Effect of Nitrogen on Critical Period of Weed Control in Sunflower (Helianthus annuus L.) in Birjand Region
Message:
Abstract:
In order to study of nitrogen effect on critical period of weed control in sunflower (Helianthus annuus L.) in Birjand region, a split plot experiment based on randomized complete block design was conducted with 24 treatments and 3 replications in research farm of college of agriculture of Birjand University in 2010. The main factor was three levels of nitrogen (0, 100 and 200 Kg.ha-1) and the sub factor was different weed competition periods containing of three levels of weed free, 3 levels of weed infested until phonological stages of V2, V4 and VR with two control (all season weed free and weed infested) treatments. The critical periods of weed control based on 5%, 10% and 15% of acceptable yield loss, were estimated by fitting of Gompertz and Logestic functions to driven data of respective yield of sunflower in weed free and weed infested treatments respectively. Results showed that increasing of weed infested period and decreasing of weed free periods, increased weed dry weight but decreased their density. The most weed dry weight and competition and so the least yield of sunflower was observed in 100 Kg ha-1 nitrogen. So, the longest period of weed control was obtained at this level of nitrogen fertilizer. The critical periods of weed control based on 5% of acceptable yield loss were 1-66, 3-91 and 2-76 DAE for 0, 100 and 200 Kg ha-1nitrogen, respectively
Language:
Persian
Published:
Journal of plant protection, Volume:26 Issue: 1, 2012
Page:
64
magiran.com/p1009328  
دانلود و مطالعه متن این مقاله با یکی از روشهای زیر امکان پذیر است:
اشتراک شخصی
با عضویت و پرداخت آنلاین حق اشتراک یک‌ساله به مبلغ 990,000ريال می‌توانید 70 عنوان مطلب دانلود کنید!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی نامحدود همه کاربران به متن مطالب تهیه نمایند!
توجه!
  • حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران می‌شود.
  • پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانه‌های چاپی و دیجیتال را به کاربر نمی‌دهد.
دسترسی سراسری کاربران دانشگاه پیام نور!
اعضای هیئت علمی و دانشجویان دانشگاه پیام نور در سراسر کشور، در صورت ثبت نام با ایمیل دانشگاهی، تا پایان فروردین ماه 1403 به مقالات سایت دسترسی خواهند داشت!
In order to view content subscription is required

Personal subscription
Subscribe magiran.com for 50 € euros via PayPal and download 70 articles during a year.
Organization subscription
Please contact us to subscribe your university or library for unlimited access!