نشریه بوم شناسی کشاورزی
سال دوازدهم شماره 2 (تابستان 1399)

Modern agricultural systems have adverse effects on environmental aspects of production and ecosystem health. Loss of biodiversity due to monoculture is one of these adverse consequences. Biodiversity and agriculture are strongly interrelated. While biodiversity is critical for agriculture, sustainable use of biodiversity corresponds to agricultural structure and function, and thus is an indicator for farming practices. Indeed, biodiversity is considered as a vital component of sustainable agriculture from the food security, nutrition, and livelihoods viewpoints. Agricultural expansion and intensification led to biodiversity loss in agroecosystems and reduction in the types and levels of ecosystem services (ES) that people benefit from. Considering the importance of biodiversity in sustainable agricultural systems and variability of agroecosystems in Zanjan province, the goal of this study was biodiversity assessment of crop and horticultural products in this province.

Agrobiodiversity research, of Zanjan province was evaluated at the county level and it was classified to two groups; agronomy and horticulture. For this purpose necessary data for assessment of biodiversity indices, including cropping area and types of crop and horticultural species for eight county in Zanjan province were obtained from Jihad Agriculture Management of these counties, statistics and information center, statistical report of Jihad Agriculture Ministry, and interviews with experts, managers and farmers during 2016. All crude data entered to excel program and then, some biodiversity such as Shannon, Simpson, Berger-Parker, Sorenson's similarity, uniformity, total number of species and the total number of individuals in all species were calculated according to their equations. Data analysis was performed by Excel var. 2010 and Canoco softwares.

The results showed that the highest and lowest values of Shannon index were calculated in Khoramdarah (2.14) and Khodabandeh (0.87) countiesin crop products section, respectively. Also, in the garden products section, the highest and lowest amounts of this index were related to the Tarom (0.99) and Khoramdar (0.62) counties, respectively. In terms of Simpson's index, the highest amount was obtained in Khoramdar county for crop products section (0.83) and Tarom county (0.81) for horticultural products section. The Berger-Parker index had the highest value in Khodabandeh (0.80) and Khoramdarah (0.79) countiesrelated to crops and horticultural products, respectively. According to the Sorenson similarity index for crops products, the highest similarity was found between Abajrood and Abhar, also, the highest level of similarity was found between Zanjan and Mahneshan for garden section. In assessment of the biodiversity indicators with the climatic condition of the Zanjan province, it was determined that in crops products, the biodiversity affected by precipitation and relative humidity, but in the horticultural products, it was strongly influenced by the minimum temperature and relative humidity. The variability of Shannon and Simpson were related to relative humidity, minimum, maximum and average annual temperatures in crops production section, but, these indicators were more related to maximum and average annual temperatures in garden products section. The results of this study indicated that biodiversity indices for some townships were not favorable in Zanjan province.

The diagram of the analysis redundancy (RDA) showed that the most biodiversity indicators were more correlated with maximum temperature and relative humidity among crops and gardens products.These results indicated that biodiversity has decreased in many regions and it was reached to lowest value. From this viewpoint, we have to understand the ability of biodiversity to support ecosystems such as agroecosystems and sustainable agriculture ecosystem by providing numerous services. Therefore, educating and encouraging farmers to use of crops types can improve the biodiversity services for suitability of agricultural systems in Zanjan province.

We are thankful to Jihad Agriculture organization of Zanjan province, and Gorgan University of Agricultural Sciences and Natural Resources (GUASNR) for all their companions and supports.

Forage millet is a crop of tropical and subtropical regions which is considered due to abundant tillering, rebuilding ability, resistance to environmental stresses and diseases, high yield in poor soils and absence of prussic acid. Low amount of available water to plants results in drought stress and inappropriate morphological and physiological changes in the plant. Plants under environmental stress conditions accumulate low molecular weight organic solutions such as amino acids and sugars. Plant hormones affect plant growth in multifarious ways affecting a number of physiological and biochemical processes in plants subjected to biotic and abiotic stresses. Salicylic acid (SA) is one such plant growth regulators, which participates in the regulation of a number of physiological events in plants. The use of salicylic acid in wheat increased the photosynthesis rate, protein and sugar content of shoots, roots and leaf chlorophyll under drought stress conditions. Tomato and amaranth treatment with salicylic acid in different stages of growth during drought stress prevents reducing the production of dry matter of the plant.

