جستجوی مقالات مرتبط با کلیدواژه « کم‎آبیاری » در نشریات گروه « کشاورزی »

 Climate change predictions indicate that drought and extreme heatwaves will become more frequent and extreme in many regions. Drought is the main abiotic stress that severely reduces plant yield across the globe. Thus, this may have negative consequences for the agricultural soils, as it limits the availability of water and nutrients to soil microorganisms and plants that develop on these soils. To cope with this situation, the use of organic amendments is the best option. Recent studies have shown that the application of organic fertilizers can affect soil moisture and thus, mitigate the negative effect of climate change on that parameter. Organic amendments increase soil organic matter content thus improving soil physical, chemical, and biological properties, and therefore, can confer drought resistance to soils. The application of organic residues has been presented as a great strategy against soil degradation in semiarid environments. However, the interactions between organic amendments and drought in hollyhock plants are not fully known. Here, we evaluate whether the organic amendment influences the physiological traits of hollyhocks and soil properties under drought conditions.

 The experiment was conducted in the research field at Ferdowsi University of Mashhad, Iran. The experiment consisted of three factors (cultivars, organic amendments, and drought) with organic amendments and drought having four and three levels, respectively. Drought treatments were controlled by a TDR at 80, 60, and 40% FC. The three sources of organic amendments were used cow manure, rice hull and wheat straw. Seeds were planted in cocopeat, perlite, and peat mixture trays in the greenhouse with an average temperature of 20 °C and under a photoperiod of 14 hours of light and 10 hours of darkness with a light intensity of 400 μmol-1 m2. In the 5-6 leaf stage, seedlings were transferred in pots (18 cm high and 8 cm in diameter) containing field soil. The plants were transferred to the field with four different substrates (field soil, field soil + manure, field soil + rice hull, and field soil + wheat straw) and were exposed to drought stress for one month during the flowering stage. This analysis examined both the physical and chemical properties of the soil, including changes in the macroelements nitrogen, phosphorus, and potassium.

 Soil nitrogen changes were significantly affected by the interactions of ecotype with drought, ecotype with the medium, and drought stress with medium. The highest nitrogen changes were recorded in Mashhad ecotype under 80% FC. Nitrogen content in amended soil had an increasing trend during the experiment, but the amount of nitrogen had a decreasing trend in soil. In all media under stress, the amount of soil phosphorus was increased and the highest amount of phosphorus was observed in soil + manure at all irrigation regimes. The highest amount of potassium in both ecotypes was observed in soil + manure. The amount of potassium in amended soils under stress significantly increased, but in all organic amendments with increasing drought stress from 80 to 40% FC, the potassium content decreased. In both ecotypes, soil salinity was increased in all culture media. Han et al. (2016) stated that the amount of nitrogen, phosphorus, and potassium in the amended soil was higher than the substrates containing chemical fertilizer. The medium EC was alkaline at the end of the experiment and the salinity of the culture medium increased compared to the control. This study revealed a negative correlation between electrolyte leakage and dry weight in hollyhock plants. Furthermore, all measured physiological and growth parameters were significantly affected by the treatments. Notably, the Mashhad ecotype grown in soil supplemented with animal manure at 80% field capacity (FC) exhibited the highest levels of physiological traits (SPAD and relative water content) and growth index (dry weight).The application of manure + soil by providing macro elements reduces the negative effects of drought stress.

 The type of crops grown in arid and semi-arid regions should be reconsidered. Also, some plants with high water requirements should be replaced with plants with low and unexpected water requirements. Because hollyhocks are low-expected plants that grow well in drought areas, so they can be considered as suitable species for cultivation in low-input systems and can tolerate drought situations by 40% FC in amended soil.

In order to investigate the effects of drought stress and different LED lights spectra on yield, water productivity and morphologic characteristics of wheat plant, a factorial experiment was performed in the form of completely randomized design in 2022 in the university of Torbat-e Jam, The effects of drought stress include three levels (100, 75 and 50 percent of water requirements) and the effect of different light spectra including six levels (white, 70% red + 30% blue, 100% red, 70% blue + 30% red, 100% blue and 50% red + 50% blue) on wheat plant was investigated. The results showed that by applying drought stress to the amount of 75 and 50% of the water requirement of the plant, fresh weight of aerial parts, dry weight of aerial parts, root fresh weight, root dry weight, plant length, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, potassium, phosphorus and magnesium concentration decreased and water productivity increased by 18.52% and 27.94% respectively. Also, the results showed that among the different types of LED light spectra application, the highest amount of fresh and dry weight of aerial parts, fresh and dry weight of roots, plant length and water productivity in 70% red + 30% blue light and the highest amount of photosynthetic pigments parameters were obtained in wheat plant under 50% red + 50% blue light. the results showed that the highest concentration of potassium occurred in 100% red light, phosphorus concentration in white light and magnesium concentration in 50% red + 50% blue light.

