drought stress

Water scarcity in arid and semi-arid regions is a serious challenge for fodder production. Therefore, optimizing irrigation techniques and selecting drought-resistant cultivars, such as millet, is essential. This study investigated the effects of two irrigation methods, namely, regulated deficit irrigation and partial root-zone irrigation, at four irrigation levels (100%, 80%, 60%, and 40% of the plant's water requirement, WR) on forage yield, irrigation water use efficiency, forage protein percentage, and yield of hybrid pearl millet (Nutrifeed variety). The research was conducted using a split-block (strip-split-plot) design based on a randomized complete block design (RCBD) with three replications, utilizing the drip irrigation method with tape strips at the research farm of Shahid Bahonar University of Kerman, during the 2017 and 2018 growing seasons. The results demonstrated that the partial root-zone irrigation treatment, by supplying 100% WR resulted in the highest fresh and dry forage yields, with 80.20 and 16.27 t/ha, respectively. The 80% WR in the same method, in addition to being ranked second, with fresh and dry forage yields of 71.71 and 15.47 t ha-1, respectively, yielded the highest dry forage protein yield (1418.7 kg/ha) and water use efficiency based on fresh and dry forage yields (13.74 and 2.97 t/m3, respectively). Additionally, the highest protein percentage (11.41%) was observed in the partial root-zone irrigation treatment by supplying 60% WR. Overall, partial root-zone irrigation, by providing 80% WR, is recommended as a suitable strategy to improve irrigation water use efficiency and maintain the quality and quantity of forage under water-limited conditions.

Given that the majority of Iran's land area consists of arid and semi-arid regions, the use of plants resistant to salinity and drought stress can provide a new opportunity for harnessing the potential of the country's highly stressful climates. Therefore, this research aimed to investigate the effects of different levels of drought and salinity on the survival and morphophysiological characteristics of one-year-old Russian olive seedlings. An experimental pot study was conducted in a completely randomized block design with three replications and three observations, at three levels of drought (control 100%, 66%, and 33% field capacity) and four levels of salinity (zero as control, 4, 8, and 12 dS/m), in the greenhouse of the Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, from August to November over a period of 4 months. In this study, the content of chlorophyll and carotenoids was examined and measured. The results of this study showed that the main and interactive effects of drought and salinity stress on the measured traits were significant. The main and interactive effects of drought and salinity stress led to a decrease in chlorophyll and carotenoid content. The lowest levels of chlorophyll a (19.1 milligrams per gram leaf weight), chlorophyll b (44.0 milligrams per gram leaf weight), total chlorophyll (94.0 milligrams per gram leaf weight), and carotenoid content (39 milligrams per gram leaf weight) were observed.

This research was conducted to test the use of Iron slag without and with the combination of biochar and vermicompost under drought-stress conditions on coriander plants.

The experiment was conducted as a factorial based on a completely randomized design. The first factor included drought stress in 2 levels, and the second included fertilizer treatments in 7.

The results showed that the drought stress of 50% of the agricultural capacity caused a decrease in the fresh weight of shoot by 35%, fresh weight of roots (25%), chlorophyll a (29%), and chlorophyll b (25%), and total chlorophyll (26%), essential oil yield. (42%), phosphorus (39%), potassium (18%), magnesium (26%), Iron (40%), and an increase in malondialdehyde (34%) compared to the treatment. The treatments of different fertilizer sources increased shoot weight, root weight, chlorophyll content, relative leaf water content, essential oil yield, and leaf elements and decreased malondialdehyde and ion leakage. Based on the results of Iron slag treatment, especially in combination with vermicompost, it had an essential role in increasing plant yield under stress conditions. The correlation results between the traits showed that the yield of essential oil with shoot fresh weight (0.98), root fresh weight (0.87), chlorophyll (0.94), relative leaf water content (0.91), leaf phosphorus (95.0) 0), leaf potassium (0.86), leaf magnesium (0.92) and leaf Iron (0.83) had a positive and significant correlation with malondialdehyde (-0.93) and ion leakage (70) -0/) had a negative and significant correlation.

