduced tillage
  • D. Rasouli *, R. Mohammadpour Vashvaei, B.A. Fakheri Pages 309-320
    Introduction
    Ammi visnaga (L.) Lam is a herbaceous medicinal plant and belongs to Umbelliferae family. It is native to the Mediterranean region. A. visnagais well known as a source of essential oil and is especially cultivated for it therapeutic properties (diaphoretic, carminative, antispasmodic, antiseptic, tonic,) being used in traditional medicine systems in many countries. Essential oil of A. visnaga is known for its proprieties against coronary diseases and bronchial asthma. Phenolic compounds considered as a kind of bio-regulators which are synthesized in the environmental conditions in plant cells. These compounds are involved in various processes of plant growth and reproduction as well as a defense mechanism against biotic and abiotic stresses. Amino acids as bio-regulators have been identified as an alternative to chemical fertilizer to increase soil fertility and crop production in sustainable farming. Therefore, the main objective of the present field experiment was to investigate the effects of bio-regulators on morphological and physiological traits and essential oil of A. visnaga.
    Materials and Methods
    A factorial experiment was performed based on a randomized complete block design (RCBD) at Agricultural Research Institute of Zabol University in 2014-15. The experiment was conducted in pots with a height of 20 cm and a diameter of 33 cm. The treatments used in this study consisted phenolic compounds (salicylic acid, trans-cinnamic acid and benzoic acid with three levels of 5, 10 and 20 mg l-1) and amino acids (phenylalanine and tyrosine with three levels of 50, 100 and 200 mg l-1). Distilled water was used as control. All treatments were applied by foliar application and spraying was done 30 days after planting. Measurement was performed at maturity stage (210 days after planting) and fruiting (180 days after planting). The measured traits include vegetative growth characteristics (plant height, branch number, umbel number, fresh weight of herb and dry weight of herb), relative water content (RWC), photosynthetic pigments (Chl a, Chl b, carotinoids, Chl a+Chl b and (Chl a+Chl b)/carotinoids), carbohydrate (total carbohydrates, soluble carbohydrate, insoluble carbohydrate), Fruit yield, essential oil content and yield. For identifying the essential oil components, essential oil fraction was collected and subjected to GC/MS (Gas Chromatography-Mass spectrometry) analysis. Analysis of variance by using SAS software and mean comparisons by Duncan’s multiple range test (at the 5% probability level) was done.
    Results and Discussion
    The results indicated that bio-regulators significantly affected on all of the traits.  In addition, benzoic acid 20 mg l-1 had the greatest impact compared to other treatments so that, vegetative growth characteristics 46.2 percent, RWC 60.2 percent, photosynthetic pigments include Chl a 77.6, Chl b 60.6, carotinoids 66. 7, Chla+Chl b 73.3 and Chl a+Chl b/carotinoids 19.1percent were increased compared to control treatment. After extraction type and amount of volatile compounds were determined in the aerial part of A. visnaga with GC-MS. Dominant compounds of essential oil in this plant were included 2, 2-dimethylbutanoic acid, isobutyl isobutyrate, thymol and croweacin. In this study, all treatments on the green tissues of A. visnaga were increased the essential oil content. The results of this study demonstrated that, the use of bio-regulators, with aimed at reducing the use of chemical fertilizers, had a positive effect to increase the quality and quantity of A. visnaga and also, sustainable production and environmental protection.
    Conclusion
    The results of this study demonstrated that, the use of bio-regulators, with aimed at reducing the use of chemical fertilizers, had a positive effect to increase the quality and quantity of A. visnaga and also, sustainable production and environmental protection. Considering the importance of the production of medicinal plants in farming systems, bio-regulators such as phenolic compounds seem to be a viable alternative to chemical fertilizers in the production of these plants.
    Keywords: Amino acids, Bio-regulators, Essential oil, Phenolic compounds
  • N. Aghaeipour, H. Pirdashti *, M. Zavareh, H. Asadi, M.A. Bahmanyar Pages 321-334
    Introduction
    Nowadays, identification of the yield limiting factors in the field particularly the various yield components including number of panicle per unit area, number of seeds per panicle and seed weight) is one of the most important methods to increase the production of rice. The yield gap (YG) analysis can be performed by measuring the yield related characteristics. Yield gap was estimated as the difference between actual and potential yield that has been used in various studies as an important indicator to increase the yield in crops and different areas. One of the most powerful methods to evaluate the reasons of yield potential and yield gap is boundary line analysis. The purpose of this research was to select an appropriate function for describing the relationship between yield and yield components in the Fumann plain of Guilan province. Furthermore, after selecting the superior function, the parameters of the yield and yield components were estimated  to calculate the yield gap in the region.
