زین العابدین طهماسبی سروستانی

Energy is a limiting factor for agricultural sustainability due to costs and supply security. Agriculture section as one of the world's major food suppliers, has faced challenges in recent times due to increased energy consumption trends. This rise in energy consumption has led to increased production costs, negative impacts on food security, and environmental concerns. Therefore, achieving a balance between energy demand and supply in agricultural systems and assessing their economic performance is essential. With the recognition that soybean [Glycine max (L.) Merril] plays a crucial role in ensuring food security; a study was conducted in 2019 to analyze the energy flow and economic costs of soybean production at the provincial level in Mazandaran, Iran.

To assess the economic efficiency and energy consumption pattern in soybean farms, data were collected through direct interviews with 301 soybean farmers. The inputs used for estimating energy efficiency per hectare of soybean cultivation included fossil fuels, machinery, human labor, seeds, irrigation water, electricity, fertilizers, and chemical pesticides. The produced soybean grain was also considered as an output energy source. Life Cycle Cost (LCC) methodology was employed to evaluate the economic efficiency of soybean production; for this purpose, the farm gate was defined as the system boundary, and one hectare of soybean farm was taken as the base unit for all analyses. The social costs of emissions, in addition to the fixed and variable production costs that are addressed in most studies, were evaluated and analyzed. In the current study, the social costs of pollutant emissions in soybean production agroecosystems were considered from two aspects: (1) emissions on the farm and (2) pollutants generated from electricity generation. These costs were estimated using the standard coefficients established in previous researches.

Based on the results, diesel fuel, nitrogen chemical fertilizers, and consumed seeds had the highest shares of total input energy in soybean production with 47.90%, 19.61%, and 13.53% respectively. The average energy productivity for soybean production in Mazandaran province was calculated to be 0.16 kg MJ-1. From this point of view, Galugah county was the best with 0.25 kg MJ-1, while Amol was the worst with 0.11 kg MJ-1 compared to other scrutinized counties. In terms of the type of consumed energy, the results indicated that the current soybean production in Mazandaran province is not sustainable due to heavy reliance on non-renewable energy resources such as diesel fuel and nitrogen chemical fertilizers. The LCC of soybean production in Mazandaran province, including variable, fixed, and social costs resulting from emissions, was estimated to be an average of $327.90 per hectare. Among these costs, variable costs accounted for the highest share in soybean production in the region with $299.52 per hectare (approximately 91%).The average wage paid to owners of agricultural machinery and equipment was $141.85 per hectare (equivalent to 47.36%), and the average wage for human labor was $85.77 per hectare (equivalent to 28.64%). These two factors were the first and second most significant contributors to production costs for the soybean crop, respectively. Together, they accounted for approximately 69% of the total production cost (LCC). Carbon dioxide emissions, accounting for 41.16% (mainly due to diesel fuel combustion and urea fertilizer consumption on the farm), constituted a significant portion of the social cost resulting from emissions (at $7.38 per ton).

In general, the results of the survey of 301 farms indicated that soybean production in Mazandaran province, with an average energy efficiency of 2.43, is economically justifiable in terms of energy balance and constitutes a profitable agricultural product in the region, with a profit-to-cost ratio of 1.86.

Obtaining a high dry matter yield is one of the most important goals of plant physiologists. In this regard, it is necessary to know the effective traits in the production of plant dry matter. Salinity stress is also one of the most important non-biological stresses that limits plant growth and affects the morphological, physiological and biochemical properties of plants. Therefore, in order to understand the relationship between dry matter yield and antioxidant properties, photosynthetic and non-photosynthetic pigments of mint under salinity stress, an experiment was conducted as a factorial split-plot (18 mint ecotypes, including longifolia, pulegium, spicata, rotundifolia, mozafariani and piperita, salinity stress at control, 2.5, 5 and 7.5 dS/m levels and harvest stage at   2 stages), based on a randomized complete block design with four replications. The results showed that salinity stress affected the correlation between dry matter and other studied traits. Also, path analysis at different levels of salinity stress showed that total chlorophyll traits had a very high direct effect on dry matter yield. On the other hand, at a 7.5 dS/m salinity level, the dry matter yield of the plant depended on a greater number of traits compared to lower-salinity stress levels. Also, the correlation between traits in the first and second harvest stages was different. The anthocyanin pigment trait had a positive and significant correlation with dry matter yield at 7.5 dS/m. The indirect role of carotenoid pigment was also evident in severe stress. Based on path analysis, all the studied traits, including non-enzymatic antioxidants and anthocyanin and carotenoid pigments, were strongly dependent on the total chlorophyll trait to affect the dry matter yield.

Closing the gap between actual yields which are currently obtained from the fields (actual field yields) and the maximum yields that can be achieved under favorable management conditions (attainable yield) is one of the most critical problems in crop production in Iran and the world. Quantifying the yield gap and identifying its primary causes for this purpose can be a key and promising strategy to increase production per unit area and to achieve food security. Meanwhile, considering the importance of oilseeds like soybean [Glycine max (L.) Merril] in the global economy and the need for edible oils and vegetable proteins, estimating and identifying the causes of the yield gap, while increasing production, it can improve land use and labor efficiency, and leads to costs saving and sustainable production. In this way, a survey study was conducted in 2019 to identify and determine the share of each of the managerial factors affecting the soybean yield gap in 301 farms in Mazandaran province.