Studies on the effect of planting pattern on yield and water productivity in potato production have a long history at the international and national levels. It is difficult to draw general conclusions and recommendations for the application of appropriate treatments due to the differences in treatments and research findings. Therefore, the objective of this study was to apply a meta-analysis approach to summarize the results of several investigations on the effect of planting patterns on yield and water productivity in potato production. Consequently, several scientific papers published by the international and national researchers on potato planting patterns were reviewed, screened and analyzed. Control and experimental treatments have been applied in studies on the investigation of the effect of planting pattern on yield and water productivity in potato production. The spacing of potato planting rows in different experiments including 60, 75, 120 and 150 cm has been reported as a single-row and/or two-row under drip and/or sprinkler irrigation systems. The average yield was 33000 kg ha-1 and water productivity was 5.46 kg m-3 in the control treatment with row spacing of 75 cm. Combined results showed that increased yield by changing the planting spacing from the 75 cm to 60 cm 33%, to 120 cm 18% and to 150 cm 8%, respectively. While, the application of planting spacing treatments on water productivity was not statistically significant. Minor positive effects were observed compared to the effect of control treatment. The most positive effect was in the planting spacing of 60 cm (10%). Changes in yield and water productivity in two-row cultivations compared to single row under drip system decreased by 7% , while increased yield and water productivity were 4.6% and 16% under sprinkler system, respectively. Studies on the effect of planting pattern on yield and water productivity in potato production have a long history at the international and national levels. It is difficult to draw general conclusions and recommendations for the application of appropriate treatments due to the differences in treatments and research findings. Therefore, the objective of this study was to apply a meta-analysis approach to summarize the results of several investigations on the effect of planting patterns on yield and water productivity in potato production. Consequently, several scientific papers published by the international and national researchers on potato planting patterns were reviewed, screened and analyzed. Control and experimental treatments have been applied in studies on the investigation of the effect of planting pattern on yield and water productivity in potato production. The spacing of potato planting rows in different experiments including 60, 75, 120 and 150 cm has been reported as a single-row and/or two-row under drip and/or sprinkler irrigation systems. The average yield was 33000 kg ha-1 and water productivity was 5.46 kg m-3 in the control treatment with row spacing of 75 cm. Combined results showed that increased yield by changing the planting spacing from the 75 cm to 60 cm 33%, to 120 cm 18% and to 150 cm 8%, respectively. While, the application of planting spacing treatments on water productivity was not statistically significant. Minor positive effects were observed compared to the effect of control treatment. The most positive effect was in the planting spacing of 60 cm (10%). Changes in yield and water productivity in two-row cultivations compared to single row under drip system decreased by 7% , while increased yield and water productivity were 4.6% and 16% under sprinkler system, respectively. Studies on the effect of planting pattern on yield and water productivity in potato production have a long history at the international and national levels. It is difficult to draw general conclusions and recommendations for the application of appropriate treatments due to the differences in treatments and research findings. Therefore, the objective of this study was to apply a meta-analysis approach to summarize the results of several investigations on the effect of planting patterns on yield and water productivity in potato production. Consequently, several scientific papers published by the international and national researchers on potato planting patterns were reviewed, screened and analyzed. Control and experimental treatments have been applied in studies on the investigation of the effect of planting pattern on yield and water productivity in potato production. The spacing of potato planting rows in different experiments including 60, 75, 120 and 150 cm has been reported as a single-row and/or two-row under drip and/or sprinkler irrigation systems. The average yield was 33000 kg ha-1 and water productivity was 5.46 kg m-3 in the control treatment with row spacing of 75 cm. Combined results showed that increased yield by changing the planting spacing from the 75 cm to 60 cm 33%, to 120 cm 18% and to 150 cm 8%, respectively.

The economic importance of quinoa is not only due to the possibility of using the seeds as a food product characterized by a similar composition and use as consumer cereals but the species can also be managed as a leafy vegetable with high nutritional value and similar uses, such as, for example, spinach. Drought is another environmental stressor for plants subjected to severe water stress, especially in semi-arid and arid environments. Water scarcity poses a considerable challenge to crop production, leading to a notable reduction in crop yield. Quinoa, however, boasts low water requirements and demonstrates resilience in drought conditions. Even during dry periods, quinoa can effectively sustain leaf area and regulate photosynthetic activity. This resilience is facilitated by structural characteristics such as small, thin-walled cells, tissue flexibility, low osmotic potential, and controlled leaf area reduction through dehiscence. Other quinoa features for sustaining turgor pressure through osmotic adjustment during drought stress include inorganic ion buildup (e.g., Ca, K, and Na) and improved organic element synthesis (carotenoids and proline). Quinoa genotypes have several drought-resistance mechanisms, enabling this crop to grow and develop under severe drought conditions. 

To evaluate the effect of moisture levels on some quinoa cultivars biochemical traits, four separate experiments were conducted in a factorial layout based on randomized complete block design with three replications in two regions (Birjand and Sarbisheh) and two planting dates (March and July/August) in 2018-2019. The experimental factors included five moisture levels (25, 50, 75, 100, and 125% of crop water requirement) and three quinoa cultivars (Titicaca, Giza1, and Redcarina). Some quinoa physiological and biochemical traits were evaluated by composite analysis at the 50% flowering stage and the effects of planting date and location were considered fixed.

The results showed that in August/July cultivation, the characteristics of RWC, electrolyte leakage, sodium percentage, potassium percentage, chlorophyll a, carotenoids, proline content, and total soluble carbohydrate of leaves were increased by 17.10, 74.62, 95.51, 31.9, 3.53, 38.65, 94.19 and 9.30% respectively and chlorophyll b content decreased by 13.15% compared to March culture. Also, in Sarbisheh, RWC, electrolyte leakage, potassium percentage, and leaf carotenoids are respectively 3.53, 38.65, 94.19 and 9.30% more than Birjand, but sodium percentage, chlorophyll a, chlorophyll b, proline and total soluble carbohydrates of leaves were 4, 1.88, 15.67, 51.02 and 30.41% less than Birjand, respectively. In most of the studied traits, the Giza1 cultivar had higher quality traits. Severe water scarcity resulted in an elevation of certain biochemical traits in quinoa leaves. Specifically, as moisture levels decreased from 125% to 25% of the water requirement, there was a significant increase in electrolyte leakage, sodium and potassium percentages, chlorophyll a and b, carotenoids, proline, and total leaf soluble carbohydrates by 24.50%, 37.84%, 35.89%, 24.83%, 59.12%, 48.75%, 51.58%, and 36.71%, respectively. However, the relative water content (RWC) decreased by 17.70%. Notably, there were no significant differences observed between the 125% and 100% levels of water requirement for most of the analyzed traits.