The biological and organic fertilizers application under drought stress can reduce the adverse effects of this global issue and improve plant growth and development parameters. Therefore, this study was conducted in two crop years of 2020-2021 and 2021-2022 in the climatic conditions of Chalus city, Iran. The split-factorial experiment was conducted in the form of a basic randomized complete block design with 3 replications. The main factor included irrigation deficit at three levels (100, 80, and 60% of water requirement) and the secondary factors included biological fertilizer (control, mycorrhizal fungus, and Enterobacter) and organic fertilizer (no use, 16, and 24 tons per hectare) in a factorial manner. The results of the mean comparison showed that the highest seed yield was observed in the second year under 100% irrigation and application of 24 t/h of organic fertilizer and mycorrhiza at the rate of 126.1 g/m2; Subsequently, theco- application of 80% water requirement and 24 t/h of organic fertilizer and enterobacter treatments in the second year caused the highest amount of 124.3 g/m2. Generally, the 60% water requirement reduced grain yield compared to other water requirements levels. According to the results of this study, the organic and biological fertilization under drought stress conditions can significantly improve the quantitative and qualitative yield of mung bean. Therefore, it is recommended that the organic and biological fertilizers can be applied in drylands to mitigate drought stress conditions, and improve the growth, yield and quality of mung beans.

Drought stress is a major limiting factor in global agricultural productivity, significantly affecting plant growth and yield by altering the plant’s morphological, physiological, and biochemical characteristics. These changes, including reductions in chlorophyll content, leaf water status, metabolite content, compromise plant development and crop output. One promising approach to mitigating the detrimental effects of drought stress is the use of biofertilizers, particularly arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria (PGPR). AM fungi establish symbiotic relationships with plants, improving water uptake and nutrient absorption, while PGPR enhance plant growth through various mechanisms, including the production of enzymes and stress-relieving compounds. Although numerous studies have demonstrated the efficacy of biofertilizers in improving plant resilience to drought, there is a significant knowledge gap regarding the comparative effectiveness of different types of biofertilizers. Specifically, it remains unclear whether fungal-based or bacterial-based biofertilizers are more effective, and whether liquid or powder formulations provide superior benefits. Moreover, there is limited understanding of the role of soil microbial processes, such as enzyme activities in the rhizosphere, in the plant’s adaptive response to drought conditions. This study aims to fill these gaps by investigating the effects of different biofertilizer types and formulations on drought tolerance in wheat, focusing on key physiological, biochemical, and microbial indicators.

For these purposes, a split-plot experiment was conducted based on a randomized complete block design with three replications under field conditions. The main plots consisted of three irrigation treatments: 100%, 85%, and 65% of the plant's water requirement, representing full irrigation, mild water stress, and severe water stress, respectively. The subplots included different biofertilizer treatments: no biofertilizer (F1), Pseudomonas fluorescens producing ACC-deaminase (F2), P. fluorescens without ACC-deaminase production (F3), AM fungus in liquid form (F4), and AM fungus in powder form (F5). Samples of flag leaves, roots, and rhizospheric soil were collected at the spike emergence stage. Several parameters were measured, including chlorophyll, carotenoid, proline, relative water content (RWC), membrane stability index (MSI) in the flag leaves, root colonization percentage, and rhizosphere enzyme activities such as acid phosphatase, alkaline phosphatase, and β-glucosidase. These indicators were chosen to evaluate both the direct effects of biofertilizers on plant drought tolerance and the associated microbial processes in the soil.

The results indicated that among the bacterial biofertilizers, only the application of F2 under severe water stress led to a 5% decrease in proline, a 6.5% increase in chlorophyll a, a 6% increase in total chlorophyll, a 16% rise in carotenoids, as well as a 10% increase in β-glucosidase activity and a 13% increase in acid phosphatase activity compared to the treatment without biofertilizer. The powder form of AM fungus (F5) proved to be the most effective in colonizing the roots of wheat. Specifically, root colonization with F5 was 13%, 19%, and 8% higher at irrigation levels of 65%, 85%, and 100% of the plant's water requirement, respectively, compared to the liquid form of AM fungus (F4). Overall, fungal biofertilizers outperformed bacterial biofertilizers in enhancing the physiological characteristics of wheat. For instance, under severe water stress, the F5 and F4 treatments increased RWC by 8.5% and 6%, MSI by 20% and 14%, chlorophyll a by 1% and 14%, and total chlorophyll by 12% and 10% compared to the treatment without biofertilizer, which were significantly higher than the bacterial biofertilizers. Among the fungal biofertilizer formulations, the powder form of AM fungus was more efficient than the liquid form in increasing wheat's drought tolerance. The powder form also improved β-glucosidase activity under both severe and mild water stress conditions and increased the activity of all the investigated enzymes under full irrigation. A stepwise linear regression model revealed that that among the biochemical and physiological characteristics of the flag leaf of the wheat, the amount of proline and carotenoid are the most important key variables affecting the β-glucosidase activity with relative importance index of 25.8% and 18.9%, respectively. Also, the amount of total chlorophyll and chlorophyll a had the greatest effect on the amount of alkaline and acid phosphatase activities.

