سعید برومندنسب

Quinoa, a nutritionally rich crop with remarkable adaptability to unfavorable environments, exhibits a high tolerance to salinity. Reusing agricultural drainage water is a natural and important method in drainage management that increases farmers' income, sustainable production, and food security. The objective of this study was to investigate the effects of irrigation with agricultural drainage water, salinity stress, and water deficit on the yield and yield components of quinoa (Titicaca) under salinity levels of 2, 10, 15, and 20 dS/m and irrigation levels of full irrigation, 80%, and 60% of the crop water requirements. The experiment was conducted with three replications using a split-plot design with a randomized complete block design (RCBD) at the experimental farm of the Faculty of Water and Environmental Engineering at Shahid Chamran University of Ahvaz, during the fall and spring seasons of the years 2022 and 2023. The water requirement of Qinoa was determined gravimetrically by measuring soil moisture before each irrigation and increasing it to field capacity. The experimental treatments were imposed after seed germination and from the start of cultivation. The plants were harvested and transported to the laboratory for drying and yield component analysis upon physiological maturity. The results revealed that salinity stress had a more pronounced impact on reducing quinoa yield and yield components compared to water stress. The highest and lowest grain yields were observed in the autumn season, reaching 5.45 and 1.8 t/ha under the treatments of S1I1 and S4I3, respectively. Similarly, in the spring season, the highest and lowest grain yields were 3.87 and 0.73 t/ha under the same treatments, respectively.

Evaluation of drainage systems helps researchers and planners to examine the strengths and weaknesses of these systems and improve them in future plans. For this reason, in the present study, the performance of the drainage system implemented in the Gamboa irrigation and drainage network, located in the agricultural lands of Hamidieh city, was evaluated. In this research, she investigated the changes in water table level and salinity exit from the soil profile and measured the design indicators of underground drains. In order to read the water level fluctuations of the reservoir, observation wells were installed at intervals of 0.3, 0.8, 1.5, 2.5 and 15 meters and in the middle of the underground drains. The installation intervals of the observation wells between two drainage lines were 1/4L, 2/4L, 3/4L and 25 meters from the drain outlet. The results showed that The average hydraulic conductivity value in fields was 0.95 in reality and 0.89 m/day in design conditions, and the drainage coefficient value was 2.36 in reality and 2.6 mm/day in design conditions. Also, the examination of the proposed relationships for the design of the drainage system showed that Damm's relationship had the highest accuracy and Van Schilfgaard's relationship had the highest error in determining the water level. The control index of the depth of the ponding surface was between 0.82 and 1.11 and the control index of salinity exit from the soil was acceptable between -0.3 and -0.9. Product performance index was obtained in the range of (0.86-0.78). In total, after four years of the implementation of this drainage system, the productivity of wheat production increased by 62% from 2.55 tons per hectare to 4.1 tons per hectare compared to the conditions without drainage.

To determine optimal irrigation management and crop yield, the use of simulation models is an appropriate tool. AquaCrop is one of the practical models used for simulating yield variations under different water and soil management scenarios. This study investigates the interactive effects of salinity and water stress, as well as the utilization of drainage water irrigation, on the yield of quinoa and to simulate it using the AquaCrop model in an experimental field in the Faculty of Water and Environmental Engineering of Shahid Chamran University of Ahvaz in 2022-2023. This experiment was based on a system of split-plot experiment with a randomized, complete block design with three replications. The four salinity levels tested were 2, 10, 15, and 20 dS/m, and three irrigation regimes used were full irrigation, 80% of crop water requirement, and 60% of crop water requirement . The results indicated that the highest and lowest grain yields were 5.45 and 1.8 t/ha in autumn and 3.87 and 0.73 t/ha in spring, respectively, in treatments S1I1 and S4I3 .Various statistical analysis showed that the AquaCrop model had an acceptable accuracy in simulating quinoa yield, with NRMSE values less than 0.2 during the calibration phase. The statistical indices EF, R2, and d during the model validation phase (0.70, 0.88, and 0.97 in autumn and 0.74, 0.85, and 0.97 in spring) approached one, indicating adequate model accuracy in simulating grain yield. However, the model's accuracy in simulating grain yield during autumn in the validation phase with NRMSE, EF, R2, and d values of 0.18, 0.75, 0.74, and 0.83, respectively, was lower than its accuracy in simulating grain yield during spring seasons. Overall, the AquaCrop model exhibited acceptable accuracy in simulating quinoa yield under salinity and water stress conditions.