To evaluate the quantity and quality fodder traits of foxtail millet Bastan cultivar under the influence of drought stress levels and salicylic acid concentrations in Sistan climate, a field experiment was conducted as split plot based on a randomized complete block design with three replications at the Agricultural Research Institute of Zabol University during 2017. Treatments included three irrigation levels as main plot (45, 65 and 85 percent humidity of field capacity) and sub plot including salicylic acid in four levels (0, 0.75, 1.5 and 3 mM). Spray application was considered for salicylic acid. Dry forage yield, dry matter digestibility, water soluble carbohydrates, crude protein, crude fiber, insoluble fiber in acid detergent, insoluble fiber in neutral detergent and ash were measured. Measurement of forage quality characteristics in the Research Institute of Forests and Rangelands was performed with NIRS device made in Sweden.

Results revealed that drought stress caused significant differences on dry forage yield, dry matter digestibility, water soluble carbohydrates, crude protein, insoluble fiber in acid detergent and insoluble fiber in neutral detergent at 1% significance level and on ash at 5% significance level. Drought stress increases water soluble carbohydrate, insoluble fiber in acid detergent and insoluble fiber in neutral detergent and decreases dry forage yield, dry matter digestibility, crude protein, crude fiber and ash. The effect of salicylic acid on dry matter digestibility, water soluble carbohydrates, crude protein, crude fiber and insoluble fiber in acid detergent at 1% significance level and on dry forage yield and insoluble fiber in neutral detergent were significant at 5% level. The interaction effects of drought stress and salicylic acid on dry forage yield, dry matter digestibility, water soluble carbohydrates, crude protein, crude fiber, insoluble fiber in acid detergent and insoluble fiber in neutral detergent were significant at 1% probability level. Maximum dry forage yield (12.34 t.ha-1), dry matter digestibility (68.85%) and crude fiber (40.79%) were obtained from full irrigation and application of 3 mM salicylic acid treatments. The highest water soluble carbohydrates (13.81%) and crude protein (18.93%) were obtained from intense tension × 1.5 mM salicylic acid and control× 1.5 mM salicylic acid, respectively. The highest insoluble fiber in acid detergent (41.31%) and insoluble fiber in neutral detergent (81.51%) were observed under severe drought stress conditions without salicylic acid.

The results of this study represent the adverse impact of drought stress on the quantity and quality traits of foxtail millet Bastan. Application of salicylic acid has a positive role in modulating the effects of drought and improves quantity and quality forage. Therefore, can be expressed that irrigation of 85% moisture filed capacity and spraying 3 mM salicylic acid as growth regulator can produce quantity and quality desirable performance in Sistan climatic conditions.

Intercropping due to better use of environmental resources, has led to this type of agronomic system in livelihoods farming having an important role in providing food and has a special place in the design of sustainable agro-ecosystems. The superiority of yield in intercropping cultivation is due to the combination of various factors such as better use of soil moisture, light and nutrients. Organic fertilizers such as vermi compost and animal manure lead to improve the performance of plant by increasing the availability of moisture and nutrients available to plants, and consequently increase soil organic matter. Considering the importance of suitable cropping pattern and determining the optimal feeding systems agricultural systems, the current study aimed to evaluate intercropping systems of Roselle and cowpea with organic fertilizers and the introduction of best cultivation model as well as the optimal amount of fertilizer. The experiments were carried out in the Sistan region.

In order to investigate the effects of vermicompost and cow manure on morphological characteristics in Roselle and cowpea, the experiments conducted at the Research Institute of Zabol University during growing season of 2016. Treatments experiment included three levels of organic fertilizers as the main plot including cow fertilizer (30 t.ha-1), vermicompost fertilizer (15 t.ha-1) and control as well as 5 levels of intercropping patterns including (100% Roselle, 100% cowpea, 50% Roselle+ 50% cowpea, 25% Roselle+ 75% cowpea and 75% Roselle+ 25% cowpea). As subplot agent, from the middle of each plot five plants were harvested randomly at the end of the growing season to determine yield. Finally, data analysis was performed using SAS version 9.1. Comparison of mean treatments was performed using Duncan's multiple range test at 5% probability level. Irrigation was performed every day (7 days) on average according to the requirement of both plants. Relative performance of each component was calculated to calculate the Land Equivalent Ratio (LER).