In the present survey, CPA method was used to investigate the decision-making factors which limit soybean yield and to estimate its yield gap in 13 soybean cultivated cities of Mazandaran province. For this purpose, all information relevant to crop management, from seedbed preparation to harvesting, was gathered through interviews with 301 soybean producers. These management factors included items such as use or non-use of a plow, number of secondary tillage, planting method, field area, previous crop, the used cultivar, seed rate and its preparation site, inoculation/non-inoculation of seeds with N-fixing bacteria, type and the amount of fertilizers, type, amount, and number of herbicides, fungicides, and insecticides usages, number of irrigations and the amount of used water, irrigation type and harvesting methods. Field monitoring data included 81 quantitative and qualitative crop management variables that the relationship between all these variables and actual field yields was analyzed using stepwise regression in SAS (v9.1) software. In the end, the contribution of each limiting factor to the creation of a yield gap was determined using the resulting production function and management parameters values.

The findings of this study revealed that of the 81 studied management variables, the final production function with 10 independent variables was selected. These variables included the sari variety (J.K-695), previous crop (faba bean), use the row planter, number of secondary tillage, sulfur rate, application of herbicide, KCl, and (NH4)2HPO4 fertilizers, sprinkler irrigation system, and surface irrigation, which were identified as the main limiting factors for soybean yield in Mazandaran province. Based on the difference between the average actual yield recorded on farms (2464.97 kg ha-1) and the maximum attainable yield (6028.66 kg ha-1) predicted by the production function, the yield gap was 3563.70 kg ha-1, which is three factors including sulfur rate, previous crop (faba bean) and sprinkler irrigation system with the values of 873.87, 620.49 and 546.33 kg ha-1, respectively, had the highest share (24.52, 17.41 and 15.33%, respectively) in of the soybean yield gap.

According to the predicted attainable yield which derived from actual farm data it seems that adoption of proper crop managements such as using sulfur fertilizer resources appropriate to plant needs, an appropriate crop rotation and selection of plants suitable for rotation, providing facilities and modernization of agricultural machinery, and develop and promote new irrigation can reduce this gap (59%) and significantly improve soybean yield in Mazandaran province.

Food security and sustainable agriculture are among the most challenging issues for the human being in the present age. These daunting challenges have arisen in the face of dramatic population growth as well as rising living standards, lifestyle, and, as a result, increased demand for a variety of foods. Due to limited water resources and arable lands, to achieve more production, it is necessary to increase the yield per unit area by using more materials (e.g., chemical fertilizers, pesticides, and fossil fuels) and energy. Obviously, in addition to the higher cost, it will lead to irreparable environmental consequences. In this regard, to achieve more sustainable production of agricultural products, there is a need to carefully evaluate the environmental status of these products in order to identify environmental hotspots to optimize them. Due to this, a study was conducted to assess the environmental damages to the soybean production system in different cities of Mazandaran province with a life cycle assessment (LCA) perspective. 

In the present survey, LCA approach was applied to evaluate the environmental impact and determine the most important hotspots of soybean produced in the cities scale of Mazandaran province (13 cities with soybean cultivation). LCA is a method that examines the environmental impacts associated with a product (or process) throughout its lifetime by accounting for resource consumption and pollutant emissions. For this purpose, the farm gate was considered the system boundary. Necessary data for LCA inventory were also obtained through face-to-face interviews with 303 farmers in 2019 and the EcoInvent 3.5 database in SimaPro 9.0.0.49 software. The potential environmental impacts were assessed by the IMPACT2002+ (v2.15) model in the software based on 1 ton of soybean seed produced as the functional unit (FU). Finally, impact assessment results of the soybean production system were presented in four environmental damage groups: human health, ecosystem quality, climate change, and resources. 

The findings revealed that soybean cultivation in the region and under the current conditions of inputs consumption has the highest impact on human health indicators that direct emissions from diesel fuel combustion and application of chemical fertilizers in the field play a major role in this damage category. Direct emissions from field operations claimed the highest share (>51%) in increasing global warming potential, which was mainly a result of CO2 emissions from burning diesel fuel. In addition, the findings of the present study showed that diesel fuel, followed by nitrogen fertilizer, had the most substantial role in the resources damage category. More generally, the total environmental damage for the production of 1 ton of soybean seed in surveyed cities ranged from 228.76 to 439.77 mPt, among which the cities of Galugah and Qaemshahr (228.76 and 261.18 mPt, respectively) had the least and Amol, and Sari (438.06 and 439.77 mPt, respectively) had the most value. To sum up, the LCA approach has been able to quantify the contribution of the soybean production system in causing environmental damage in the form of different damage categories by considering the amount of each of the inputs and their emissions based on a specific FU. 

In general, it can be concluded that diesel and chemical fertilizers inputs and direct emissions caused by their consumption on farms were the most substantial environmental hotspots. These factors, in turn, arise from the mismanagement of soybean farms in Mazandaran. Hence, it seems that efficient management practices by informing farmers and support of the authorities to provide appropriate facilities to farmers can be an important step toward reducing the environmental consequences and developing the cultivation of this valuable crop in the region. 

Acknowledgments

The authors would like to acknowledge the financial support of Tarbiat Modares University and the assistance of the esteemed officials of Sari Agricultural Sciences and Natural Resources University, Agriculture-Jihad Organization of Mazandaran province, and especially the honorable farmers of this province to collect data for this study.

Mungbean (Vigna Radiata L. Wilczek) is considered as one of the important tropical and semi-tropical pulses. This plant is important in terms of nutritional value, hay supply, green fertilizer and improvement of soil fertility (Al-Shaheen et al., 2016). According to the previous studies, water deficit causes morphological, physiological and biochemical changes within the plants, thereby negatively affecting their growth and yield. Various studies also suggest that water stress restricts nutrients absorbed by the plant as the absorption of nutritional elements and the water available for the plant roots are closely dependent on each other (Aghdasi et al., 2018). Therefore, spraying liquid fertilizer can be offered as an appropriate method of feeding the plant in this condition (Alipour & Zahedi, 2017). In this regard, the choice of the landraces and suitable cultivars and nutrition and irrigation management can play an important role in increasing quantity and quality of pulses and reduce negative effects of various environmental stresses. The present research aimed to study the effect of water deficit stress on some quantitative and qualitative traits of mungbean Parto variety under the foliar application and non-application of nano iron and manganese chelates.