In general, with the significance of the triple interaction of planting date × location × cultivar, as a result, the reaction of each variety depends on the planting date and location of its planting. But in general, most of the quinoa leaf physiological and biochemical traits increased in August/July cultivation. In Birjand, due to the higher average temperature and other climatic parameters compared to Sarbisheh, and probably understanding the heat stress, traits such as photosynthetic pigments, proline, and soluble carbohydrates had higher values. In this research, the Giza1 was superior to the other two cultivars, and moisture stress caused a significant decrease in the water content of the leaves and a significant increase in quinoa leaves quality traits.

Due to the location of Iran in arid and semi-arid regions and according to the quantitative and qualitative limitations of water resources, optimal management and volumetric delivery of water is important in irrigation and drainage networks. In this regard, it is necessary to estimate the water requirement of crops accurately and provide adequate water to farmers. Remote sensing technology provides facilities that can be used to obtain different layers of information at the lowest cost in the fastest time. Accordingly, many researchers have used remote sensing data to monitor vegetation cover, provide land use maps, estimate crop evapotranspiration and have declared this technology as appropriate tool for such studies. Based on the previous studies, it is observed that low researches has been conducted to investigate the crop evapotranspiration considering the crop water requirement. Therefore, the most important objectives of this study are: provide the cropping pattern and land use maps using Sentinel 2 satellite images, determination of the water requirement for the delivery points of irrigation network, determination of the actual evapotranspiration of the crop cover using SEBAL algorithm and Landsat 8’s images and finally evaluation of the water supply and management in the Mahabad irrigation and drainage network. In order to determine the cropping pattern of the Mahabad irrigation and drainage network, Sentinel 2 images have been used related to the 2018-2019 crop year. The images were examined in terms of the region of syudy and the percentage of cloudiness and after selecting the appropriate images, pre-processing operations including radiometric and atmospheric corrections were applied on them. Then, the NDVI index was calculated based on selected images. On the other hand, after determination of the classification classes, the phenological cycle of crops were examined for each class and spectral pattern of crops was determined during the growing season. Training samples were selected for supervised classification using the existing maps, Google Earth images, creating images with false color composites and considering the growth pattern and some of them were also considered for validation of the classified map. Then, the cropping pattern map was obtained by using the SVM classification algorithm. After generating the crop classification map, the water requirement of the different classes was determined based on the Penman-Montith evapotranspiration method, applying plant coefficients and irrigation application efficiency at the volumetric water delivery points. Finally, the actual evapotranspiration rate of the study area calculated based on the SEBAL algorithm and compared with the net water requirement map. Based on the results, kappa coefficient and overall accuracy of the classified map were determined to be 0.953 and 91%, respectively. The area of the planted agricultural farms was equal to 10594 hectares and 1576 hectares of farms were without planting. The area of orchard farms was equal to 6786 hectares and the area of sugar beet, wheat, alfalfa and corn lands were obtained to 998, 1839, 693 and 278 hectares, respectively. Thus, the net irrigation water requirement was equal to 71 million cubic meters and the gross irrigation water requirement was calculated equal to 161.36 million cubic meters, considering the irrigation efficiency of 44%. On the other hand, the evaluation of the SEBAL evapotranspiration maps during the growing season indicated that the total amount of evapotranspiration was equal to 79.78 million cubic meters, and this amount was 14% higher than the net irrigation water requirement. Finally, according to the crop classification map and based on the comparison of the net irrigation water requirement and evapotranspiration maps, the water consumption in the Mahabad irrigation and drainage network was evaluated. It turned out that in the upstream farms of the network or close to the Mahabad River, the Water consumption was more than net water requirement and downstream areas were faced to deficit irrigation due to lack of sufficient water.Finally, based on the results of this study, it was observed that by using the capabilities of satellite images and remote sensing, it is possible to monitor and evaluate the condition of agricultural farms on a large scale with acceptable accuracy. Also it is possible to improve the management of water supply and water use efficiency in irrigation and drainage networks by creating up-to-date land use maps, determining net and gross irrigation water requirment and comparing with actual evapotranspiration maps.

Maize is one of the most productive grains following wheat and rice. In this regard, The so-called low-irrigation is considered as a method to save and manage water consumption. One of the low-irrigation practices is an irrigation method under which only a part of the root is irrigated. improve the soil condition is the use of organic fertilizers, including biochar. research was aimed to investigate the effect of different partial root irrigation treatments at two levels of 65 and 55 percent and to compare them with full irrigation. It was also aimed to use and compare different levels of biochar applications (0, 6 and 12 tons per hectare) on yield and yield components of maize in two cropping seasons. The yield components, grain yield and biomass of maize plants were measured after harvesting. The harvest index as well as the leaf area index was also calculated. The obtained results indicated that the treatment of 65 percent water demand was not significantly different from the full irrigation treatment in terms of grain yield. The increased quantity of applied biochar was led to increasing the maize seeds, so that, the treatment using 12 tons of biochar per hectare has the highest seed yield . The treatment without biochar has the lowest seed yield . The weight of 1,000 seeds in the treatment using 12 tons per hectare of biochar was 40 percent and 10 percent higher than the treatments without biochar and the one with 6 tons per hectare of biochar, respectively.