Potato is one of the most important food sources in the world and is considered one of the basic sources in different countries. Iran is the 13th producer of this product with the production of about five million tons of potatoes. The yield of potatoes is high compared to other crops, and for this reason, it has a higher water efficiency than other crops. However, potato yield is strongly dependent on the amount of irrigation water. This issue has caused special attention to be paid to the amount of irrigation water and many studies have been conducted on determining the optimal irrigation water. However, providing the right amount of irrigation water in each climate and irrigation system requires many experiments. These tests require spending a lot of time and money, which cannot be done in research centers in the current situation. To solve this problem, various plant models have been presented. The SALTMED model is such tool, accommodate different plants, soils, irrigation systems, irrigation management solutions, water qualities, and environmental stresses.

To carry out this research, the data collected from two research projects were conducted (the first project in 2012 and 2013, the second project in 2017 and 2018) in Shahrekord's research station. In the research projects, to manage irrigation in potato cultivation, two irrigation factors were investigated: the first factor includes different irrigation methods (S: drip, Su: subsurface drip, and F: furrow), and quantitative management of irrigation water as the second factor (FI: providing 100% of water needs, RDI80: providing 80% of water needs and RDI65: providing 65% of water needs) considering three repetitions. Data collected from the first year were used to calibrate the SALTMED model. The area of the plots was 40 m-2. Within each plot, four rows were planted with a row spacing of 75 cm and a seed spacing of 20 cm. The subplots were separated by one meter. In the surface drip irrigation method,  16mm drip pipes with an average flow rate of 1.75 L h-1 were used for each crop row. In subsurface drip irrigation, 16mm drip pipes with an average flow rate of 1.85 L h-1 were installed at a depth of 20 cm in the soil for each crop row. To evaluate the SALTMED model at this stage, the statistics of root mean square error (RMSE), normalized root mean square error (NRMSE), mean bias error (MBE), model efficiency (EF), agreement index (d), and determination of coefficient (R2) were used. Validation of this model was done using second-year data.

The highest and lowest differences between the observed and simulated values were 4.2 and 1.4 tons per hectare, respectively. The average difference between the observed and simulated values was 2.7 tons per hectare. The differences between the observed and simulated yields for drip, subsurface drip, and furrow irrigation methods were respectively 3, 1.9, and 3.1 tons per hectare. In addition, the accuracy of this model for simulating yield in the furrow irrigation method was lower than the other two methods. The highest and lowest difference between observed and simulated water productivity were 0.3 and 1.3 kg.m-3, respectively. The average of this difference was determined to be 0.7 kg.m-3. The difference between observed and simulated water productivity for drip irrigation, subsurface drip, and furrow irrigation methods was 0.8, 0.5, and 0.8, respectively. Based on the values of MBE statistics, the SALTMED model had an underestimation error in simulating yield and water productivity. The results of the NRMSE statistic showed that the accuracy of the SALTMED model for yield simulation was in the excellent category. The efficiency of the SALTMED model for yield simulation was acceptable based on two statistics EF and d. The R2 statistic for the simulation of potato yield by this plant model ranged from 0.88 to 0.99.

This research evaluated the SALTMED model for simulating potatoes' yield and water productivity under three irrigation methods furrow, drip, and subsurface drip. Using the recalibrated SALTMED model, a simulation of yield and water productivity was done to meet the water needs of 90, 55, and 45 % of potatoes for all three irrigation methods. A downward trend was observed between the reduction of water supply and potato yield in all three irrigation methods. The yield differences between the 100 and 90 %, and 90 and 80 % water supply in surface irrigation were 4.8 and 5.7 %, respectively. These values were respectively 18.6 and 8.7 % for drip irrigation and 13.3% and 1.7% for subsurface drip irrigation. Therefore, the slope of yield reduction until providing 80% of the water requirement was low in all three irrigation methods. The results showed that the SALTMED model had an underestimation error for simulating both parameters (MBE<0). However, the obtained error is negligible and the accuracy of this plant model was in the excellent category (NRMSE<0.1). Based on the results of EF (<0.88) and d (<0.99) statistics, the effectiveness of the SALTMED model was favorable for simulating both yield and water productivity. To determine the optimal amount of irrigation water, the recalibrated SALTMED model was used. The results showed that providing 80% of the potato's water requirement led to the achievement of an optimal yield and high water productivity.