In other to determine the effect of water deficit stress and nano Fe and Mn chelates foliar application on yield of mungbean cultivar Parto in 2013-14, an experiment was carried out in the agricultural research farm station of Tarbiat Modares university, Tehran as a split plot in a completely randomized block design with three replications. The experimental treatments in the main plots were three levels of irrigation regime [no cessation of irrigation (S1), cessation of irrigation at reproductive stage whenever 70 % of the field capacity (FC) was depleted (S2), cessation of irrigation at vegetative stage whenever 70 % of FC was depleted (S3)]; and in the subplots were 10 levels of foliar application [no foliar application of the nano fertilizers as control (F1), foliar application of pure water (F2) including 1/1000 chelated nano iron (F3), 3/1000 chelated nano iron (F4), 1.5/1000 chelated nano manganese (F5), 3/1000 chelated nano manganese (F6), 1/1000 nano chelated iron+ 1.5/1000 nano chelated manganese (F7), 1/1000 nano chelated iron + 3/1000 nano chelated manganese (F8), 1.5/1000 nano chelated manganese + 3/1000 nano chelated iron (F9), 3/1000 nano chelated iron+ 3/1000 nano chelated manganese (F10] at withholding irrigation periods.

The results showed that the water deficit stress and the foliar application of iron and manganese nano-chelates significantly affected the most of the plant traits at 1% probability level. Among water deficit stress levels, the termination of irrigation at the reproductive stage resulted in the lowest yield and yield components, whereas the highest values for yield performance yields were obtained from control (optimum irrigation). The results showed that the highest values for the plant yield and yield components were achieved with different levels of foliar spraying of iron and manganese nano-chelates at the vegetative and reproductive stage, especially at the vegetative growth stage, while control (no spray) decreased the yield and yield components in the plant. Also, the interaction between the two main treatments were significant for the most of the traits at 1% probability level. The results showed that the quantum yield of PSII, due to increased the F0 and decrease in Fm and Fv, in mungbean grown under water-deficit conditions in reproductive (60.2) and vegetative (97.4) stages declined significantly in comparison to the control group.

The means comparison for the interactive effects of foliar spraying and water deficit stress suggested that the greatest grain yield was related to the treatment of optimum irrigation and simultaneous spraying pf one per a thousand nano chelated iron and three per a thousand nano chelated manganese (1765/3 Kg/ha) and the lowest yield was associated with the treatment of the water stress at the reproductive stage and no spraying (376/0 Kg/ha). The was found to be a high correlation between biological yield and other morphological traits, especially dry weight of the leaf (r=0/90**). Thus, it is suggested that these elements can be utilized as a factor for decreasing stress and also increasing productivity in the plants.

Drought is a common problem that seriously affects the quantity and quality of agricultural produce. More than 50% of the world's regions are located in dry and semi-arid regions. Plant growth decreases in drought stress. Water shortages in the world and in Iran have always been a limiting factor for plant cultivation. Drought is a common problem that seriously affects the quantity and quality of agricultural products, such as medicinal plants. The use of agronomic techniques, including soil biological conditions (using mycorrhiza and Azospirilum) and the use of chemical fertilizers, may be effective in reducing the effects of drought stress.

In this regard, a field experiment was carried out in two regions of Tehran (semi-arid) and Varamin (arid) in the period of 2014-15. The experiment was split factorial in a completely randomized block design with three replications. The main factor consisted of three treatments without water stress, moderate stress and severe stress (irrigation at 50, 40 and 30 percent of field capacity), and the factorial arrangement consisted of three fertilizer regimes (no fertilizer application, 50 and 100 percent Nitrogen + Phosphorus application requirements for plant), mycorrhizal fungi and Azospirilum bacterium (application and non-application) were considered as a subplot. Drought stress treatments at flowering stage (during flowering until the end of the season) were applied based on soil crop capacity. The following steps were applied to apply water deficit treatments, respectively: First, the field capacity was obtained, first, a plot (length of two meters × two meters wide) from each experimental site completely up to the end of the plain wall of the water filled and was enclosed with plastic (to prevent water evaporation and error) to the soil completely saturated with water. After 48 hours, the water was removed by gravity from the coarse porosity, the plastic was removed from the plots, the soil sample was prepared and, after weighing, in an oven at 105° C for 24 clock was placed. The sample was then calibrated with a precision weighing scale and evaporated moisture content (soil moisture content).

The results showed that grain yield and its components (biological yield, 1000 seed weight, number of seeds per plant, number of capsules per plant and number of lateral branches per plant) with irrigation reduction (moderate and severe), were significantly dry weather in the Varamin area decreased. Inoculation of mycorrhiza with combined application of chemical fertilizers and Azospirillum improved seed yield, biological yield, 1000 seed weight, seed number per plant, number of capsules per plant and number of lateral branches per plant under drought stress conditions in arid and semiarid regions. Biological and grain yield in terms of absence of drought stress along with application of chemical and biological fertilizers to the conditions of severe drought stress, with non-application of chemical and biological fertilizers were 60% and 65% respectively for Tehran region and 50% and 59% for Varamin area increased. Reducing the amount of photosynthesis, reducing carbon dioxide absorption, increasing transpiration and decreasing water absorption, increasing leaf temperature due to reduced transpiration and reduced absorption of food can be mentioned due to reduced biological yield and grain yield under drought stress.

In general, drought stress has reduced the yield and the use of biological fertilizers has caused the plant's resistance to drought stress.