The findings of this study underscore the superior effectiveness of fungal biofertilizers, particularly in powder form, in enhancing drought tolerance in wheat. The powder form of AM fungi was more efficient than the liquid form in promoting root colonization and increasing enzyme activity in the rhizosphere, leading to improved physiological and biochemical traits in the wheat plants. This formulation likely contains a greater diversity of AM fungal species, which may contribute to its enhanced performance. The positive feedback loop observed between rhizospheric enzyme activities and plant physiological traits suggests that biofertilizers, particularly AM fungi, can play a crucial role in improving the drought resilience of crops in water-limited environments.

In order to evaluate the effect of salicylic acid and zinc sulfate on quality and quantity characters of green cumin (Cuminum cyminum) under different irrigation regimes, a field study was conducted at Fatholmobin Agro industry, Kashan, Iran. A split factorial experiment based on randomized complete block design with three replications was used. The main plots considered irrigation regimes (irrigation after 70, 100 and 130 mm cumulative evaporation from class A evaporation pan), and sub-plots considered two level of salicylic acid application (control and 1 mM) and three levels of zinc sulfate (control, 30 and 60 Kg.ha-1) as factorial. The results showed that with the increase in the irrigation interval, the yield and yield components decreased and the percentage of cumin essential oil increased. The grain yield in irrigation after 70, 100 and 130 mm cumulative evaporation treatments was 2659, 19525 and 1009 kg/ha, respectively. The application of salicylic acid and zinc sulfate both under control conditions and moisture stress led to an increase in yield and yield components. Although by delay in irrigation from 70 to 100  mm cumulative evaporation from class A evaporation pan, the grain yield decreased by 6%, with the combined application of 60 kg/ha of zinc sulfate and salicylic acid while reducing the effects of drought, the essential oil yield increased by 6.5 kg/ha. It was concluded that by irrigation the cumin after 100 mm cumulative pan evaporation with combined use of 60Kg.ha-1 zinc sulfate and 1 mM salicylic acid, water could be saved by 21.5% while increasing the yield of essential oil, the yield of seeds may decrease slightly under these conditions.

Water is a critical factor for the growth and fruiting of the grapevines. Considering the water scarcity crisis in Iran and most parts of the world in recent years, it is necessary to apply methods such as deficit irrigation for the optimal management of water use in agriculture. It has been determined that by deliberately reducing water consumption in vineyards, it is possible to preserve the existing water resources and improve the water use efficiency.

A research was carried out in summer 2023 in a randomized complete block design with three replications on 8-year-old vines of the Turkmen-4 variety, to investigate the effect of deficit irrigation levels on the quantitative and qualitative traits and water use efficiency of grapevines. The vines were planted with 2 x 4 meter intervals, were trained as a vertical trellis on a bilateral cordon system, and the vineyard was irrigated by drip irrigation. The experimental treatments included full irrigation (providing 100% of vine water requirement; as control), 25% deficit irrigation (providing 75% of vine water requirement) and 50% deficit irrigation (providing 50% of vine water requirement). Irrigation of the vineyard started from May 22 and continued until November 6 at 7-day intervals, according to the conventional procedure. The water requirement of each vine in non-stressed condition was calculated by a class A evaporation pan based on reference crop evapotranspiration (ETo) and crop coefficient (Kc) throughout the season. Then, the amount of water for each treatment was determined according to the irrigation levels in the treatments and applied in volume form.

The amounts of water consumption of control, 25% and 50% deficit irrigation treatments were 5140, 3855 and 2570 m3 per hectare, respectively. The results showed that irrigation levels had a significant effect on the berries length, berries diameter, cluster length, cluster width, berries weight, cluster weight, sugar percentage, chlorophyll index, relative water content, midday leaf water potential, vegetative growth, vine yield, yield index and water use efficiency. The 25% and 50% deficit irrigation treatments caused a decrease of 7.2% and 14.2% of the berry length compared to full irrigation, respectively. Also, these treatments caused a reduction of 8.3% and 13.9% of the berry diameter, respectively. While the 25% deficit irrigation treatment had no significant effect on the berries sugar content (°Brix), the 50% deficit irrigation treatment caused a significant decrease (5%) in sugar content compared to the control. Both relative water content and midday water potential of the leaves decreased significantly with the reduction of irrigation levels. Reducing the level of irrigation led to a significant decrease in the SPAD index and vine vegetative growth. Increasing the intensity of deficit irrigation had a significant negative effect on yield components including berry weight, cluster weight, vine yield and yield index. The highest and lowest yields were obtained from full irrigation and 50% deficit irrigation, respectively but the effect of 25% deficit irrigation on yield reduction was not significant. Although the 25% and 50% deficit irrigation treatments caused a 5.8% and 27.5% decrease in vine yield, respectively but these treatments increased water use efficiency by 34% and 44.5%, respectively compared to the control. The lowest water use efficiency was related to the control (3.53 kg of fresh fruit per cubic meter of water used), while the water use efficiency of vines under 25% and 50% deficit irrigation was 4.73 and 5.10 kg of fruit per cubic meter of water, respectively. The 25% and 50% deficit irrigation treatments had a statistically significant difference with the control in terms of water use efficiency, but the difference between the two was not significant.