The results of variance analysis showed that the interaction of organic fertilizers and intercropping except for the traits of stem height and chlorophyll content (a,b) of cowpea, is significant for all traits measured Roselle and cowpea. The highest dry sepal yield Roselle (1170.58 kg.ha-1) was obtained in vermicompost and 50% Roselle and 50% cowpea and highest Seed yield of cowpea (2418.3 kg.ha-1) was for vermicompost+ cowpea 25%+ Roselle 75%. The use of organic fertilizers improves vegetative growth and yield components by releasing nutrients gradually. Intercropping is useful when the yield of the intercropping product is greater than the maximum single craft product. Yield increment can be attributed to the better use of the available resources by the two plants, the morphological differences between them and the lower weed in the intercropping system. The results showed that plant systems have a significant effect on the Land Equivalent Ratio (LER). The highest LER (5.37) of Treatment Vermicompost+ cowpea 25% + Roselle 75%, showed the advantage of intercropping over sole crop. Concerning the superiority of intercropping to sole crop, it can be argued that increasing yield is due to increased resource efficiency in intercropping system.

In the present study the highest sepal yield of Roselle was obtained in intercropping system with vermicompost with 50% Roselle and 50% cowpea and highest seed yield of cowpea was observed in intercropping system with vermicompost with cowpea 25%+ Roselle 75%. The results of the experiment indicate that the performance of both species was influenced by different ratios of cultivation and fertilization. Intercropping cultivation in Roselle and cowpea is much more profitable than single cultivation, because of the significant and beneficial interactions that make use of environmental resources (such as water, nutrients, and sun light).

Cumin (Cuminum cyminum L.) is one of the most important domestic herbs in Iran and is one of the earliest spices used by humans. Due to its characteristics such as short growing season, low water requirement, non-interruption of growth season with other agricultural products as well as high economic justification for other crops and export, it has found a special place in arid and semi-arid areas, including Sabzevar. Growth, yield and characteristics of medicinal plants are influenced by environmental factors such as temperature and light that can be varied by different sowing dates. Planting date is one of the most important factors in crop performance improvement and percentage of essential oil of cumin, which is resulted in weather parameters changes during the growing season and then in the production. In addition, the use of the adapted ecotype to the environmental conditions of the area plays a major role in achieving a proper performance. A high proportion of the total variation in yield is related to the interaction of genotype in planting history, which can greatly complicated the choice for a broad adaptation to different sowing dates. This research was carried out with aim of investigating the changes in yield of cumin ecotypes in different planting dates and determining the optimum planting time for this plant under Sabzevar climatic conditions.

In order to investigate the effect of planting date on quantitative and qualitative characteristics of different cumin populations, field experiment was conducted as split plots in a randomized complete block design with three replications in Sabzevar, Iran during 2016-2017. The factors included sowing date at three levels: 30 January, 20 February and 10 March, as well as different cumin ecotype in four levels of Sabzevar, Birjand, Kerman and Biyarjomand, respectively, assigned to the main plots and sub plots, respectively. Plant height, Umbel per plant, Seed per umbels, 1000- Seed yield, Biological yield, Essential oil yield and Essential oil percentage were measured and calculated accordingly. The treatments were run as an analysis of variance (ANOVA) to determine if significant differences existed among treatments means. Multiple comparison tests were performed for significant effects using the Duncan,s test.

The results showed that the highest number of umbels per plant, plant height, 1000-seed weight, seed yield and biological yield, as well as percentage of essential oil were obtained in the sowing date of January 30, and the delay in planting reduced the qualitative and quantitative characteristics of cumin. Among the studied ecotypes, Sabzevar ecotype had the highest number of umbrellas per plant, plant height, biological yield and essential oil percentage, as well as the highest number of seeds per umbels, seed yield and essential oil in Sabzevar ecotype and at sowing date of 30 January. It turned out that Sabzevar ecotype seems to have shown significant superiority to other ecotypes with higher potential performance in the studied environment. In this research, linear relationship between essential oil percentage and yield, as well as seed yield and essential oil yield were observed with 96% and 93%, respectively.