This study was conducted with the aim of investigating the yield and yield components of Panicum millet plant under the conditions of combined stresses of salinity and deficit irrigation as a split plot experiment in a randomized complete block design with three replications and 48 treatments at the research farm, Faculty of Agriculture, Ilam University. Treatments included four levels of irrigation water salinity including 0.63, 3, 5 and 8 dS/m (S1, S2, S3 and S4 respectively) and four irrigation levels including 100, 80, 60 and 40 (w1, w2, w3 and w4 respectively) percentage of water requirement was done. The traits studied included leaf-to-stem weight ratio panicle length, plant height, shoot weight, thousand seed weight, seed yield and harvest index. The results showed that the applied salinity stress levels had a significant effect on harvest index traits, seed yield, thousand seed weight, shoot weight, panicle length and plant height at the 5% and there was no significant difference only on the leaf-to-stem weight ratio trait. The combined effect of salinity and deficit irrigation stress on all traits except for panicle length was significant at the 5%. Millet in the conditions of no stress (S1W1) and the highest level of stress (S4W4) applied in this study could yield 3.76 and 1.71 tons per hectare, respectively.

Based on this topic, the present study was conducted in order to evaluate the HYDRUS model in estimating the salinity and water table level of three farms in Gamboa irrigation and drainage network. This area is located in the agricultural lands of Hamidieh city.experiments were conducted in 2023 during three stages of irrigation in wheat farms, with area about 8 ha, in three fields with three lateral spacing 50, 75 and 80m. The results showed that HYDRUS had an underestimation error (MBE<0) in the estimation of two parameters, water table level and drain salinity, but the calculation error of both parameters was acceptable. In addition, the accuracy of the HYDRUS in simulating the water table level in all three farms was in the excellent category (0.0<NRMSE<0.1). The changes in the lateral distance had no effect on the HYDRUS error or accuracy. Failure to consider soil salinity at the beginning of the simulation caused the small error of estimating drain salinity in the first three days in all three farms. But at the end of the simulation, the salinity calculation error in all three farms was less than 7%. Also, when approaching the drainage outlet, due to the failure to consider the role of the collector in the HYDRUS, its accuracy decreased slightly compared to the beginning of the farm. However, considering the results, we can trust the accuracy of HYDRUS model in estimating the water table level and soil salinity in sugarcane farms.

In Iran, where there are 40 million acres of desert land, faces many challenges in combating desertification, the most significant of which is wind erosion. Afforestation is the easiest solution to deal with this phenomenon. Given the quantitative and qualitative limitations of water resources, selecting the appropriate irrigation method for rangeland plants is of great importance.In order to determine the most appropriate irrigation method for various rangeland plants, this study was conducted for two years (2019-2021) at Shahid Chamran University of Ahvaz. The experiment was conducted in a factorial design within a randomized complete blocks design with three replications.The main levels included four types of rangeland plants (Prosopis cineraria (T1), Conocarpus (T2), Albezia lebbek (T3), and Ziziphus (T4)), and the sub-levels included four types of irrigation (surface (I1), waterboxx (I2), pitcher (I3) ) and Bubbler (I4)).The results of the analysis of variance showed that the types of rangeland plants had a significant difference at the 1%  level in terms of measured indices (plant height, stem diameter, stem dry and wet weight, dry and fresh leaf weight, leaf area index, and water consumption volume, and water productivity). There was also a significant difference between irrigation methods at the 5% level  for all indices except stem diameter and leaf area index. Among the plant species, mesquite had the highest coverage (including height and dry and fresh weight), and the lowest amount of water consumption (averaging 996 liters per plant over two years), and the highest water productivity (9.72 kg/m3). Among the irrigation methods, the bubbler irrigation method had better coverage than other methods. In contrast, the waterbox irrigation method was superior in terms of water consumption and water productivity, saving 87% of water compared to surface irrigation and  increasing water productivity by 298%. Therefore, the waterboxx irrigation method can replace other irrigation methods in afforestation and desertification projects