In the present study, reducing the volume of irrigation water led to a decrease in vine yield, but what is important is the low yield reduction rate compared to the amount of water consumption. The decrease in vine yield was 5.8% and 27.5%, respectively with a 25% and 50% decrease in water consumption. Also, with 25% and 50% reduction in water consumption, the yield index decreased by 6.1% and 27.3%, respectively. Meanwhile, the water use efficiency of vines increased by 34% and 44.5% in response to 25% and 50% deficit irrigation treatments, respectively. It is recommended to apply 25% deficit irrigation to increase the water use efficiency of Turkmen-4 grapes in climatic conditions of Malayer, but 50% deficit irrigation leads to a decrease in quality of grapes.

reenhouse conditions, the use of biochar on yield and yield components of cucumber and to determine the effect of water stress and biochar on cucumber yield components in Birjand region. Application of biochar in soil increases the yield of cucumber (Cucumis sativus) of Storm cultivar and the combined effect of water stress and biochar modulates the effect of water stress on reducing crop yield.

Due to the conditions in the greenhouse and the type of cultivation (stacks), this study was selected as a factorial in a randomized complete block design with three dehydration treatments and four biochar treatments. Drought stress has three levels of 100, 75, 50% water requirement. And biochar levels of zero, 2, 4, 6 grams per kilogram of soil are selected The type of cultivation is in the form of a stack or a stack in which a stack is selected and divided into equal plots. Based on the number of treatments and replications selected, 36 plots are required, each plot being 80 cm long and 40 cm wide. After preparing a suitable culture medium, two seeds were planted in each plot with a distance of 2 cm because if the seed did not germinate or was destroyed, another one could be used as an alternative. Then, all plots were irrigated automatically until the plants became four-leafed, and pest control operations were carried out equally and equally among all plots.

The results show that biochar had a significant effect on cucumber height, cucumber diameter, cucumber weight, plant height, number of leaves and stem diameter at 1% level. It can be seen that water stress at the level of 1% had a significant effect on cucumber height, cucumber weight, number of leaves and stem diameter. But its effect on cucumber diameter index and plant height was not significant. In this experiment, the interaction effect of biochar and water stress at 1% level had a significant effect on cucumber height and cucumber weight and at 5% level on cucumber diameter and stem diameter, but its effect on plant height and number of leaves was not significant.

Drought stress was significant on cucumber height, cucumber weight, number of leaves and stem diameter at 1% level and had no effect on cucumber diameter and plant height indices. • The best performance in plant height, cucumber weight, number of leaves and stem diameter at I100 level. Consumption of 6 grams of biochar per kilogram of soil at the level of water stress, 100% water requirement had the highest yield on growth indices (cucumber height, cucumber weight) and at the level of 5% on stem diameter and cucumber diameter indices. The use of biochar on the indices of stem diameter, cucumber diameter, cucumber weight, cucumber height, number of leaves and plant height was positive and significant and the use of 6 g of biochar per kg of soil in all indicators has the highest yield for cucumber plant. The interaction effect of water stress and biochar was significant on cucumber height and cucumber weight indices at 1% level and on cucumber diameter and stem diameter indices at 5% level, but the interaction effect of stress and biochar on plant height and leaf area indices was not significant.

Due to the limited quality of water resources and considering that the majority of the country is arid and semi-arid, it is important to cultivate plants with a high tolerance to drought and salinity. This research was conducted to determine the effect of different moisture levels on yield and yield components of quinoa (Chenopodium quinoa Willd.) under lysimetric conditions in the spring and autumn cropping seasons. Treatments included irrigation after draining 0.2, 0.4, 0.6, and 0.8 of the total available water (TAW). Irrigation was done based on the soil moisture depletion and the leaching requirement of about 20%. At the end, dry biomass, seed yield, and yield components were measured. The results showed that with an increase in the moisture depletion from 0.6 to 0.8 TAW, the biomass and seed yield had a significant decrease of 24 and 37% in the spring and 34 and 47% in the autumn cropping season, respectively. But the increase in moisture depletion from 0.2 to 0.4 and 0.4 to 0.6 did not cause a significant decrease in these traits. The results indicated that changes in moisture depletion levels caused significant differences in plant height (P<0.01), stem diameter, and 1000-seed weight (P<0.05) in spring cropping, but their effect on panicle length and width and the number of secondary stems was not significant. In the autumn cropping season, the results showed that changes in moisture levels caused significant differences in plant height and the 1000-seed weight (P<0.01), but the effect on other yield components was not significant.