The optimum cumin’s planting date in one region causes reduction of the effects of non-biotic stresses during the growing season. The results of this experiment showed that in winter crop cultivation, seed yield and essential oil significantly decreased by delayed planting from January to March. In addition, Sabzevar ecotype in the study area had higher production potential. As for sowing date, the highest seed yield and essential oil were obtained in the first and second month of sowing. It seems that planting of cumin in the January increases the production potential due to increasing growth period and absorption of photosynthetic active radiation, as well as more effective use of plants from environmental factors.

The use of organic fertilizers such as vermicompost is a major component of organic farming practices. Vermicompost can provide the essential plant nutrients and enhance crop productivity, but also leave a beneficial residual effect on succeeding crops. Intercropping is the cultivation of two or more crops in such a way that they interact agronomically. Intercropping legumes with non-legumes is particularly important in organic farming because it enhances yield stability, concentrations and uptake of nutrients and on the other hand reduces disease and weed pressure. There is no information available about the effects of fertilizer source in intercropping system on the ecophysiological characteristics of linseed and chickpea in dry conditions. Therefore, the purpose of the present study was to contribute to a better understanding of the eco-physiology responses of linseed and chickpea plants to fertilizer source and cropping pattern.

The field experiments were conducted at Agricultural Experimental in a farm located in Naqadeh, West Azerbaijan, Iran (longitude 45°24' E, latitude 38°52' N, altitude 1318 m) in 2017. The first factor included six cropping patterns consist of 1 row chickpea + 1 row lineseed, 2 rows chickpea + 2 rows linseed, 4 rows chickpea + 2 rows linseed, 2 rows chickpea + 4 rows linseed and monocropping of each crop and the second factor was included four levels control (no use fertilizer), 100% chemical fertilizers (NPK), biofertilizers (Azoto Barvar -1+ PhosphateBarvar -2+ PotaBarvar-2+ Sulfur Barvar -1) and vermicompost (10 t.ha1-).  In order to measure different elements in seed of linseed and chickpea, dry ash method was used. Concentration of potassium (K) was analyzed by a flame photometer. Nitrogen measurements by Kjeldahl and phosphorus were calculated by yellow method, in which vanadate–molybdate is used as an indicator. Phosphorus (P) content was determined at 430 nm using a spectrophotometer. To measure the microbial respiration of the soil, the Anderson and Dumasuch methods were used and microbial biomass carbon was determined by fumigation- extraction method.

Chickpea: According to the results of the experiment, intercropping and fertilizer source had a significant effect on improving nutrients uptake of linseed and chickpea plants. The highest amounts of chlorophyll a, chlorophyll b and carotenoids were obtained from 1 row chickpea + 1 row lineseed and four row chickpea + two rows of lineseed, respectively and the lowest amount was related to sole cropping. The results of fertilizer treatments showed that the highest amounts of chlorophyll a and chlorophyll b and carotenoid were obtained from vermicompost treatment and the lowest amount of these photosynthetic pigments was obtained in non-fertilized conditions. In addition, the results showed that nutrients uptake were affected by cropping pattern and fertilizer treatments. Among the fertilizer treatments, the highest percentage of nitrogen and phosphorus in chickpea were achieved from vermicompost fertilizer and these values were obtained from control treatment.Linseed: Mean comparison of data showed that photosynthetic pigments were affected by different fertilizer treatments. So that the highest amounts of chlorophyll a, chlorophyll b and carotenoids were obtained from vermicompost treatment and the least amount of these photosynthetic pigments were achieved from control treatment. Among the applied fertilizer treatments, the highest amount of phosphorus and potassium were obtained from biofertilizer treatment and the lowest values ​​were recorded from control (non-usage of fertilizer. Soil microbial respiration and microbial soil biomass were only affected by cropping patterns and fertilizer source. The highest Soil microbial respiration and soil microbial biomass were recorded in two rows of chickpea + two rows of linseed with vermicompost application.

The use of fertilizer source plays an effective role in increasing the uptake nutrients of chickpea and linseed, which is probably due to the supply of water and improved activity of beneficial microorganisms in the soil. Soil respiration and microbial biomass increased under the influence of fertilizer treatments (both biofertilizer and organic fertilizer), however the activity of soil microorganisms was the main reason for the increased soil respiration under application of vermicompost fertilizer.