To improve crops productivity under drought stress conditions, not only proper management of inputs in time, amount and form, but also the understanding of important physiological processes and defense mechanisms are required to avoid drought stress. Most plant species have the ability to form a symbiosis relationship with the Arbuscular mycorrhizal fungi. AMF could increase growth and yield of plants under water stress, and it is one of the most important biological fertilizers which can be used in mycorrhizal and Azospirillum fields. Research results have shown that mycorrhizal and Azospirillum fungi can moderate the adverse effects of drought stress in plants. One of the most important effects in terms of drought stress is changing the levels of some hormones in plant such as acetic acid and indole acetic acid. Other effects are direct absorption of water by fungal hyphae in soil and its transfer to the host plant, increasing leaf gas exchange, photosynthesis rate as well as enhance the activity of antioxidant enzymes in corn, excellent nitrate and phosphorus assimilation. In addition, extend the water absorption by increasing the leaf water hydration, leaf photosynthesis activity, osmotic regulation and changes in cell membrane flexibility. Hence, the current study was aimed to evaluate chemical fertilizers (nitrogen + phosphorus) and biological fertilizers (Azospirillum and mycorrhizal fungi) effects on water deficit stress on morpho-physiological traits and yield of evening primrose at different experimental stations (Tehran and Varamin regions).

Two experiments were conducted at two experimental stations in Tehran and Varamin in 2014 and 2015. Experiments were conducted in a split factorial layout within a randomized complete block design with three replications. Three irrigation regime treatments (IR 50 % FC, IR 40 % FC and IR 30 % FC; 50, 40 and 30 percent of field capacity) were randomized to the main plots. Subplots were consisted of factorial combinations of three chemical fertilizers (CF 0, CF 50 % and CF 100 %: no-application, 50 and 100 percent of nitrogen + phosphorus needed by plant) as well as four biological fertilizers (“-M and –Az” and “+M and +Az”: non-inoculated and inoculated with mycorrhizal and Azospirillum).

Water stress (moderate and severe) reduced plant height, shoot dry weight, leaf area index, seed yield, phosphorus content and relative water content. However, the highest water use efficiency was obtained at moderate water deficit stress. In addition, the highest root dry weight, root ratio shoot dry weight and catalase were obtained at severe water deficit stress. The application of chemical fertilizers and biological fertilizers in all cases mitigated the negative effects of water deficit stress on plant height, shoot dry weight, root dry weight, root ratio shoot dry weight, leaf area index, seed yield, phosphorus content, catalase, relative water content and water use efficiency traits. Water use efficiency of evening primrose increased with moderate water deficit, application of chemical (Nitrogen + Phosphorus) and biological (mycorrhizal fungi and Azospirillum) fertilizers.

 The compelling results of this study revealed that the inoculation mycorrhizal and Azospirillum could improve evening primrose growth under water deficit stress. Results showed that the application of biological fertilizers can improve evening primrose growth under drought stress. Moreover, mycorrhiza symbioses can increase absorption of moisture and nutrients, reduced irrigation requirements, enhancement drought resistance, more access to food in new places, production of thinner roots, increase root length and nitrogen fixation, which lead to reduction of drought detrimental effects.

Leaf area is a key indicator for the growth and production of plant products and also determines the efficiency of light consumption. Therefore, the study of diversity and also the estimation of leaf area in different mint ecotypes is particular importance. One of the common methods for estimating leaf area is regression analysis, the leaf area as independent variable, and leaf length and width as dependent variable. In this study, leaf area of ​​18 mint ecotypes with different models of ANFIS, artificial neural network (MLP and RBF), linear and nonlinear regressions using two inputs of leaf length and width in four levels of salinity stress (control, 2.5, 5 and 7.5 dS/m) were estimated in two levels of harvesting. The results showed that there is a high correlation between length and width with leaf area, so that the width correlation with leaf area was greater than leaf length. Among the regression models in both harvest levels and at all levels of salinity stress, the NLR model is presented as the best and most accurate model. ANFIS model was harvested in both stages and at all levels of stress was more accurate than other models and less error rate was obtained. Also, the results of cluster analysis showed that there is a good variation between ecotypes. In addition, the mean comparison between different cluster analysis groups showed that the highest amount of length, width and leaf area was taken in both stages and at all levels of salinity stress was related to E18.

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 oil seeds cultivars to environmental variables is one of the principal of agriculture planning to achieve maximum qualitative and quantitative yield. Water deficit stress and sufficient nutrition are the most important factors limiting yield production by changing the physiological processes of the plant. Iran is considered as the arid and semi-arid with average rainfall of 250 mm. On the other hand, 33% of agriculture land is devoted to dry cultivation. Water deficit by affecting on vegetative and reproductive growth period and balance between them will change yield and product quality.

In order to study the responses of three winter canola cultivars to late season drought stress and foliar application of Mn and Zinc sulfate fertilizer on physiological, morphology characteristics and yield, a split factorial experiment was carried out based on randomized complete block design with three replications in 2017-2018 at the Karaj province. Irrigation in two levels, normal and water holding at flowering stage to next, foliar application in four levels, sprayed with water (control), foliar application with zinc sulfate, foliar application with Mn sulfate, foliar application composition with zinc sulfate and Mn sulfate (each of them was with concentration of four per thousand) both in main plot and three cultivars included Nima (control) and two new lines KS7 and R15 in sob plot. Foliar application was applied during the stem elongation stage. When the 50% of pod appeared total chlorophyll and leaves carbohydrate solution content was measured as index of drought stress damage. Eight traits were measured on 10 random plants per plot. The traits were plant height, number of pods /plant, number of seeds/pod, 1000 seed weight, seed yield, biomass yield, oil percentage and oil yield.