Camelina is an oilseed plant that could produce proper yield in arid and semi-arid areas with low water consumption. To investigate camelina response (Sohail cv.) to application of different amounts of irrigation water, this study was conducted in 2022-23 in Khatam District, Yazd Province. Treatments included drip tape irrigating based on 100% (full irrigation as control), 75% and 50% of full irrigation. Results showed that the effect of irrigation treatments on biological yield, grain yield, harvest index, plant height and protein percentage of camelina was significant (p<0.05). However, by reducing the volume of irrigation water, biological yield decreased significantly, such that biological yield of 75% and 50% treatments decreased by, respectively, 18.3% and 46% compared to the control treatment. The highest grain yield (2373.3 kg ha-1) was obtained with the application of 2384 m3 ha-1 irrigation water (control). By reducing the amount of irrigation water by 75% and 50%, grain yield decreased by 31.4% and 40.0%, respectively. The harvest indices were 22.6%, 19.0% and 25.1% for 100%, 75%, and 50% treatments, respectively. The highest plant height was 90 cm for the control treatment. The water productivity ranged from 0.88 kg m-3 for 75% treatment to 1.04 kg m-3 for the full irrigation. The highest proline content was observed for the treatments of reducing the volume of irrigation water, in which the amount of proline increased by 1.4 times compared to the control treatment. The results showed that the amount of irrigation water required for camelina was lower compared to the common winter crops, especially in tape irrigation method. Therefore, this plant could be used as a low water-demanding for delayed planting in winter season.

Leaf area index (LAI) is one of the most important parameters in plant growth studies, which has a direct relationship with the amount of light absorption, photosynthesis, plant physiological indicators, yield, etc. to be In this study, different growth functions such as Gompertz, Gaussian, polynomial and logistic were used to model silage maize leaf area index (as a dependent variable) based on growth degree days (as an independent variable). The studied treatments included pulse irrigation and continuous irrigation, each at three levels of MAD equal to 100, 80 and 60%, which were applied as a completely randomized block design. The results showed that based on R2, NRMSE and EF parameters, all four used models were highly accurate and precise in estimating the leaf area index during the growth period. Among the four investigated models, the logistic model showed the best result among different irrigation managements and levels. Also, this model had the highest efficiency among both continuous and pulse irrigation treatments, in MAD equal to 100%. The results of this study can be a basis for monitoring crop growth and evaluating different managements in the water, soil and plant chain, and finally a useful tool for management and planning to achieve food security.

As it has been for several years, drought conditions in various regions of Iran, including the central part of Marvdasht city in Fars province, have been very noticeable and have led to a severe decrease in the quantity and quality of groundwater, resulting in severe restrictions on agricultural production. Therefore, the farmers in the region have spontaneously turned to planting drought-resistant trees such as olives and pistachios. On the other hand, due to the significant reduction in the quantity and quality of groundwater in the study area, the quantitative and qualitative parameters of the fruit of the region's agricultural products, especially olive trees, which are irrigated under these conditions, are effective. It can be said that the quality parameters of olives increase with low irrigation and high salinity (to a tolerable extent). On the other hand, water and salinity stresses will have different effects on the performance of the mentioned plants. In this region, olives are used in two forms, canned and oil production. The amount of olive oil is often dependent on the growing conditions and fruit ripeness, and how the oil accumulates. The amount of oil in the dry matter of the fruit during the fruit ripening period (second fruit growth period) and its accumulation increases until the onset of dark purple. The quantity and quality of irrigation water affect the time and amount of oil accumulation, as well as the quality of olive oil. Also, the shelf life of olives in canned conditions and the shelf life of the aroma and taste of extra virgin olive oil are important features that will be controlled and examined by studying the density of olives during the fruit growth period. Therefore, the main purpose of this study is to investigate the changes in the density of olives during the fruit growth period under conditions of low irrigation and salinity stress.

The study area is located in the central part of Marvdasht city in Fars province, Iran, at geographical coordinates '693196;3303288' with an elevation of 1620 meters above sea level. According to the De Martonne method, the climate of the region is semi-arid and the dominant wind direction is eastern. Two years (2020-2021) of field experiments were conducted to study olive fruit density in a 20-year-old olive orchard (Roghani variety). The experiment utilized a factorial layout in a randomized complete blocks design with three replications. Five irrigation levels (I1-I5) were tested, ranging from 25% to 125% of olive water requirement. Three saline water levels (S1-S3) were also included, with S1 being saline well water with an electrical conductivity of 3.5-7.5 dS/m, S2 being a combination of 50% well water and fresh water, and S3 being fresh water. The weight and volume characteristics of olive fruits were examined and measured at seven different periods, starting from the fruit's appearance in June until its harvest in December for oil production. The I5S3 represented the control treatment.

Despite the fact that poor quality and quantity of irrigation water (S1, I1, and I2) will result in a decrease in the weight and volume of olive fruit, it is beneficial for improving the quality of suitable oil and will have an impact on the density of olive fruit. Oil production in olive fruit, which occurs during the second period of fruit growth, has a significant role in the density of the fruit. If the volume of fruit does not change (in the case of low-quality and low-quantity irrigation water), due to the increase in oil in a specific volume, it will lead to an increase in fruit weight and consequently an increase in olive density. The increase in density during the first growth period is accompanied by the production of dry matter in the fruit. A decreasing trend in the density of olive fruit can be observed in all irrigation treatments and different salinity levels in both consecutive years. The study found that normal irrigation water (I4 and I5) and appropriate quality (S2 and S3) increase the weight and volume of olive fruit and alter the density of olive fruit. The interaction effect of salinity and irrigation on the density of olive fruit was significant (5%) in both years. In 2020, changes in fruit density during the second period of fruit growth at salinity level (S1) were more pronounced in different irrigation treatments from I2 to I5 compared to other salinity levels (S2 and S3). The highest and lowest density values in 2020 were I2 and I3, respectively. The highest fruit density (1.1356 gr/cm3) was observed in the high salinity level (S1) and low irrigation treatment (I2). In 2021, the highest fruit density (1.1105 gr/cm3) in the first period of growth is related to S1, and in the second period of growth, it decreases compared to S2 and S3. In the same year, I1S3 had the highest value (1.0753 gr/cm3) and I5S3 had the lowest value (0.9899 gr/cm3) in the second stage of olive fruit growth. Although low quality and quantity of irrigation water (S1, I1 and I2) reduces the weight and volume of olive fruit, it is suitable for improving the quality of oil and will affect the density of olive fruit.