CO2 is considered the most important greenhouse gas, due to the dependence of world economies on fossil fuels. CO2 concentration are enhancing in the last decades, mainly due to the increase of anthropogenic emissions. Carbon dioxide capture is a technology aimed at mitigating greenhouse gas emissions from burning fossil fuels during industrial processes. Conservation tillage, crop rotation, and crop residue management are agronomic practices that potentially decrease CO2 and other greenhouse gas emissions from agriculture. Crop residues also improve organic matter decomposition due to declined soil-residue contact. Soil is one of the significant “friends” in combating climate change and global warming, and a zero-soil consumption approach is the best way to stop adverse effects, although it is not the only one that should be applied. The soil has been considered as a possible carbon sink for sequestering atmospheric CO2.
Our purposes were to determine a set of coefficients for calculating conversion coefficients, dry weight, organic carbon, and carbon sequestration of above-ground and below-ground tissues and assess global warming potential (GWP) for wheat as an essential crop in Khorasan-e Razavi province.

A systematic random sampling method was employed to select five samples from 25 fields situated in Khorasan-Razavi Province, Iran, during 2016 and 2017. The experimental design was a completely randomized design with three replications. Below-ground tissues by using a cylinder were manually sampled and then separated from the soil. After sampling, the above-ground tissues (such as flower and leaf) were isolated from below-ground tissues (including tunic and corm) to measure the above-ground and below-ground biomasses, respectively. Above-ground and below-ground biomasses were separately dried to constant weight and expressed on a dry matter basis. Conversion coefficients of above- ground and below- ground tissues were determined with the combustion method separately. Then, sequestration carbon potential for above- ground and below- ground tissues of saffron and soil were computed. The ash method was used to determine the conversion coefficients in spikes, stems, leaves, and roots. Finally, greenhouse gases (such as CO2, N2O, and CH4) emission were also calculated using emission coefficients. Cronbach's alpha was used for assessing the reliability of the questionnaire.
For statistical analysis, analysis of variance and Duncan’s test were performed using SAS version 9.3.

The results showed that dry weight, organic carbon content, conversion coefficients, and carbon sequestration for above- ground and below- ground tissues of wheat were significantly different. The biomass of above-ground tissues was higher than below-ground tissues of wheat. The results revealed that the maximum (52.0%) and minimum (31.99%) conversion coefficients of wheat were related to spikes (seeds included) and roots, respectively. Besides, the total carbon sequestration of below-ground and above-ground of wheat was calculated 8.25 t.ha-1 so that the maximum (4.28 t.ha-1) and minimum (0.35 t.ha-1) values were found in stems and roots, respectively. GWP was recorded as 8884.86 kg CO2-equiv. per one ton of seed.

This study shows that while there is significant potential for sequestering carbon in wheat agroecosystems through root and straw incorporations. It is recommended that returning wheat crop residues to the soil affected the soil's physical, chemical, and biological properties. Furthermore, as nitrogenous fertilizer application plays a crucial role in increasing GWP, thus it is suggested that organic fertilizers and legumes might be suitable alternatives for chemical fertilizers. It is therefore concluded that the application of crop residues in agroecosystems seems to be a rational ecological approach for sustainable management of wheat agroecosystems with a consequence of the reduction in greenhouse gases and mitigation of climate change. This could make a significant contribution to improving agricultural sustainability and stability in arid and semiarid regions.

Rice (Oryza sative L.) is an essential crop among cereals and shared a significant component in the global human diet, especially in developing countries. About 80% of water consumption in Asia is for the agriculture sector, and half of it would be used for rice production. Rice needs roughly 8000 to 1000 m3 of water per hectare and 1Kg of its dry matter needs to 700 liters of water. Rice farmers tend to keep their farms flooded continuously to make sure the product is more productive by too much water storage and, in this way, prevent against weeds. Up to the year 2050, rice production should increase by 50%, which requires improved cultivars and enhanced field management. For achieving high crop yield, applying fertilizers to maintain high soil fertility is quite necessary. Nitrogen is one of the main crop’s nutrient requirements and is a limiting factor for rice production. Nitrogen fertilizer affects the accumulation of dry matter and its allocation in different parts of the plants. The difference in the accumulation of dry matter in response to nitrogen arises from the difference in the amount of active radiation received by photosynthesis of vegetative canopy and plant efficiency in the use of solar radiation. Nitrogen deficiency reduces leaf growth, and leaves become less colorful since the amount of chlorophyll in the leaves decreases, accelerates aging leaves, therefore, reduce the amount of solar radiation, and it reduces the accumulation of dry matter in plants, finally. Nitrogen, plays an important and direct role in the development of grains by increasing the level of enzymes and enzyme activity, and this increases the transfer and processing of sucrose to seeds. Many studies have shown that increasing nitrogen up to a threshold has highly increased rice grain yield. Growth analysis indices are essential to realize how the crop yield may change in response to management and environmental factors. Therefore the application of appropriate management factors that have a positive effect on growth indices can enhance grain yield.