Salinity is the main problem of the fields under irrigation in many regions of the world which has been caused the farmers encountered with some questions such as determining of the optimum depth of irrigation water by using of saline water, reuse of drained water from the agricultural fields and yield reduction that resulting in reduction revenue by using of saline water. Water shortage and unsuitable quality of irrigation water are two main factors which has restricted the crop production in many regions of Iran. Among environmental stresses, salinity stress is the main factor of crop reduction. Many physiological processes of plants such as germination, seedling growth, flowering and fruit ripening are decrease by increasing in salt concentration in soil and irrigation water. Deficit irrigation and soil or irrigation water salinity decrease the matric and osmotic potential in soil water content respectively, which are resulting in reduction of water absorption by plant roots. Camelina (Camelina sativa L. Crantz) is a plant with oil seed from Brassicaceae family that interest to its planting has increased in recent years. The causes of that are high tolerance of this plant to unfavorable environmental conditions and usage possible of it for many purposes. Appropriate usage of yield- salinity- water crop production functions can be improved agricultural water consumption management in regions with scarce of water resources. Crop production functions such as linear form, Cobb-Douglas, quadratic and transcendental function models were used to simulate relative grain yield of camelina. As the area study in this research namely Kashmar plain, has been forbidden for withdraw of groundwater and many agricultural deep wells in this area have high salinity water, in order to optimum management water consumption in agriculture, determining of the best water-salinity-yield production function for crops such as oil seed plants (canola, seasame and camelina) are essential. For the first time, camelina was planted in Kashmar natural resource and agricultural research center as pilot plan in 2021. As the compounded effects of salinity and water stress on camelina grain yield has been not investigated in this area, the objective of this research was to obtain the optimum crop production function as affected by drought stress and irrigation with saline water. A greenhouse experiment was conducted as a factorial in the form of a completely randomized design with three replications. The experiment treatments were four levels of salinity including drinking water S1=0.7, S2=4, S3=8 and S4= 12 dS m-1 and three levels of irrigation water including W1 (100% provided crop water requirement), W2=0.75W1 and W3=0.5W1 applied in a loamy sand soil texture with bulk density of 1.41 gr cm-3. Linear, Cobb-Douglas, quadratic and transcendental function models were used to simulate relative grain yield of camelina. In order to determine of optimum crop water production function, statistical analysis was done on obtained data and by determining of related statistics the role of each input was characterized quantitatively. For assessing of validation, the obtained functions, the statistics including maximum error (ME), root mean square error (RMSE), determining coefficient (R2), efficiency function (EF) and coefficient of residual mass (CRM) were used. The results showed that quadratic function model was the most appropriate model for estimating of grain yield of camelina under pot planting conditions in greenhouse. Marginal product (MP) and marginal rate of technical substitution (MRTS) indices of grain yield related to quality and quantity of irrigation water showed that with increase a centimeter of irrigation water depth (hypothesized salinity is constant), camelina grain yield increased 56.8 kg ha-1. Also, MP related to irrigation water salinity indicated that with increase a unit of salinity (hypothesized irrigation water depth is constant) camelina grain yield decreased 38.7 kg ha-1. According to findings of this research it could be said that 70 mm depth of irrigation water and EC less than 4 dS m-1 is suitable for achievement to optimum grain yield of camelina under pot planting conditions in greenhouse. It is noteworthy that further consumption of water by plant (almost 300 mm) and longer of growth period duration of plant in field compared to pot planting conditions in greenhouse caused to production function coefficients recommended in this study would not be applicable in field conditions and it is necessary that supplemental studies would be conducted for determining of optimum yield- salinity- water production functions of camelina under field conditions.

Optimal use and management of water resources is very important. Also, choosing the appropriate irrigation method plays a vital role in saving water consumption in the agricultural sector. Therefore, in the current research, the effect of the irrigation method on the simulation of sugar beet yield was investigated using the AquaCrop model. In this study, the effect of two methods of drip irrigation (tape) and surface irrigation (furrow) and three levels of irrigation water (50%, 75%, and 100% of the plant's water requirement) on the yield of sugar beet plants was investigated in Sarayan-Ayask region, Iran. A factorial experiment was conducted based on a completely randomized design with 4 replications in 2021-22. The results showed that irrigation method had a significant effect on leaf diameter, leaf length, leaf weight, tuber diameter, and tuber length and weight of sugar beet tuber. Also, according to the results, drip irrigation had greater effect than furrow irrigation on the studied traits. Then, the grain and biomass yield was simulated using the AquaCrop model and the simulated values were calibrated and verified using observational data. Calibration was done using two replications of 100% and 50% stress levels, and validation was done using the replication of 75% stress level. The NRMSE, RMSE, RD and R2 coefficients of the model calibration values showed that the simulated and validated values were close to each other and these values were more precise in drip irrigation than in furrow irrigation. Validation values of two irrigation methods also showed the ability of model in simulating grain yield and biomass.