The crop water stress index based on canopy–air temperature differences (CWSIdT) is an appropriate index for monitoring the water status of croplands but is rarely used to evaluate the water status of forest ecosystems. However, CWSIdT is rarely used in forest ecosystems. Investigating the possibility of using the crop water stress index (CWSI) for planning the irrigation of four species of pasture trees, Prosopis cineraria (T1), Conocarpus (T2), Albezia lebbek (T3) and Ziziphus (T4), under four methods of surface irrigation, bubbler, pitcher, and waterboxx system, was selected. This research was conducted in the year 2021 in the experimental farm of the Faculty of Water and Environmental Engineering of Shahid Chamran University of Ahvaz and lasted for 9 months. The experiment was conducted as a factorial in the form of a randomized complete block design with 3 replications. The crown temperature, actual evaporation and transpiration and meteorological factors of the field were continuously and simultaneously measured during the period from the beginning of April to the end of December. Infrared thermometers was used to measure crown temperature and vapor pressure deficiency values for different irrigation treatments. The results showed that under well-watered conditions, canopy-air temperature difference and canopy surface transpiration rate are both controlled by the net radiation received by the canopy surface The highest and lowest calculated CWSI values were related to waterboxx and Pitcher irrigation with values of 1.01 and 0.81, respectively, which were related to Ziziphus and Konocarpus trees. Statistical analysis showed that the effect of irrigation method on plant water stress index values in spring and autumn seasons was significant at the level of 5% and the average values of plant water stress index increased with water consumption reductions of 87 and 59% in waterbox and pitcher irrigation systems, respectively. However, there was no significant difference observed in the summer season. Also, the effect of tree type on the CWSIdT index during the period was important at a 1% level. In addition, the difference in vegetation and air temperature were used as a determining factor to determine irrigation time, which can be used to estimate pasture tree water stress.

Among the surface irrigation methods, furrow irrigation is the most common and adapted method to mechanization for agricultural system. Considering the lack of water resources and the problems that sugarcane cultivation and industries have faced in recent years, increasing the efficiency and productivity of the existing surface irrigation systems is of great importance. This study was conducted in order to investigate the effect of slope, furrow length and flow rate on sugarcane and sugar yield. For this purpose, an experiment was conducted in the form of split split plot in the form of randomized complete blocks with three replications in the Mirza kochak Khan Agricultural Company. This design was done with three treatments and each treatment at three levels including: 0.02, 0.04 and 0.06% slope, 150, 200 and 250 m length of the furrow and flow rate of 2, 2.5 and 3 lit/s. The yields of sugarcane and sugar in this study were 65.8 to 120.4 t/ha and 6.3 to 12.5 t/ha, respectively. The yield of sugarcane and sugar was significantly affected by the slope and length of furrow and flow rate. The average changes were significant due to the mutual effect of slope, furrow length and flow rate on sugarcane yield (P<0.01). 250 meters long, 2 lit/s flow rate and 0.04% slope with sugarcane yield of 120.4 t/ha and sugar yield of 12.6 t/ha, it is better for sugar production in the sugarcane fields of Mirza kochak Khan Agricultural Company. A combination of a 250 m long furrow with a slope of 0.04% and a flow rate of 2 lit/s can be recommended due to the reduction of deep infiltration losses and the reduction of water drainage and optimal water consumption, which has led to the production of sugarcane and sugar with appropriate performance.

To study the effect of green harvesting and preservation of plant residues on the soil surface, simultaneously with subsurface drip irrigation management, germination and tillering was tested in the first ratoon Sugarcane. This experiment was conducted at the number one research station of sugarcane cultivation and industry in Khuzestan. The experiment was carried out in the form of a statistical design of split plots. The treatments included the harvesting method and the depth of the driper installation. Harvesting methods in this experiment was green harvesting and burning harvesting. The treatment was to install drippers at three depths of 15, 25 and 35 cm. The results showed that the harvesting method and plant residues caused a significant decrease in sugarcane germination and tillering. So that plant residues caused a decrease of 48% in germination and 33.3% in tillering of sugarcane. No significant difference was observed in the depth of installation of dripers on sugarcane germination and tillering. interaction effect of the installation depth of the drippers and the harvesting method did not make a significant difference on sugarcane germination and tillering.

By using the temperature of the canopy cover of the plant, a practical parameter called the crop water stress index (CWSI), it was determined that this index is one of the methods of checking the water requirement of the plant and it can be considered as a suitable tool for irrigation management in the field. Therefore, this research was carried out with the aim of determining the water stress index of sugarcane in two methods of surface irrigation (CI) and subsurface drip irrigation (SDI) at research station number one of Khuzestan Research and Training Institute for Development of Sugarcane and Related Industries, in June 2022. The fields included the third field culture (Ratoon 3), of the CP69-1062 variety, and were selected with four repetitions in both methods. First, the equation of upper and lower base lines for the surface irrigation method was determined as (Tc-Ta)ul=1.7 and (Tc-Ta)=-0.09VPD+1.27, respectively. Then, using the equations of the lines based on the surface irrigation method, the average of crop water stress index for subsurface drip irrigation method and surface irrigation was calculated as 0.28 and 0.66, respectively, and the equation was presented according to the irrigation scheduling of the Sugarcane in June.