The results showed all characteristics significantly were influenced by water holding and foliar application. Interaction of water holding and foliar application was significant in attributes of plant height and oil content. Main effect of cultivar and interaction of water holding and cultivar were significant in all treatment except oil content. Due to water holding increasing in soluble carbohydrates and reducing the concentration of chlorophyll was occurred. The yield components of canola because of irrigation disruption decreased which leads to lower grain and rapeseed oil yield. The results showed that in normal irrigation, the highest seed yield (5168 kg.ha-1) oil yield (2244 kg.ha-1) and water use efficiency (0.99 %) were related to R15 line but in water holding condition the Nima cultivar obtained the highest achievements. In complete irrigation, foliar application of the two micro elements increased the traits studied. Most of the seed oil yield (1728 kg.ha-1), the weight of one thousand seeds (3.21 g), biological yield (15675 kg.ha-1) and water use efficiency were related to the main effect of zinc sulfate and Mn sulfate combination. Spraying plants with zinc sulfate and Mn sulfate improved plant height and increased oil content in drought stress condition in relation to spray by water (control). Among cultivars, Nima cv. had better outperformed relative to KS7 and R15 in normal irrigation. In water holding treatment, two cultivars R15 and Nima narrowly to each other had better outperformed relative to KS7. Non significant interaction effects of foliar application and cultivars for seed and oil yield indicated that all cultivars had similar trend. Drought not only causes dramatic loss of pigments but also leads to disorganization of thylakoid membrane, therefore reduction in chlorophyll contents is expected. The water holding condition in late season may influence plant growth that can be attributed to the lose yield components.

Correlation between drought situation and yield components in all cultivars, identify the most suitable indicators for monitoring drought tolerance cultivars. According to these results, R15 can be recommended for semiarid regions due to maximum seed and oil yield among and non stress condition. In water deficit condition R15 can be recommended for semiarid regions due to maximum seed and oil yield among and non stress condition.

To study the response of sesame plant under water deficit condition to the management methods, a factorial split experiment using a randomized complete block design with three replications was conducted at the Jiroft Agricultural and Natural Resources Research and Education Center in 2015. Irrigation treatments were soil field capacity, permanent wilting point, root development depth and percent availability water to sesame (with four levels: 100, 80, 60 and 40% of the required water). Ecotypes used, were Halil, Borazjan 2 and local population of Jiraft. In this experiment, wheat straw mulch used with two levels: (without using mulch and using 7.5 tons of mulch per hectare). The results showed that simple effects of drought stress and mulch and the interaction of drought stress × mulch on all measured traits were significant at the probability level of 1%. The interaction of drought stress × ecotypes × mulch was significant only for number of branches and oil percentage. The highest and lowest seed yield and oil percentage were belonged to Haleil and Borazjan 2 ecotypes, respectively. Use of 7.5 tons straw mulch per hectare resulted in improving the means of measured traits as compared to that of control. The highest percentage of oil was obtained from Halil ecotype by using straw mulch and irrigation level of 100% (53.10%), but its difference with irrigation level of 80% (52.9%) was not significant. In general, the results showed that the using of straw mulch of wheat reduced positively the effects of water deficits.

In order to study the effects of water deficit stress on reduction of quality traits of Vigna Radiata (Parto variety) under iron and manganese nano-chelate foliar application, an experiment was conducted as split - plot management in randomized complete block design with three replications during 2013-2014 in the Research Farm of Agricultural College, Tarbiat Modares University. Experimental treatments in main plots were three levels of Irrigation regime and in subplots were 10 levels of foliar application at withholding irrigation stage. The results showed that water deficit and iron and manganese nano-chelate foliar application were significant for the most of plant traits at 1% probability level. Water deficit stress reduced all of the studied traits except carotenoid pigment content and proline. Also chlorophyll content and carotenoid were increased by foliar application of iron and manganese nano-chelate at both vegetative and reproductive stages. Finally, interaction between two main treatments were significant for the most of the traits at 1% probability level.

Chitosan is a glucosamine polysaccharide deacetylated form of chitin species and could be used as biotic elicitor to improve secondary metabolites and as a fertilizer it controls the release of chemical compounds of toxins and stimulates germination and plant growth. Thus, to evaluate the effect of chitosan NPs on barley plants under late season drought stress, a factorial pot experiment was performed based on a randomized complete block design with three replications. The experimental factors were NPs concentrations at 4 levels (0, 30, 60 and 90 ppm), method of usage at 2 levels (foliar and soil application) and irrigation regimes at 2 levels (normal irrigation and with-holding irrigation 15 days after pollination). Experimental procedure consisted of planting seeds, preparing chitosan NPs solution, and using solutions through soil and foliar application at three plant growth stages (tillering, stem elongation and heading). Results indicated that drought stress significantly decreased contents of carotenoid, chlorophyll a, the chlorophyll b, the total chlorophyll, rate of photosynthesis, stomatal conductance, transpiration, grain yield, as well as, biomass. Results also showed that contents of soluble carbohydrate, glucose, sucrose, fructose, intercellular CO2 concentration (Ci) and photosynthetic water use efficiency (WUE) were increased. Also, under both irrigation regimes, application of chitosan NPs significantly increased the chlorophyll a, the chlorophyll b, the soluble chlorophyll and the glucose. Application of 60 and 90 ppm NPs significantly increased grain yield as compared to that of control. Signifficant diffrences for some traits under study between two usage methods of NPs were not observed. In general, application of chitosan NPs reduced negative effects of drought stress for barley plants and improved its growth and seed yield.