The response of Thymus vulgaris and Zataria multiflora to mycorrhiza fungus inoculation (inoculation and non-inoculation with Funneliformis mosseae) at different irrigation levels (irrigation 100% of field capacity (100% FC, control or no stress); 75% FC (moderate stress); and 50% FC (severe stress); was investigated in greenhouse conditions. The results showed that inoculation with mycorrhiza led to improvement of root volume by 100%, root dry weight by 159%, shoot fresh and dry weight by 77% and 96%, and water use efficiency by 98% under 100% FC and in some cases under 75% FC. The results of evaluating the mycorrhizal inoculation effect in different irrigation conditions, also showed that the effectiveness of mycorrhizal inoculation decreased dramatically with increase in stress intensity. Phosphorus (P) content of the shoot of T. vulgaris and Z. multiflora decreased with drought stress application. In addition, mycorrhizae inoculation increased root P content by 14% in T. vulgaris. In Z. multiflora, inoculation with mycorrhizal improved P content by 63% compared with non-inoculation under severe stress. While in T. vulgaris, root P uptake was improved (170%) by mycorrhizal inoculation under normal and mild stress conditions, mycorrhizal inoculation did not show the efficiency to improve P uptake under severe stress condition. Meanwhile, in Z. multiflora, P uptake was improved by 75% and 215%, respectively in mycorrhizal inoculation under 75% and 50% FC. This can be one of the most important reasons for reducing the shoot to root ratio by mycorrhizal inoculation under severe stress conditions.

Currently, about 90 percent of the population of developing countries live in arid and semi-arid areas. Therefore, it is necessary and inevitable to identify the key and effective factors on the growth of agricultural products . The purpose of this research is to evaluate the accuracy and efficiency of the latest version of the AquaCrop model for simulating seed yield, biomass and water productivity efficiency of safflower in the form of a randomized complete block design with one control treatment (Conventional irrigation) and four deficit -irrigation treatments, including (RDI80, RDI60: reduced irrigation adjusted by supplying 80 and 60% of soil moisture deficiency) and (PRD80, PRD60: fixed partial root-zone drying irrigation with supply of 80 and 60% of soil moisture deficiency) and with four repetitions in Khuzestan University of Agriculture and Natural Resources was conducted. In order to evaluate the reliability of the model, some statistical indicator including the average normalized root mean Square error (NRMSE), the Coefficient of Residual Moss (CRM), Coefficient of Determination (CD), maximum error percentage (ME), Wilmot index (d) and the modeling efficiency (EF) was used. The statistical index (NRMSE) was obtained for seed yield (4.14), biological yield (10.16) and water productivity efficiency (4.9) and showed that the accuracy of the model in simulation is excellent. The results of the model validation show the accuracy and efficiency of the model in simulating seed yield, biomass and water productivity efficiency, and therefore, this model can be used to manage safflower irrigation in different states of deficit irrigation.

The effect of magnetic and superabsorbent water was investigated on some morphophysiological traits and performance of cumin under a low irrigation regime.

An experiment was conducted in the agricultural year of 1399-1400 in the research fields of the Faculty of Agriculture of Shahrood University of Technology in two districts of Rahnjan and Garman of Shahrood city in a factorial format in the form of a randomized complete block design with three repetitions. Irrigation water type treatment at two levels (normal and magnetic) and locations (Rahanjan, Garman) with different climatic conditions and altitude above sea level as the main factor and superabsorbent treatment at three levels (zero, 100 and 200 kg/ha) as a secondary factor. Was considered. In all treatments, irrigation was applied based on 100% of plant water needs.

The results showed location, type of irrigation and different concentrations of superabsorbent had a positive and significant effect on the growth characteristics. In the Rahnjan region, due to the climatic conditions and higher average annual temperature and the treatment of 100 and 200 kg/ha of superabsorbent and the use of magnetic water, the highest amount of plant height, percentage and yield of essential oil and protein, soluble carbohydrates were observed.

According to the results, most of the traits in the Rahnjan region had higher values than in the German region, and plant cultivation in the Rahnjan region is economical.

The interaction of genotype with the environment provides the possibility of selecting stable genotypes for a wide range of environments. Evaluation of the interaction of genotype with the environment is necessary to increase the efficiency of selecting varieties with high and stable performance in a wide range of different environments. The objectives of this paper are: (1) evaluating the stability of 60 potato genotypes for tuber yield in two years using parametric and non-parametric stability methods, (2) identifying genotypes with good and stable performance when evaluated in variable environments and (3) investigating the relationship and correlation between stability statistics of tuber performance under water deficit conditions in Iran.