In order to study the effect of deficit irrigation (DI) and partial Root-Zone Drying (PRD) on water productivity and photosynthetic characteristics of mungbean, a field experiment was conducted as a split-plot experiment in a randomized complete block design with three replications and nine treatments at the research farm, Ilam University during the growing season in 2021. Treatments included three levels of deficit irrigation (50, 70 and 100% of water requirement) as main plots and three irrigation methods including; usual irrigation, fixed partial root-zone drying, and alternative partial root-zone drying as subplots. The results showed that the effect of drought stress on water productivity, carboxylation efficiency, and photosynthetic water use efficiency was significant. Also, the Interactive effect of drought stress and irrigation method on water productivity and carboxylation efficiency was significant. The highest amount of water productivity, in all irrigation methods, was found in 75% water requirement treatment. The highest water productivity (0.49 kg/m3) was recorded with the alternative PRD method in 75 % of the water requirement level. There was no significant difference between alternative PRD and DI methods at 75 and 100 % of water requirement levels on water productivity. In severe drought stress, water productivity in the alternative PRD method was significantly higher than the other two methods. Therefore, in drought stress conditions, using the PRD method was effective in reducing the effects of drought stress.

Due to the climatic conditions of Iran, increasing water scarcity, and the effect of drought stress on the efficiency of irrigation water consumption and chemical fertilizers application, an experiment was conducted to investigate the effect of irrigation intervals (6, 9, and 12-day intervals), different levels of nitrogen fertilizer (200, 300, and 400 kg urea per hectare) and cultivation methods (on-ridge or heeling up and in-furrow) on yield and productivity of sugarcane as a factorial design based on randomized complete block design in 3 replications at Hakim Farabi Agro-Industry Company in Khuzestan province. The results showed that the maximum (106.73 tons/ha) and minimum (59.10 tons/ha) sugarcane yields were observed in 9-day and 12-day irrigation intervals, respectively. Also, the highest sugarcane yield (99.89 tons per hectare) was obtained in the treatment of 400 kg urea per hectare and the in-furrow planting method resulted in a higher yield compared to the on-ridge planting method. The highest water productivity in sugarcane stem yield and sugar production with 3.55 and 0.34 kg per cubic meter of applied water, respectively, was obtained in a 9-day irrigation interval. A significant increase in water use efficiency in sugarcane stem yield was observed in 400 kg urea/ha compared to the other two fertilizer levels. However, there was no significant difference in water productivity of sugar yield between different fertilizer treatments. The results showed that 6 and 9-day irrigation intervals in most of the studied traits were not significantly different. Therefore, using a 9-day irrigation interval is suggested in the studied area when the sugarcane cultivation area is high and the amount of available water is limited. In-furrow planting method can also be effective in reducing water consumption. Therefore, deficit irrigation and proper nitrogen fertilizer consumption can be very effective in sugarcane cultivation.

In order to evaluate of grain yield and fatty acids composition in peanut (Arachis hypogaea L.) oil as affected by supplementary irrigation and Salicylic acid, this experiment was performed as split plat based on randomized complete block design with three replications in experimental field of Agicutural and Natural Resources Research and Education Center of Guilan Province, Astara (Kanroud research station), Iran, during 2018 and 2019 cropping seasons. Four level of irrigation regimes including no irrigation (as control), irrigation at initial flowering stage, irrigation at pod formation stage and irrigation at initial flowering + pod formation stages and three levels of Salicylic acid such as 100, 200 and 300 µmol/l comprised experimental treatments, as main and sub plot, respectively. Drought stress dercreased grain yield, grain oil content, oil yield, protein yield, linolenic, stearic and bihenic fatty acids percent in peanut oil. But, grain protein percent, oleic, palmitic and arashidic fatty acids percent enhanced in response to drought stress. Foliar application of salicylic acid at the rate of 300 µmol/l improved all measured characteristics except stearic and bihenic fatty acids under both drought stress and supplementary irrigation conditions. The greatest grain yield (3450 kg/ha) of peanut was obtained in response to supplementary irrigation at initial flowering + pod formation stages along with Salicylic acid application at the rate of 300 µmol/l. Also, Salicylic acid application at the rate of300 µmol/l. showed the highest rate of oleic acid in peanut oil (60.98 %) under no irrigation (rainfed) condition. Hence, supplementary irrigation and foliar application of Salicylic acid could be recommendable in direction to enhance quantity and quality of grain and oil yield of peanut under similar climatic condition.