This study was conducted as split-plot based on a randomized complete block design in Rice Research Center of Rasht in 2014-2015 and 2015-2016. Irrigation with five levels (daily irrigation, rotational irrigation with 5, 8, 10, and 15 days interval) as main plot and nitrogen at six levels (0.0, 30, 45, 60, 75, and 90 kg.ha-1) as subplot were considered in this experiment. At flowering and harvest leaf and dry stem matter was measured. Then leaf area index (LAI), Crop Growth Rate (CGR), Net Assimilation Rate (NAR), Leaf Area Ratio (LAR), Relative Growth Rate (RGR) and Specific Leaf Area (SLA) were calculated.

Our results showed that the interaction of irrigation and nitrogen significantly (P≤0.01) affects stem and leaf dry matter, LAI, and NAR. Irrigation was significantly (P≤0.01) effective on CGR. Among irrigation levels, daily irrigation resulted in the highest LAI and NAR. Our results indicated that daily and every five days irrigation and considering almost no difference between 75 and 90 kg.ha-1 nitrogen, then 75 kg.ha-1 urea can be suggested as the optimum fertilization value. However, at higher irrigation intervals, 90 kg.ha-1 nitrogen would be recommended. Daily irrigation and 90 kg.ha-1nitrogen showed the highest water consumption (6663 m3.ha-1), but 15 days irrigation interval and 0.0 kg.ha-1nitrogen showed the lowest water consumption (4691 m3.ha-1). It seems that low rate release nitrogen fertilizers, along with suitable irrigation practice, would be the optimum management to achieve high yield and lowest possible irrigation water consumption.

The results of this study showed that applying nitrogen and irrigation increased LAI and crop productivity indices, which resulted in higher biomass yield production. Among irrigation levels, daily irrigation resulted in the highest LAI and CGR. Under daily irrigation and five days of interval irrigation, the application of 75 kg.ha-1 nitrogen can be recommended. Although there was not a significant difference between 70 and 95 kg.ha-1 nitroge, but due to environmental concerns, 75 kg.ha-1was recommended.

Climatic variation particularly for participation is a constraint for the crops to reach their potential productivity under rainfed conditions. Therefore soil moisture preservation by means of tillage practices and improvement of soil physical criteria, particularly through enhancement of organic matter content is crucial. For this reason soil tillage must be managed in a proper way in order to fulfill this objective. Use of the right implements for this purpose under rainfed conditions together with retention of crop residue are practices most suitable for low rainfall environments. Tillage operation has a great impact on soil properties such as soil particle stability, soil aggregate and also soil water holding capacity. There are good evidences regarding yield improvement under rainfed conditions when implements such as chisel plow and sweep plow is used. Reduced tillage has been referred to as a proper practice under such conditions and degrees of no to minimum tillage have been proposed. These types of tillage combined with retention of crop residue which is referred to as conservation agriculture is being received more attention for the sake of soil conservation and moisture preservation. The purpose of the present study was to investigate these type of management for a rainfed wheat-fallow rotation.

In order to study the effect of different tillage practices in fallow-wheat rotation and retention of crop residue on soil properties such as bulk density, soil aggregate, porosity, particle stability and moisture holding capacity and also crop criteria including yield, above ground biomass of wheat and weed under rainfed conditions, an experiment was conducted for two years (2013-2014 and 2014-2015 growing seasons) in Shirvan region, Northeast of Iran. The layout of experiment was strip plots based on a randomized complete block design and three replications. Tillage systems and retention of crop residue were the experimental factors with four levels of tillage (chisel, sweep, moldboard and no tillage) and three levels of crop residue retention (7, 3.5 t.ha-1 and zero residue). Tisdal and Oades method used to determine the soil aggregates size distribution in dry and wet sieving conditions. To determine the soil bulk density, undisturbed samples were picked up from a depth of 0-10, and 10-20 cm and soil bulk density were determined after drying of soil in Oven for 48 hours at a temperature of 105°c. In order to evaluate the soil moisture at the end of the fallow year, sampling was done from each treatment in the depth of 0-20cm. During growth and after harvesting, the plant height, ear length, seed number per ear, thousand kernel weight, seed yield, and biological yield were determined.