Aloe barbadensis Miller. is one of the most economically important medicinal plants in many countries of the world. This investigation aimed at evaluating the effects of water stress and zeolite on growth, yield and chemical compositions of A. barbadensis. The study was conducted in the research greenhouse of Faculty of Agriculture, Tarbiat Modares University. The plants were harvested 90, 180 and 270 days after imposing the treatments. Water deficit stress decreased growth, leaf fresh and gel fresh weight and increased biochemical compounds. The results showed that the greatest number of new leaves and pup were produced by the plants irrigated 20% and 40% FC with 8 g zeolite, respectively. Generally, the highest leaf fresh and gel fresh weight were observed 270 days after imposing the treatments when plants were irrigated after depleting 40% of the FC and amendment with 8 g zeolite (624.13 and 397.17 g), respectively. The water use efficiency increased with less water and more zeolite availability. The highest water use efficiency of leaf and gel was obtained from the plants irrigated after depleting 60% of field capacity and treated with 8 g zeolite. In addition, the results indicated that the maximum aloin concentration (23.48%) and proline accumulation (0.85 (mg [g FW]-1) were obtained 90 days after imposing the treatments when the plants were irrigated after depleting 80% and 60% of FC where no zeolite was applied, respectively. Irrigation after 80% depletion of FC without zeolite application resulted in the highest fructose and glucose content, respectively (234.71 and 79.83 mg g DW−1). In general, application of zeolite could alleviate water stress adverse effects, and improved plant growth and yield. Severe water stress decreased leaf yield and plant growth, while caused an increase in biochemical compounds.

In order to assess the effect of drought stress on seed chemical compositions and determine a stage In order to assess the effect of drought stress on seed chemical compositions and determine a stage that drought stress has the most effect on seed compositions, an experiment was conducted as a split factorial based on complete randomized block design in three replications in agriculture faculty of Tarbiat Modares University in 2014. Four treatments of drought stress were exerted as withholding irrigation at flowering stage, pod formation, seed filling stage, and control (without stress). The other treatments were two soybean cultivars (Williams and L17) and the seeds resulted from three planting dates in Moghan in a last year (10 May, 10 June and 10 July). The measured traits included fatty acids percent, oil and protein percent of soybean grain. The results indicated that effect of drought stress was significant on oil and protein percent and also fatty acids except palmitic acid. The lowest percent of oil (19.29% ) and the highest percent of protein (37.36 %) were obtained by drought stress at seed filling stage. The highest percent of oleic acid (25.75%) and the lowest linolenic acid (5.98%) was observed in Williams at drought stress at seed filling stage. Regarding that the main purpose of soybean planting in Iran is oil production and drought stress at seed filling stage has negative effect on oil content, so irrigation in this stage of reproductive growth is necessary to achieve desirable oil yield.

Aloe vera is one of the most economically important medicinal plants in many countries which used in food, cosmetics and pharmaceutical industries; it is widely cultivated throughout the arid and semi-arid regions. Therefore, the current study was aimed to evaluate the effects of different water stress on growth, yield and aloin concentration during plant growth stages.
This study was conducted in research greenhouse of Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. The experimental design was a randomized complete block design with a split plot in time arrangement of treatments in four replicates. Treatments including water deficit stress (irrigation after depleting of 20%, 40%, 60% and 80% field capacity (FC)) and harvesting dates ( 90, 180 and 270 days after imposing the irrigation treatments). Irrigation treatments and harvesting dates were considered as main- and sub-plots, respectively. Growth changes, yield and aloin concentration were evaluated during growing period.
The results demonstrated that the growth and yield values decreased with increasing water stress severity. Generally, the highest number, width and thickness of leaf were observed when the plants were irrigated at 20% FC, which was higher increased by 19, 22 and 16%, respectively compared with irrigation after depleting 80% of the field capacity, respectively. Irrigation at 40% FC increased plant height and leaf length by 16% and 21%, respectively, compared with the irrigation at 80% FC. The highest leaf and gel fresh weight were observed in 270 days after imposing the irrigation at 40% FC which increased by 44 and 49% compared with irrigation at 80% FC. Results also showed that the pup number decreased with increasing water stress, the maximum pup number was observed when plants were irrigated at 40% FC at 90 days after imposing the irrigation treatments. aloin concentration and Total Soluble Solids (TSS) increased in Aloe vera plants under severe water stress. The highest aloin and TSS content was observed when the plants were irrigated at 80% FC at 90 and 270 days after imposing the irrigation treatments, respectively.
In general, severe water stress decreased leaf yield and plant growth while caused a significant increase in aloin concentration and TSS. Finally, irrigation after depleting of 40% of soil water content was the best treatment for growth and yield, also depleting of 80% of soil water content was the best treatment for aloin and TSS during all growth period.

In order to assess the performance of two soybean cultivars produced in two regions including Karaj and Moghan to drought stress at reproductive stages and also the impact of drought stress on yield and its components, oil and protein percent, an experiment was conducted as a split factorial based on complete randomized block design in three replications in agriculture faculty of Tarbiat Modares University during 2014. Four treatments of drought stress were exerted as complete withholding irrigation at flowering stage (R1-R3), pod formation (R3-R5), seed filling stage (R5-R7) and control (no withholding of irrigation) which were placed in main plot and other treatments were two soybean cultivars (‘Williams’ and ‘L17’) and two seed production sources (Karaj and Moghan) that were placed in sub plots. The results indicated that the effect of drought stress on pod number, 1000-seeds weight, seed yield and also oil and protein percent was significant. The highest seed yield (262.73 gram per meter square) was observed in control (no stress) and the lowest yield (162.22 gram per meter square) belonged to drought stress at pod formation stage. Also the interactions of drought stress × cultivar and drought stress × seed source were significant on grain yield. The lowest seed oil percent (18.24 percent) and the highest protein percent (37.28 percent) of seeds were obtained at seed filling stage. With considering these results, the irrigation at pod formation stage (R3-R5) is necessary for preventing the reduction of soybean seed’s yield.