To evaluate the performance stability and adaptability of the 60 potato genotypes, two cultivars and 58 advanced clones, 17 parametric and non-parametric statistics were evaluated for tuber yield across eight environments during the 2018-2019 growing seasons. The genotypes were evaluated under normal and water deficit conditions in Karaj and Ardabil. In this study, the parametric analysis for yield was determined by such parameters as regression coefficient (bi), environmental variance (Si2), coefficient of variation (CVi), deviation from regression (sdi2), and Wricke’s ecovalence (Wi2), The non-parametric analysis included Nassar and Huhn's statistics (S(1) and S(2)), Huhn's equation (S(3) and S(6)), Shukla’s stability variance (σ2i), Plaisted and Peterson’s (θi), Thennarasu’s non-parametric (NP(1), NP(2), NP(3), and NP(4)), and Kang’s rank-sum (KR) parameter. Parametric and non-parametric statistics are used by agronomists and plant breeders. Currently, researchers are interested in applying several stability statistics to obtain the desired results, crucial for the selection of stable varieties

Composite variance analysis showed that the effect of place and year as well as the effect of genotype are significant. The interaction effect of year × location × genotype was significant at the probability level of 1%. The genotype effect was also significant at the 1% probability level. The interaction effect of genotype x location and genotype x year was not significant, which indicates that the average performance of genotypes is not different in different locations and years. Grouping of genotypes based on average performance and parametric and non-parametric stability statistics showed that genotypes are divided into four main groups. In general, based on the average rank of parametric and non-parametric stability parameters, genotypes G31, G21 and G36 had the least changes and were recognized as the most stable genotypes, and therefore they can be introduced as stable genotypes. The results of stability statistics and cluster analysis showed that G31, G21 and G36 genotypes can be introduced as stable and compatible genotypes.

Our results showed that G21, G31 and G36 genotypes contributed the least to the genetic × environment interaction (G*E) and were considered as stable genotypes under water deficit conditions. The different parametric and non-parametric stability procedures can be proposed to select drought tolerant genotypes under different environments conditions; these procedures could be useable for recognition of the best genotypes under drought stress conditions. Therefore, the analysis of yield stability could be utilized in combination with parametric and non-parametric methods to evaluate and identify drought tolerance genotypes. Dendrogram results confirmed each other with the results of parametric and non-parametric statistics. While G49, G51, G53 and G56 genotypes with the highest values were the most unstable genotypes.

Water is the most important factor limiting agriculture in the country. For this purpose, the effect of two irrigation methods (basin irrigation and tape irrigation) and three irrigation levels (50, 75 and 100 percent of the plant's water requirement) on the performance of edible onion plants in Aysk city, which has a relatively hot and dry climate, was studied. Was investigated. This research was done factorially in the form of randomized complete block design with four replications in two crop years 2017-2018. The results showed that the yield of onion under the influence of different levels of irrigation, the highest effect is in the yield related to the treatment of 100% water requirement and the lowest related to the treatment of 50% water requirement. Also, in terms of onion water consumption efficiency, it was found that Tape irrigation method with an average of 4.69 kg per cubic meter of water is 45.4% more than the basin method with an average of 2.56 kg per cubic meter of water. Also, the effect of different levels of irrigation on the efficiency of water use in 100% water demand with an average of 4.64 kg per cubic meter of water was not much different from the treatment of 75% water demand with an average of 17.4 kg per cubic meter of water. As a result, tape irrigation with a stress level of 75% of the plant's water requirement is the most appropriate method and irrigation water level for onion plants in this region.

Clover is considered as one of the most important forage crops of the leguminous family which is appropriate for temperate and humid areas. Insufficient water can severely affect the production of forage legumes leading to a reduction in yield based on the severity and duration of drought stress. Due to the relative sensitivity of clover to drought stress, the yield of this crop is affected by water scarcity, especially in arid and semi-arid regions. One of the effective solutions in the field of plant breeding for drought resistance is to identify stress-tolerant genotypes. This study aimed to compare the forage yield and water productivity of Persian clover genotypes under full irrigation and drought stress conditions, as well as evaluate their drought tolerance. The experiment was conducted as a split plot based on a randomized complete block design with three replications at the Seed and Plant Improvement Institute, Karaj, Iran, during the 2017-18 and 2018-19 cropping seasons. Irrigation regimes at two levels (full irrigation and deficit irrigation with supply 100% and 75% of clover water requirement, respectively) as the main factor and Persian clover genotypes at five levels (cultivar Pars, and ecotypes Zabol, Aleshtar, Eghlid, Harati) as sub-factor were evaluated. Each subplot consisted of four rows with a length of five meters and 50 cm between rows. The planting operation was carried out manually on September 11 of each year with 20 kg ha-1 seeding rate. The volume of irrigation water was determined by the Penman–Monteith method and the counter meter was used to accurately measure and control the amount of applied water. In the first and second cropping seasons, the total volume of irrigation water used were equal to 10125 and 11985 for full irrigation and 7594 and 8989 for deficit irrigation conditions, respectively. In this study, the fresh forage and dry matter yields, irrigation water efficiency for production of fresh forage and dry matter, the days to flowering, and drought tolerance indices were investigated. For all three cuts, clover cultivars were harvested at the 10% flowering stage. To determine the fresh forage yield, the middle four rows of each plot were harvested and weighed. To determine the dry matter yield, fresh samples (2 kg plot-1) were randomly selected and dried in a forced-air oven at 65 °C. Irrigation water-use efficiency was calculated from the ratio of yield to the amount of water consumed. The combined analysis of variance was performed using SAS9.1 and the means were compared by the LSD method at P < 0.05. The fresh forage and dry matter yields in the first, second and third cuttings, as well as their total and the irrigation water-use efficiency for forage and dry matter production were significantly affected by the year × irrigation × genotype interaction. Ecotype Harati had the highest total fresh forage and dry matter yields during three cuts (91.19 and 13.02 ton ha-1, respectively) in full irrigation conditions, whereas, under deficit irrigation conditions, the maximum total fresh forage and dry matter yields (68.07 and 10.79 ton ha-1, respectively) were obtained by ecotype Zabol. The maximum water-use efficiency (1.455 kg dry matter m-3) was obtained in the second year and by ecotype Zabul under deficit irrigation conditions, whereas the minimum efficiency (0.899 kg dry matter m-3) was recorded in the first year under full irrigation conditions and in the ecotype Zabol. Drought stress treatment in genotypes Pars, Aleshtar, Eghlid, Harati and Zabol compared to full irrigation caused a decrease in dry matter yield by 24.0, 21.7, 23.4, 23.8 and 11.9%, respectively. Among the drought tolerance indices, tolerance index (TOL), stress sensitivity index (SSI), yield stability index (YSI) and relative stress index (RSI) had the highest correlation with yield under full and defecit irrigation conditions. Based on the mentioned indices and principal components analysis (PCA), the ecotype Zabul, followed by ecotype Eleshtar were identified as the most tolerant genotypes to the defecit irrigation stress. Overall, the results of this experiment demonstrated that in the irrigation water availability conditions, the ecotype Harati and in the water limitation conditions, the ecotype Zabol are recommended for cultivation in the semi-arid regions of the country.