Results showed that in general soil bulk density was higher at the depth of 0 to 10 cm compared with that at the depth of 0 to 10 cm for the experimental soil. Soil porosity followed a reserve trend of that of bulk density. Retention of crop residue caused a slower bulk density and a higher soil moisture content. Tillage with moldboard at different levels of crop residue retention caused lower weed biomass compared with other tillage operation. Soil practices size higher than 0.5 mm were respectively higher and lower with moldboard plow. Seed yield and also above ground biomass were higher with moldboard plow compared with the conservation tillage practices. Despite lots of reports about the prominence of conservation tillage systems in comparison with moldboard tillage, the reason for the prominence of moldboard plow in comparison with conservation tillage in this experiment can be attributed to better seedbed preparation in moldboard tillage. The other reason for seed yield increment in the treatment of moldboard tillage in comparison with other treatments can be the effective control of weed plants, especially Russian Knapweed.

Despite contradictory reports about the effect of moldboard tillage on wheat yield in comparison with conservation tillage, the results of this experiment showed the prominence of moldboard tillage in contrast with the sweep, chisel, and no-tillage for wheat production. Under rainfer conditions retention of crop residue together with minimum level of soil disturbance seems to be a proper practice. This has been evidenced elsewhere and is confirmed somehow in our experiment too. This is mostly related to enhancement of water holding capacity of the soil.

It is accepted that the global annual average temperature has been increased during recent decades. The climate of Iran is also affected by this global warming. Some studies indicated the increasing of mean annual temperature of Iran between 3.5-4.5○C by 2050. Crop phenology is directly related to temperature, so climate change could significantly change the phenology and yield of crops. Modelling phenology is a way to simulate the timing of phenological stages based on climatic factors. Amongst models, WOFOST is known as a powerful model for simulation of phenological stages and yield of wheat. In this study climate warming of Iran was evidenced. Based on this fact, trends of potential grain yield and time of flowering and maturity of wheat were studied in different climatic zones of Iran during 1992-2012. It is expected that understanding the thermal induced of phenological changes, can lead us to better field management decision making.

Weather data of 18 cities from 4 climatic zones of Iran (northern warm and humid (Zone 1), southern warm and dry (Zone 2), temperate (Zone 3) and cold and high elevation (Zone 4)) were analyzed during 1992-2012 and the long-term trends of air temperature were detected by linear regression. The crop growth simulation model WOFOST, was used to simulate the time of flowering and maturity and also the potential grain yield of winter wheat. Calibration and validation of model was conducted in 4 selected cities from each zone using statistical measures. The consequences of temperature on duration of grain filling period and also yield of wheat were determined.

Results indicated that the mean annual air temperature was significantly increased in all cities during 1992-2012. The highest increasing rate (regression line slope) belonged to Ardabil (0.159○C.y-1) and the lowest rate was observed in Pars Abad Moghan (0.06○C.y-1). Validation of WOFOST in 4 selected cities from each climatic zone, showed the perfect ability of model in simulating the flowering and maturity time of wheat. Regression analysis showed that the grain filling period was increased in accordance with temperature rise in zone 1 and 4 whereas it was shortened in zone 2 and 3. Grain yield showed the same trends predicted for grain filling period in different climates. Slop of linear regression between temperature and yield was significant except in Gorgan (Zone 1). In all cities the relation between grain filling period and yield was direct and positive.

Although temperature has increased in all climatic zones of Iran, flowering and maturity time and grain yield of wheat has showed different responses. There was a nonsignificant slope of regression line in the north humid climate, which means that the humidity of northern part of Iran (south of Caspian Sea) enhanced stability for this area. Annual mean temperature in southern warm and dry zone of Iran ranged between 24.3-27.9 ○C that could be stressful for wheat, and hence resulted in shorter grain filling period and less grain yield. It seems that in temperate zones (such as Mashhad) increasing temperature caused yield reduction due to faster GDD accumulation and lack of time to complete remobilization of photosynthetic materials. On the other hand, in cold areas increasing temperature could reduce the risk of cold stress in flowering time, resulting in longer grain filling period and higher grain yield. According to WOFOST simulation results, during 20 years study (1992-2012), mean potential yield of wheat increased 6.25 and 11.42 percent in northern warm and humid (Zone 1) and cold and high elevation (Zone 4), respectively and decreased 12.17 and 13.11 percent in southern warm and dry (Zone 2) and temperate (Zone 3), respectively. Total mean potential yield of wheat, by consideration of proportion of each zone in total wheat production of Iran, showed reduction of 1.8% and 3.28% during 1992-2001 period (10 years) and 1992-2012 period (20 years), respectively.          