In order to determination of suitable cropping pattern for agricultural lands of Golestan province, were used geographical information system (GIS) and analytical hierarchy process (AHP).
At first, agroecological requirements of crops were identified from scientific resources then classified and required thematic maps were provided. The digital environmental layers overlaid and integrated in GIS media with AHP weights, then zoning of lands were done in 4 classes for any crops. In future step, the crops feasibility maps and land type and unit maps (as management unit) were overlaid then were identified the high suitable and suitable classes in each unit for crops cultivation and suitable cropping pattern was selected with respect to parameters such as plant water requirements, water resources status, the net benefit and the other economic and development factors. In introduced patterns for south lands of province, were suggested dry farming of high net benefits and autumn crops. In the most agricultural lands in southern and central of province were proposed crops such as wheat, canola, beans, chickpea, berseem clover in the patterns. The results showed that the north and northeastern lands of this province, has more adapted to cropping pattern of chickpea and barley due to environmental constraints. Also, cultivation of spring and summer crops is possible in high suitable areas, in the south and southwestern province as rainfed farming with supplementary irrigation.

To study some quantitative and qualitative traits of Cucurbita pepo L. under fertilizer and water deficit stress, a trial was conducted in the research field of Tarbiat Modares University in 2011 and 2012 cropping years. In this study, the experiment was performed in factorial randomized completely block design with three replications. and water deficit at three levels (normal irrigation, withholdingirrigation at milk stage, withholdingirrigation and spraying sodium chlorate at milk stage). Results showed that nitrogen fertilizer treatment significantly affected all traits studied except seed number and stress treatment had significant effects on all traits except seed number, seed length, and stearic acid content at 1% level of significance. In this study, increasing water stress reduced the content of all traits studied except linoleic acid content. In addition, increased levels of nitrogen fertilizer led to the decreased content of all traits studied. The highest values for fruit and seed weight, seed width, seed diameter, oil, linoleic, oleic, palmetic, and stearic acid were obtained at a nitrogen fertilizer level of 60kg.ha-1. Totally, nitrogen fertilizer (60kg.ha-1) and control irrigation treatments are recommended as the most suitable treatments to gain maximum seed yield.

To study the effects of two irrigation regimes and application of barley residue، zeolite and superabsorbent polymer on forage yield and some physiological traits of maize and sorghum، an experiment was conducted over two years in Kerman، Iran. A randomized complete block design arranged in a factorial split was used with three replications. Two irrigation regimes of normal irrigation and water deficit stress based on 70 mm and 140 mm cumulative pan evaporation، respectively and two plant species (maize and sorghum) as factorial combinations were compared in main plots. Five combination treatments of barley residue، zeolite، and superabsorbent polymer، (I) -10 t ha-1 zeolite plus 4. 5 t ha-1 residue (ZR)، (II) - 60 kg ha-1 superabsorbent plus 4. 5 t ha-1 residue (SR)، (III) - 5 t ha-1 zeolite plus 30 kg ha-1 superabsorbent plus 4. 5 t ha-1 residue (ZSR)، (IV) - 4. 5 t ha-1 residue (R)، and (V) – control (C)، were compared in subplots. In maize، forage yield، maximum quantum yield (Fv/Fm) and chlorophyll concentration and in sorghum forage yield and Fv/Fm decreased significantly under water deficit stress. Maize produced higher forage yield (62. 8 t ha-1) than sorghum (49. 3 t ha-1). The application of 10 t ha-1 zeolite plus 4. 5 t ha-1 residues (ZR) had the highest forage yield، and the control treatment had the lowest forage yield، soil water content and Fv/Fm. In most traits، there were no significant differences between the residue treatment (R) and the combination treatments of residue with the zeolite and super absorbent polymer. Maize planting associated with the application of 10 t ha-1 of zeolite plus 4. 5 t ha-1 residues is recommended in a double-cropping system in Kerman.

In order to assess the effects of organic and inorganic nitrogen sources on yield of some winter rapeseed (Brassica napus L.) varieties, soil physicochemical properties and available nutrient elements such as nitrogen, potassium, phosphorus, iron, manganese, zinc, copper and sulphur, two field experiments were carried out during 2008 - 2010 cropping seasons as factorial arrangement in randomized complete blocks design in three replications at the Agricultural and Natural Resources Research Center of Markazi Province, Arak, by using two factors of nitrogen sources at three levels of Azocompost, 50% Azocompost plus 50% urea, 100% urea and three rapeseed varieties including Okapi, Modena and Licord. Nitrogen sources were utilized such that a net quantity of 150 kg N/ha was added to the soil. The results showed that there were significant differences between the nitrogen sources for seed yield and soil properties including moisture weight, bulk density, soil electrical conductivity, pH, organic matter, saturation percentage, porosity percentage and infiltration velocity at 1% probability level. The rapeseed varieties had significant differences for seed yield and soil properties such as bulk density, electrical conductivity, organic matter, porosity percentage and also for the availability of nitrogen, potassium, iron, zinc, manganese and sulphur elements in the soil. In these experiments, the Licord variety showed a greater yield (3847 kg/ha) at integrated nutrition system compared to the other treatments. In addition, the availability of Fe, Mn, Zn and S in soil solution were increased, but the availability of K was decreased. In this research, the integrated application of Azocompost and Urea fertilizers, increased seed yield of Licord cultivar and improved the most of soil properties. Therefore, the integrated nutrition (50% Azocompost plus 50% urea) and extension of Licord variety cultivation area could be recommended for the rapeseed yield enhancement.