    Materials and Methods
    The present study was carried out during two cropping seasons: 2012-13 and 2013-14 in Foumanat plain (cv. ‘Tarom Hashemi’). We recorded the geographic coordinates of 53 fields. At the end of growing season (harvesting time), paddy yield and yield components (panicle number, filled grain number and 100- grain weight) were calculated in each field. The correlation coefficients between yield components and yield were studied. Segmented, quadratic and dent-like models were applied to describe the relationship between yield and yield components. Root mean square error (RMSE), determination coefficient (R2), regression simple coefficients (a & b) and coefficient of variation (CV) were used to identify the appropriate model. After selecting a superior model, the boundary line method was used to calculate yield gap and its percentage, optimum yield and optimum amount of yield components for each field.
    Results and Discussion
    According to the results, a positive and significant correlation was existed between paddy yield with panicle number and filled grain number with 100- grain weight and a negative and significant correlation was existed between 100- grain weights with panicle number. Linear regression simple coefficients for all traits studied in the quadratic function and for two traits of panicles number per square meter and of filled grains number in the panicle in the segmented model were significant. Among the fitted models, segmented model has the lowest RMSE (respectively equal to 0.082 and 0.472) and coefficient of variation (equal to 1.26 and 6.39, respectively) in terms of two characteristics of panicle number and 100- grain weight and was able to describe the trend of the experimental data. In addition, dent-like model with the lowest RMSE (equal to 0.484) and coefficient of variation (equal to 6.60) used to describe the changes of filled grain number. In Foumanat plain, YG was recorded 3.63 t.ha-1with the average optimum yield and actual yield of 8.44 and 4.81 t.ha-1, respectively (40% reduction in yield). Also, the optimum amount of panicle number, filled grain number and 100- grain weight were 560, 47-83.9, and 2.18 g, respectively.
    Conclusion
    Although, the area of Foumanat plain in the west of Guilan province has low actual yield, there is a good potential to increase the current yield. In this study, two segmented and dent-like models were identified as superior models. The highest YG in this study was related to the number of panicles per square meter followed by the number of filled grains and the 100- grain weight. Therefore, proper crop management for improving the yield components could be an important step towards reducing the YG and increasing the yield potential in the studied area.
    Keywords: coefficient of variation, dent-like model, non linear regression, panicle number, segmented model
  • Z.Hosseini, H.Feizi *, S.Vatandoost Jertodeh, M.Alipanah Pages 335-347
    Introduction
    The basis for plant breeding research is genetic variability. In fact, without access to such variety, plant breeders to create and deliver new varieties will not have much success. Mirzaee Nadushan (2001) evaluated different species of mint and its morphologic features. In this study, between different species, a significant difference in terms of characters such as plant height, stem diameter, number of branches, leaf length and width were observed. Horse Mint (Mentha longifolia syn. Mentha sylvestris) is a valuable medicinal and aromatic plant belong to Lamiaceae family. The aim of this study was to identify areas of distribution, determine the ecological and morphological assessment of various climates and yield valuable medicinal oil is such that it provides a basis for investigating the genetic diversity of germplasm.
    Materials and Methods
     In order to study morphological characteristics of Mentha longifolia in 10 regions of Fars and Khorasan Razavi Province, sampling was done at flowering stage in summer 2015. In order to study morphological diversity of wild landraces in Fars and Khorasan Razavi by referring to reliable sources, including Flora Iranica area distribution and habitats of this plant was found in two Provinces. The study area includes five sites in Fars Province (Sepidan, Bavanat, Fasa, Kovar, Kazeroon) and five regions in Khorasan Razavi Province (Torbat Heydarieh, Mashhad, Nishabur, Kashmar and Chenaran). Given that most of the active ingredients of the plant at the time of flowering is reported, plant samples in full bloom in ten regions in Fars and Khorasan were taken. Some samples were selected from each region and 19 quantitative and qualitative characteristics were determined for each ecotype. For accurate identification and diagnosis of morphological Horse mint herbarium specimens were collected and identified samples was done by qualified personnel. For extract the essential oil by water distillation by Clevenger apparatus according to the Pharmacopoeia Great Britain for three hours were done.
    The samples based on all the characteristics of using the SPSS software and Ward methods were grouped. All correlation coefficients of traits in populations that were collected were analyzed by Pierson method using SPSS software. Cluster analysis was performed using JMP software.
    Results and Discussion
    The results showed considerable diversity in terms of morphological characteristics among ecotypes. Most of the side branch was observed in Mashhad and Kashmar populations. Correlation analysis showed significant positive association between some important characteristics. The correlation coefficients showed a positive association between the length of flower and length and width of leaf. Principal components analysis showed that traits like leaf length, width and blade tip were placed in first factor and had the most allotment in describing changes among collected data. Cluster analysis divided the subjects into four distinct groups. Mentha average production efficiency review showed that the highest essential oil yields was in Mashhad sites (1.8) and site of Kashmar (1.8) and the lowest amount of oil from the habitat Chenaran (0.9). Due to the high yields of essentials in samples collected from Mashhad district, it can be considered it is a good place prone to extraction of essential oils among studied areas.