This research was conducted in order to investigate the interaction of different levels of irrigation and nitrogen fertilizer on the yield of Forage Corn in Khorramabad. The experiment was conducted as factorial in a randomized complete block design with three replications. The first factor consisted of four irrigation levels including I125 (125 Percent of water requirement), I100 (100 Percent of water requirement), I75 (75 Percent of water requirement), and I50 (50 Percent of water requirement) and the second factor consisted of three levels of nitrogen fertilizer including N400 (400 Kg/ha), N250 (250 Kg/ha), and N100 (100 Kg/ha). Based on the evaporation pan method, the total irrigation requirement for treatments I125, I100, I75 and I50 during the period were 761, 642, 524 and 406 mm, respectively, which were more than the amount of water requirement reported in the national water requirement document of plants.The result showed that the maximum amount of wet and dry matters, plant height, leaf area index which were 80 and 21.2 tons per hectare, 9595 mm2 and 220 cm, respectively, were obtained in I125N400 treatment, which had a significant increase (5 Percent) compared to the control treatment (I100N250). The minimum amount of these traits which were 30 and 10.64 tons per hectare, 7096.133 mm2 and 100 cm, respectively, were obtained in I50N400 treatment, which had a significant decrease (5 Percent) compared to the control treatment (I100N250). It was found from the results of this research that at the levels of I125 and I100, the values of wet matter and leaf area index were increased as the amount of nitrogen fertilizer increased. At irrigation levels of 75 Percent and 50 Percent of water requirement, increasing the amount of fertilizer did not cause significant changes in the measured traits. In this research, the maximum value of water productivity for wet and dry matters was obtained in I100N400 treatment with values of 10.9 and 2.91 kg/m3, respectively.

Drought is considered one of the most important factors limiting crop performance worldwide. Consumption of humic acid on plants, in addition to soil fertility, increases plant tolerance to drought and soil water holding capacity. Chitosan is also a natural biopolymer modified from chitin and non-toxic, biodegradable, and environmentally friendly substances that acts as a potential stimulant in agriculture. Chitosan and humic acid reduce the negative effects of abiotic stresses. Accordingly, due to the drought crisis in arid and semi-arid regions, in this study, the modulating effect of humic acid and chitosan foliar application on wheat tolerance to drought stress at the end of the season was investigated.

This experiment was performed to study the effect of foliar application of chitosan and humic acid on improving drought tolerance of wheat genotypes in the form of split split plots based on a randomized complete block design with three replications. The main plot includes irrigation treatments at two levels (full irrigation and cessation of irrigation in spike stage), sub-plots including three wheat genotypes including Mihan, CD-93-9, and CD-93-10, and sub-plots including humic acid and chitosan foliar application levels (Zero, 2 g.L-1 of humic acid, 3 ml.L-1 of chitosan and the combination of humic acid and chitosan). The experiment was carried out on a field in Ardabil Agricultural Research Station. Sowing was done in October 2020 with a planting density of 450 seeds per square meter. Chemical fertilizer based on NPK soil test at 50, 100, and 20 kg.ha-1, respectively was added to the soil before planting. Each genotype was planted in 1.5 cm by 7 m plots. The length of each row was 7 m and the distance between the rows was 20 cm and the seeds were sown at a depth of 5 cm. STAR 2.01 statistical software was used to analyze the data including data analysis of variance and comparison of means by LSD method at a 5% probability level.

The results showed that the interaction effect of cultivar × stress × foliar application was significant in all studied traits including plant height, number of seeds per spike, number of spikes, spike length, and grain yield, except the number of tillers per plant and 1000-seed weight. Regarding the number of tillers per plant, the interaction of cultivar × foliar application was significant and for 1000-seed weight, the interaction of cultivar × stress and stress × foliar application was significant. Although there were differences in the response of wheat genotypes to the foliar application under both stress and non-stress conditions, in most traits such as number of tillers, number of seeds per spike, spike length, plant height, and 1000-seed weight, the best result was the simultaneous use of chitosan and humic acid. Was obtained. Also, both under non-stress and under stress conditions, the highest grain yield of the studied genotypes was obtained in simultaneous foliar application of chitosan and humic acid. In general, it can be concluded that the combination of chitosan and humic acid (2 g.L-1 humic acid and 3 ml.L-1 chitosan) significantly showed the best results in increasing the yield and yield components of wheat compared to the control treatment in both non-stress and the end of the season drought stress conditions.

Foliar application of humic acid and chitosan increased and improved the studied traits, both under drought stress and non-stress conditions in wheat genotypes compared to non-foliar application. The maximum number of tillers, number of seeds per spike, number of spikes, spike length, 1000-seed weight, and grain yield were obtained by foliar application of chitosan and humic acid under both full irrigation and stress conditions. Therefore, it is recommended to use simultaneous spraying of chitosan and humic acid to increase tolerance and achieve higher performance. Also, the study of different concentrations of these two substances in combination with each other and at different stages of wheat growth can determine the best dose and time of their consumption in this strategic crop, which is recommended to conduct studies in this regard.