In order to compare the seed yield of 15 winter rapeseed (Brassics napus L.) genotypes, a field experiment were performed in 2006-7 and 2007-8 cropping seasons in Agricultural and Natural Resources Research Center of Markazi Province, Arak, Iran. Rapeseed genotypes were compared in a randomized complete block design with three replications. Means comparison showed that Licord (3795 kg ha-1), Modena (3655 kg ha-1) and Okapi (3277 kg ha-1) genotypes had the highest seed yield, respectively. In the second phase of this research, in order to evaluate the effects of sulphur (S) rates on seed yield and accumulation of macro nutrient in seeds of high yielding rapeseed genotypes, a field experiment carried out as factorial arrangement based on randomized complete block design with three replications, during 2008-9 and 2009-10 cropping seasons at the same site. Treatments were three rapeseed varieties (Okapi, Modena and Licord) and three rates of sulphur (0, 40 and 80 kg ha-1).The interaction effect between sulphur*variety was significant for seed yield and other measured traits. The combination of 40 kg ha-1 Sulphur*Okapi showed the highest seed yield and seed nitrogen content. Greatest seed phosphorus and potassium content was observed in Modena cultivar and S2 treatment (40 kg S ha-1). Licord cultivar showed the highest ratio of seed sulphur content at control and different rates of sulphur utilization in comparison with other vareties. In general, it is presumed that utilization of 40 kg S ha-1 can enhance seed yield and seed macro nutrient content, related to rapeseed genotype.

In this research, the spatial distribution of Fe, Cu, Zn and Mn on agricultural lands of Golestan province were evaluated using different interpolation methods such as, Kriging, Inverse Distance Weighted, Local Polynomial, Inverse Multiquadric and Radial Basis Function. Thus, 505 soil samples were provided from fields during 2008 and micronutrients rates were measured for each sample. The performance criteria for evaluation the used method were Mean Absolute Error (MAE), Mean Bias Error (MBE) and Root Mean Square Error with the Cross Validation method. The results showed that Inverse Multiquadric and Kriging (Exponential and Spherical models) were the best methods to estimate Fe and Mn. Kriging and Local Polynomial were also found as the most suitable and unsuitable methods for estimating Cu, respectively. Inverse Distance Weighted method with power one, had the highest precision (MAE=0.304 and MBE=0.002) for estimation of Zinc rate in this area. Semivariograms nalysis indicated that Mn and Cu were best fitted to a spherical model.

To study the effects of different irrigation regimes and the use of barley residue، zeolite and superabsorbent polymer on yield and water use efficiency of maize (SC 704) and sorghum (cv. Pegah) under minimum tillage، an experiment was conducted over two consecutive years (2012-2013) in Kerman، Iran. A randomized complete block design arranged in a factorial split was used with three replications. Irrigation regimes in two levels، normal (irrigation based on 70 mm evaporation from pan class A) and water deficit stress (irrigation based on 140 mm evaporation from pan class A) and plant species included two levels، maize and sorghum، as factorial combinations were compared in main plots. Combination treatments of zeolite، superabsorbent polymer and barley residue with 5 levels، were assigned to subplots that were as follows: I. 10 tha-1 zeolite plus 4. 5 t ha-1 barley residue (ZR)، II. 60 kgha-1 superabsorbent polymer plus 4. 5 tha-1 barley residue (SR)، III. 5 tha-1 zeolite plus 30 kgha-1 superabsorbent polymer plus 4. 5 tha-1 barley residue (ZSR)، IV. 4. 5 tha-1 barley residue (R)، V. Control (C). Based on the results، maize produced 62. 17 and 14. 03 tha-1 fresh and dry forage yield respectively، while the fresh and dry forage of sorghum were 47. 6 and 9. 29 tha-1 in the first cutting and 66. 62 and 13. 22 tha-1 in the sum of the two cuttings. In both plants water use efficiency and forage yield under water stress increased and decreased، respectively. Water use efficiency for fresh and dry forage yield of maize was 6. 31 and 1. 42 kgm-3 while this trait for fresh and dry forage yield of sorghum was 5. 06 and 1. 01 kgm-3 respectively. Application of 10 tha-1 zeolite plus 4. 5 tha-1 barley residue (ZR) with production of 66. 9 tha-1 fresh forage yield and 6. 8 kgm-3 water use efficiency in maize and production of 72. 07 tha-1 fresh forage yield and 5. 44 kgm-3 water use efficiency in sorghum had the highest values than any of the other treatments. Water stress increased the forage crude protein content but zeolite decreased it. For a double cropping system in the temperate zones of Jopar in Kerman، barley residue can be recommended after maize planting under minimum tillage together with application of 10 t ha-1 zeolite and 4. 5 t ha-1 barley residue.

Ecological studies can be used to identify the environmental potential in different regions to achievement maximum utilization. Geographic information system (GIS) and analytical hierarchy process (AHP) were applied to agro-ecological zoning of current agricultural lands in Golestan province for soybean cultivation. For this purpose, agro-ecological requirements of soybean firstly, identified according to scientific resources. Rating and thematic requirement maps were then provided. Studied environmental-components were: average, minimum and maximum temperatures, precipitation, slope percent, elevation, slope aspects, soil characteristics (OM, pH, EC, texture, nitrogen, phosphorus, potassium, calcium, iron, zinc), surface water and groundwater potentials. Each layer is classified into 4 classes according to Simple Limitation Method (SLM). The analytical hierarchy process (AHP) was used to determine the weight of criteria by using the questionnaires analysis sheet. The digital environmental layers overlaid and integration in GIS media then zoning of lands carried out in 4 classes (high suitable, suitable, less suitable and non-suitable). The results showed that 27.59% and 27.35% of this area were high suitable and suitable for soybean cropping, respectively. The less suitable and non-suitable regions were located in the north and northeast of Golestan province. In these areas, the limitation factors include high EC, low precipitation, deficient of some elements and low water resources. In this study, non-suitable class had the minimum area of Golestan agricultural lands (17.34%).