Durum wheat (Triticum turgidum L. var durum) consist of only 5% of the world’s total cultivated wheat area and contributes about 10% to the total global wheat production. Durum wheat in Iran is grown on 300-400 thousand hectares with an average annual production of 500-600 thousand tons. Similar to other crops, insufficient yield stability in durum wheat is recognized as a one of the factors responsible for the gap between actual yield and potential yield. In breeding programs, the identification of superior genotypes is difficult due to environmental variability of target locations and the interaction of these variabilities with the investigated genotypes. Therefore, it is important to evaluate the advanced agronomic lines across various environments and over multiple years to ensure their yield stability and production (Yan & Rajcan, 2002). Many statistical models have been suggested to analyze genotype (G)× environment (E) interaction. GGE (genotype plus genotype-by-environment) biplot method is a multivariate model, which is based on principal component analysis that simultaneously represents G, E and G×E interaction on a graph known as biplot. GGE biplot is widely used in agricultural research as it provides a simple graphical interpretation of G×E interaction. The aim of the study was to evaluate the grain yield stability and adaptability in some promising durum wheat lines grown in moderate regions of Iran.

Eighteen promising durum wheat lines (G1-G18) along with two control cultivars (durum wheat cv. Hana and bread wheat cv. Parsi), were investigated based on a randomized complete block with three replications for two cropping seasons (2016-2017 and 2017-2018) at four Agricultural Research Stations (including Karaj, Ahwaz, Kermanshah, Neishabour and Isfahan cities, Iran). Combined analysis of variance for grain yield was performed using ADEL-R software. The GGE biplot methodology was employed to analyze G×E interaction (Yan, 2001). The GGE biplot model was used for the following purposes; (i) evaluation of yield stability, (ii) the simultaneous selection for yield and stability, (iii) identification of ideal durum wheat genotypes, and (iv) assessment of the characteristics of and relationships among the testing environments.

About 70% of variation was related to environment, 1.7% to genotype and 13.5% to genotype× environment interaction. Overall the grain yield of the lines ranged from 6.57 to 7.26 t.ha-1 and the G20 and G2 lines had the lowest and highest grain yield, respectively. Also, G6 and G16 lines had higher yield than Dena cultivar (G1). Surveying Polygon of GGE biplot showed that genotypes G2, G16, G5, G4, G20, G8 and G6 which had the most distance from Bipolt center and located in Polygon vertices that they were premier genotypes. The lines which designed from Biplot center divided the shape of Polygon to four environments. The first environment was included into the Isfahan in which genotype G6 had the most performance. The second environment was included into the Karaj that G2 was premier genotypes of this environment. The third environment was included into Kermanshah that genotype G16 was high performance genotype in this environment. The fourth environment was included into the Neishabour in which genotype G20 was premier genotype. The G12, G3, and G10 genotypes, which were located near the center of the biplot, had performance in all environments. Simultaneous evaluation of grain yield and stability through environment coordinate (AEC) biplot showed that genotypes G2, G1 and G18 with the higher grain yield were the most stable genotypes. There were many similarities between Karaj and Kermanshah environments as well as Karaj and Isfahan. The angles between these two environmental groups were less than 90 degrees. In contrast, the angle between Neishabour environment and Kermanshah and Karaj environments was distorted and near 180 degrees. These results verified the Karaj station was close to the ideal environment. G2 and G16 genotypes were identified as favorable genotypes in Karaj environment.

GGE Biplot was an appropriate graphical method for simultaneous selection of performance and stability of cultivars and lines. Based on the results, genotype G6 in Karaj, G6 in Isfahan and G20 in Neishabour were the best genotypes in terms of yield and stability. Generally, G18 can be considered as a favorite promising line compared to the control cultivar Hana and as a candidate in the temperate climates.