    Conclusion
    The correlation coefficients showed a positive correlation between the length of flower and length and width of leaf. The shortest length of flowering branch inflorescence and the status of being in the seventh factor 46.5% of the change can be justified. The highest essential oil yields in Mashhad (1.8) and site of Kashmar (1.8) and the lowest amount of oil from the habitat Chenaran (0.9) was shown. Finally Mashhad landrace suggested for selection in domestication and cultivation of this plant.
    Acknowledgment
    The study was sponsored by the University of TorbatHeydarieh which thereby is appreciated
    Keywords: Cluster analysis, Diversity, Medicinal plants, Morphological traits
  • A. Soltan Ahmadi, A. Nezami *, M. Kafi, H. R. Khazae Pages 349-364
    Introduction
    Tall festuca (Festuca arundinacea) belongs to Poaceae family and is a cool-season perennial plant native to Europe. Festuca species are broadly adapted to different climate conditions. To date, 9 different species of Festuca have been identified in Iran. These species are growing naturally in different regions of Iran such as Golestan, Mazandaran, Lorestan, Khorasan, Fars, Isfahan, Karaj, Dorood, Damaneh, Alvand and Firoozkooh. Festuca reduces soil erosion due to its fibrous, thick and deep roots. Such roots reduce soil density and improve soil structure and reduce soil erosion, and thus, this plant plays a crucial role in reducing water and wind erosion. Tall fescue is a long-lived perennial species with medium to large leaves. The plant is grown as turf and is considered as an important animal fodder, thus is widely grown in pastures and grasslands. Tall festuca is among the 27 identified species of festuca in Iran. The species is well spread across Iran and has a high potential for growth and production in pastures or mountainous areas, especially in the central, western and northern regions of the country. Tall festuca is a perennial plant, so it is often exposed to cold and freezing stress. Therefore, the successful production of this plant requires the use of cold-tolerant varieties. According to previous studies, although tall festuca has good tolerance to a wide range of environmental stresses (cold and drought), different ecotypes show different cold tolerance, accordingly further studies on growth characteristics and cold tolerance of this plant is necessary, especially in winter type varieties.
    Materials and methods
    The field experiment was carried out in Parks and Green Space Organization, Mashhad Municipality located in the Islamic Republic of Iran Blvd., and Crop Physiology Laboratory, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran in 2013- 2014. The experimental design was a randomized complete block design arranged in a split plot with three replicates. In order to expose the tall festuca plants to winter cold stress, 23 ecotypes were sown on the 7th of October and 6th of November. Dimensions of each plot were 100 × 150 cm and after seed sowing, seeds were covered with composted cattle manure and then irrigated. After emerging the seedlings, the plots were thinned to reach final plant density of 400 plants per square meter. Weeds were manually controlled and irrigation was carried out according to the need of the plants. The data were analyzed using MSTAT-C. The comparison of means was performed through the LSD test at 5% probability level.
    Results and discussion
    The results showed that the effects of sowing date and ecotype were significant on a number of days until emergence, survival percentage, plant dry weight, seed yield, and total dry weight. The phenological investigations and plant height measurement indicated that there was a genetic difference between the ecotypes. In all studied ecotypes, the survival percentage in the second sowing date was higher than that in the first sowing date. However, a number of days until emergence, plant dry weight, seed yield and total dry weight in the first sowing date were found to be higher in comparison to tens second sowing date. In addition, among the studied ecotypes, the highest traits stability with an emphasis on survival percentage and yield components were observed in Isfahan, Boroujen, Daran, Daran-Damaneh, Gandoman, Sanaajan, Mashhad, Sari, Golestan, and Quchan-Seyyed Abad ecotypes. Therefore, these ecotypes were selected as genetic reserves for future studies.
    Conclusion
    In general, the effect of sowing date and ecotype was significant on most of the studied traits such as a number of days until seedling emergence, survival percentage, plant dry weight, seed yield, and total dry weight. In addition, in phenology related traits such as a number of days from flowering to maturity, total growing period length and plant height genetic difference between ecotypes was investigated. Although in most of the traits such as a number of days until seedlings emergence, plant dry weight, seed yield, and total dry weight, the obtained values were higher in the first sowing date compared with the second sowing date, survival percentage showed unlike results so that late sowing increased this index.
    Keywords: Plant height, Sowing date, Survival Percentage, Seed yield, Phenological Stages