This experiment was conducted in order to evaluate the effect of water deficit irrigation on the agronomic characteristics of fodder sorghum cultivars in Kerman province. This experiment was carried out as a strip split-plot in a complete randomized block design with four replications in a research farm of agricultural research center of Jirof and Kahnooj, Kerman province, in 2019 and 2020. Drought stress as a vertical factor in four levels including without stress (irrigation after 80 mm evaporation from evaporation pan) as control, mild stress (irrigation after 110 mm evaporation from the evaporation pan), medium (irrigation after 140 mm evaporation) and sever (irrigation after 180 mm evaporation) and four sorghum cultivars including Spidfeed, Sugar graze, Jumbo and Pegah as a horizontal factor. The highest yield of fresh forage yield under non-stressed conditions (control) was observed in Spidfeed and Pegah (121.60 and 118.79 ton.ha-1, respectively). Also, Spidfeed and Pegah had the highest dry forage yield under non-stressed conditions (control) as 22.50 and 20.69 ton.ha-1, respectively. Also, the highest yield of dry forage in mild drought stress was observed in Pegah and Speedfeed varieties (15.30 and 14.88 ton.ha-1, respectively) and under medium drought stress in Pegah (11.12 ton.ha-1), whereas Spidfeed variety was superior to others for dry forage yield (7.42 ton.ha-1), in severe drought stress. Based on MP and STI indices, Spidfeed and Pegah cultivars with higher average of dry fodder yield were selected as the most suitable genotypes under drought stress conditions in Jiroft region of Kerman province.

The level of aquifers has decreased as a result of the decrease in the water level of Urmia Lake in Iran. In addition, the infiltration of both salt water and excess salts, especially nitrates, caused by the use of chemical fertilizers have reduced the quality of groundwater in Urmia plain. Saline waste water, return water, agricultural activities, evaporation and infiltration of sea water are among the salinity factors of water resources. On the other hand, in modern agriculture, the yield and productivity of the product is improved by the use of chemical fertilizers. For this reason, agriculture is known as the most important source of non-point pollution of groundwater nitrates caused by human activities. The nitrate range of plain varies from 0 to 115 mg/l. Also, the level of EC varies from 0.3 to 2.9 ds/m. Both ranges are in warning points, which should be prevented from increasing excessively by adopting management measures. This study mainly aimed at investigating quantitative and qualitative changes of irrigation water in agro-economic terms. The present study was conducted in Urmia plain located in Urmia city of Iran. The area of the plain is 962 km2 and is located on the western side of the lake. The yields of irrigated wheat, forage corn, sunflower and tomato were simulated using the AquaCrop model in the cropping year of 2022-2023; then, the options of reduced irrigation, reduced fertilization and increased groundwater salinity were applied in all stages of crop growth. Also, four groups of climatic, crop, soil and management data were used for the simulation. In proportion to the fact that decreasing crop yield has economic effects, the effects were investigated by calculating water and nitrogen fertilizer physical and economic productivity indexes. Both consumption amount of each input per hectare and the purchase cost of each input were obtained through the interviews with 140 farmers using random classification sampling method. By adding all the costs, the cost of each product was calculated and the farmers' income was obtained according to the yield and price of the products. Then, changes in costs were examined by changing the amount of irrigation and fertilization. Changes in income were also calculated by applying each option, and net profit was obtained by changing the costs and revenues. By carrying out yield simulation and applying options, the impacts of yield reduction on farmers' productivity and profit were calculated and accordingly, the potential areas for growing each crop in each region were determined. Decreased fertilization demonstrated the utmost effect and increased salinity of irrigation water and groundwater revealed the least effect on the yield of crops. Among the two indexes, the economic productivity index of water IRI rials/m3 and fertilizer IRI rials/kg was chosen, based on which tomato (209580, 3005000) and sunflower (177630, 2115720) in region 5, forage corn (94900, 1323500) and irrigated wheat (5620, 454570) in regions 3 and 6 had the highest rate, respectively. Furthermore, the rate of fertilizer economic productivity index was higher than water productivity. After calculating these indicators, the value of the water and fertilizer economic productivity index was recalculated after applying the options and the changes were analyzed. With the reduction of irrigation, the water economic efficiency index for some crops decreased in some areas and increased in some other areas, but with the decrease in fertilization, the economic efficiency of fertilizer decreased in all areas and all crops. In both options, tomato and wheat had the highest and lowest amount, respectively.  Considering the obtained results and the quantitative and qualitative effects of water reduction in the region, it is necessary to reduce the effects of excessive use of chemical fertilizers before reaching a critical stage. In addition, reducing the excessive use of surface and underground water is vital. If the current trend continues, the cultivation pattern and the type of land use should be changed according to the conditions, or additional costs may be imposed on the farmers to eliminate the effects of excessive consumption, and all these cases require proper management of water resources to maintain their quantity and quality. Given the high impacts of the fertilizer reduction option and the economic productivity index of fertilizer, the possibility of replacing organic fertilizers with nitrate ones should be technically and economically investigated and the high price for using more than the recommended amount of nitrate fertilizers should be determined. These policies are also effective for reducing salinity because the main source of groundwater salinity is excessive fertilization. It is also suggested that appropriate irrigation technologies are introduced to the farmers and the correct cultivation patterns are presented in each region of the whole area. Finally, strict management actions should be taken to moderate the destructive effects of excessive fertilization and to reduce the over-exploitation of surface and groundwater.