Today, by increasing industrial and agricultural activities and the subsequent increase in pollutants, soil and water pollution has become a serious environmental problem. The increase of pollutants in the soil in the conditions of dry climate and drought stress have adverse effects on the biological indicators. In this study the combined effect of cadmium at six levels (0, 5, 10, 20, 40 and 80 mg kg-1 soil) in the form of cadmium sulfate (CdSO4) and three irrigation intervals (2, 4 and 7 days) as a factorial experiment in the form of a completely random basic design with three replications was investigated on spinach (Spinosa oleracea) and lettuce (Lactuca sativa) in calcareous soil with silty clay texture. The obtained results showed that increasing the concentration of cadmium in the soil caused a significant decrease in the average dry weight of leaves and stems of lettuce and spinach. The average dry weight reduction percentage compared to the control at the highest level of cadmium was observed in lettuce leaves and stems as 63 and 46% and in spinach leaves and stems as 54 and 38%, respectively. Increasing the irrigation intervals decreased the dry weight of lettuce and spinach plants significantly compared to the control. The percentage of mean dry weight reduction in 4 and 7 days irrigation intervals compared to 2 days irrigation interval in lettuce leaf and stem was 23, 41, 31 and 63% and in spinach was 19, 39, 24 and 49%, respectively. The increase in cadmium levels increased the concentration of this element in the stem and leaves of lettuce and spinach plants, and by increasing irrigation intervals, the concentration and uptake of cadmium in the leaves and stems of spinach and lettuce decreased. The results of this research showed that the spinach plant absorb and transport cadmium metal more than the lettuce. The stress sensitivity index showed that the moisture stress has reduced the crop tolerance to cadmium. Based on the decrease in dry weight at different levels of cadmium, it can be said that the stem of two plants is more tolerant to cadmium than the leaf.

Reliable estimates of the seasonal applied water and irrigation performance assessment indicators under current irrigation and farm management are perquisites for improving water resources management. In this study, seasonal applied water and irrigation performance assessment indicators of winter barley were studied by monitoring 25 farms under actual conditions, in Ardabil Province (Ardabil, Namin, Nir and Kosar counties), Iran, during the growing season 2020-2021. The seasonal estimates of the net irrigation requirement during the growing season 2020-2021 and its 10-year average ranged from 476 to 652 mm and from 403 to 535 mm (with a mean of 530 and 449 mm), respectively, over the study farms. The total sum of seasonal applied water and effective precipitation (I + Pe) and the barley grain yield ranged from 266 to 716 mm and from 0.14 to 4.07 ton ha-1 (with a weighted average, WA, of 475 mm and 2.33 ton ha-1), respectively. As a result of limited irrigation water availability, 3-91% (with a WA of 52%) of the intended yield of irrigated barley in the study area (4.5 ton ha-1) was achieved. Physical and economic water productivity indicators were significantly (P < 0.05) affected by farmer's skill level, crop rotation, type of irrigation water source, and irrigation method. The results indicated that farms with surface water supply showed the highest vulnerability to drought periods. Improving the on-farm water management flexibility and mitigating the negative impacts of hot and windy days during the grain filling stage can improve water productivity indicators in the study area.

Rapeseed (Brassica napus L.) containes 40 – 46 percent oil and rich in unsaturated fatty acids such as oleic and linoleic and has a high nutritional value. The abiotic stresses such as drought stress causes to decline the quantitative and qualitative yield of many field crops in developing countries. In order to evaluate the foliar application effects of Zn and Fe micronutrients on growth and yiels of rapeseed under deficite irrigation condition, this experiment was carried out as factorial based on complete block design with three replications in two regions of Qazvin and Karaj, Iran 2019 cropping season. Three levels of irrigation regims including whole irrigation, cutoff irrigation from flowering stage and cutoff irrigation from silique stage and four levels of micronutrients including zero (as check), foliar application of Zn, Fe and Zn + Fe as 3×4 factorial as main plot and two varieties of rapeseed as sub plot comprised experimental treatments. Results showed that seed yield, relative water content and some fatty acids such as linoleic, palmitic and stearic deccreased in response to drought stress caused by cutoff irrigation from flowering stage and micronutrients deficiency and foliar spraying of Zn + Fe enhanced them equal 136.13, 8.20, 7.72, 12.87 and 22.55 percent, respectively. Some evaluated traits such as stomatal resistance, prolin, soluble carbohydrates and oleic, linolenic and erucic fatty acids increased under cutoff irrigation condition from flowerin stage compared to whole irrigation. Result showed that integrated application of Zn and Fe as foliar spraying through increasing of stomatal resistance and increasing of stomatal conductivity and relative water content caused to enhance seed yield of rapeseed under drought stress condition.

Drought and salinity stress are the most important limiting factors for plant growth. Selenium has been introduced as one of the useful elements against the destructive effects of stress. To the investigation of influence salinity and drought stress on water productivity and some characteristics of Mentha piperita L in the presence of selenium, an experiment on the split in time was performed in the Torbat-e Jam region, Iran in 2020, including two levels of cut (cut1 and cut2), three levels of irrigation (including full irrigation (100% of water requirement) = I1, I2=75% I1 and I3= 50% I1), three levels of Salinity (0, 50 and 100 mmol NaCl) and selenium factor in 2 levels (0 and 5 mg/l Na2SeO4). The result showed that fresh and dry weight, plant height, the number of leaves per plant, and the number of nodes decrease under salinity and drought stress. Generally fresh and dry weight, plant height, number of leaves per plant, number of nodes, Essential Oil percentage, and water productivity in the first cut was more than in the second cut. Also, foliar spraying of selenium (5 mgr/lit Na2SeO4) increased the above characteristics and also increased plant resistance against salinity and drought stress. The result showed with increasing salinity and drought stress respectively water productivity increased and decreased. the result showed that the percentage of essential oil increased by applying mild stresses in the form of deficit irrigation and then by applying intense stress, the percentage of essential oil decreased. Also result showed that the use of saline water in the conditions of drought stress caused intensification of reduction in fresh and dry weight, number of nodes and percentage of essential oil.

Water is one of the most important restrictive factors in the production of agricultural products worldwide. The aim of this research is to study the effects of different levels of irrigation and organic mulch on yield, water productivity, fresh weight, dry matter percentage, hardness, soluble solid content, titratable acid, and chlorophyll index of Granny Smith apple fruit at harvest. For this purpose, factorial experiment was performed in a randomized complete block design with three replications in 2019. Irrigation treatment were applied at supply levels of 100, 75 and 50 percents of tree water requirement (ETc) and organic mulch to thicknesses of zero, 4, 8 and 12 cm. The results showed that the highest average of fresh weights of fruit were allocated to 75 and 100 percent water supply levels and organic mulch treatment at thicknesses of 8, 4 and 12 cm had a significant positive difference in fresh weight of fruit compared to the control, respectively. The average yield of mulched trees was 11.52 percent more than control trees, the highest yield was obtained in treated trees with 8 cm of mulch. Fruit SSC and the firmness of fruit were improved at 50 percent irrigation. The interaction of 8 cm mulch treatment with 75 percent irrigation had the most amount of fruit acid. Both chlorophyll a, b and total decreased with increasing drought stress and improved with the application of mulch treatments .In addition, interaction of both experimental treatments, increased water productivity and benefit per drop unit area.

In order to evaluate the effect of different irrigation regimes on quantitative and qualitative yield of grain and oil in peanut as affected by Ethanol Alcohol, this experiment was performed as split plat based on randomized complete block design with three replications in experimental field of Agicutural and Natural Resources Research and Education Center of Guilan Province, Astara (Kanroud research station), Iran during 2018 and 2019 cropping seasons. Four level of irrigation regimes at 25, 50 and 75 and 100 mm evaporation from class A pan and three levels of Ethanol Alcohol such as 10, 20 and 30 % (v:v), comprised experimental treatments, as main plot and sub plot, respectively. Drought stress caused to decrease grain yield, grain oil content, oil yield, protein yield and inoleic acid, palmitic acid and arashidic fatty acids lin peanut oil. But, drought stress had positive effect on grain protein content, oleic acid and stearic fatty acids. The greatest grain yield (3275 kg/ha) was pbtained influenced by the interaction effect between irriation regim at 25 mm evaporation fron A pan and Ethanol application at thr rate of 20 % (v/v). Ethanol foliar application at thr rate of 20 % (v/v) showed the highest rate of oleic fatty acid (57.17 %) under irrigation regim at 100 mm evaporation fron A pan (sever drought stress). In this experiment, drought stress caused to decrease quantitative yield of grain (69.56 %) in peanut and enhancement of oleic acic synthesis under drought stress condition improved oil quality (13.93 %) in peant. Ethanol applicatiom led to improve the quantity and quality of grain and oil yield in peanut under bath irrigation and drought stress conditions. Hence, foliar application of ethanol could be recommendable in direction to enhance quantitative and qualitative yield of grain and oil in peant under similar climatic condition.