Water scarcity is the most important factor limiting the production of agricultural products, especially in arid and semi-arid regions. Application of some materials such as superabsorbent polymers in soil increases water retention in soil and thus reduces water consumption and fertilizer leaching. These materials can reduce the effects of dehydration on the plant and lead to increased yield in arid and semi-arid regions. In order to investigate the effect of superabsorbent under water stress conditions on yield, yield components and some physiological characteristics of corn, experimental plots were conducted in the form of split plots in a randomized complete block design in Gotvand region in Khuzestan province. Three treatments of Aquasorb 3005 (600,300,0 kg / ha) A1, A2 and A3 and four irrigation strategies (50,75,100,125) percent of water requirement I1, I2, I3 and I4 in three replications for two growing seasons, respectively Summer 2019 and spring planting 2020) were considered. Irrigation planning, biological yield, harvest index and canopy cover were measured at different stages of growth seasons, based on which a growth simulation model was presented using AquaCrop software. The results of this test showed that the use of Aquasorb 3005 increased product performance by one percent. In addition, the results show the effect of superabsorbent application and irrigation planning on improving water efficiency. The highest grain yield in spring and summer cultivation was related to I2A3 treatment equal to 9055 and 9255 kg / ha, respectively, and the lowest yield in both crops was related to I4A0 treatment equal to 5977 kg / ha in spring cultivation and 6344 kg / ha in summer cultivation.

Due to the increasing growth of population and changes in lifestyle, the pressure on water and soil resources has increased, thus, proper management of these resources has vital importance. This research was conducted with the aim of evaluating and comparing the effects of furrow, surface, and subsurface drip irrigation on water productivity, yield, and yield components of spinach in arid and semi-arid climatic conditions of Ahvaz. For this purpose, an experiment in the form of randomized complete blocks with three treatments of irrigation methods including furrow irrigation (FI), surface drip irrigation (SDI) and subsurface drip irrigation (SSDI) was done in three replications in the research farm of the Faculty of Water and Environmental Engineering, Shahid Chamran University, Ahvaz, in 2021. According to the results, the amount of irrigation water used in the FI treatment was 1066 m3/ha and in the SDI and SSDI it was 787 m3/ha, which showed a decrease of 26.17%. In FI, SDI, and SSDI, the average yield of spinach plant (total fresh weight of leaves and stems) was equal to 23.56, 30.17 and 19.28 g and irrigation water productivity was 0.353, 0.613 and 0.392 kg/m3, respectively. In both yield and irrigation water productivity, the SDI treatment had a significant advantage at 5% level compared to the other two treatments. The effects of irrigation treatment on the characteristics of root length, stem length, total length, number of leaves, number of fresh leaves, leaf chlorophyll content and harvest index were not significant. Generally, considering water productivity as criterion, surface drip irrigation is more suitable than furrow irrigation for spinach cultivation.

The purpose of this study was to investigate the effect of the depth of application and the discharge of drippers on the distribution of soil salinity in the sugarcane field under subsurface drip irrigation. This research was conducted as a split-plot experiment based on complete random blocks design in four replications. Experimental treatments including two dripper distances on the secondary pipe (including L1: 30 cm with a flow rate of 2.2 L h-1 and L2: 50 cm with a flow rate of 3.8 L h-1) and three dripper placement depths (Including D1: 15 cm, D2: 25 cm and D3: 35 cm). In order to investigate the effect of different treatments on salinity distribution in the soil, soil samples were collected four and six months after the start of subsurface drip irrigation, from the soil around the drippers at different intervals. The results of the salinity distribution pattern showed that under the conditions of subsurface drip irrigation, the highest salinity was observed in the bottom of the furrow and in the upper layer of the soil on the mound. Six months after the start of subsurface drip irrigation, the salinity of the soil profile in all treatments increased compared to the beggining, so that the salinity of the area around the drippers in most of the treatments reached above 3 dS m-1. The highest amount of salinity in the upper soil layers was observed in D3L2 treatment. Also, the most favorable salinity distribution pattern in the root development area was observed in D2L1 treatment. Therefore, it can be concluded that the use of drippers at a depth of 25 cm with intervals of 30 cm and a flow rate of 2.2 L h-1 is more suitable for managing soil salinity in the subsurface drip irrigation system.

Furrow irrigation is one of the most common and suitable methods of surface irrigation that is used in the fields of Mirzakochek Khan Sugarcane Company in the southwest of Khuzestan. Considering the problems that sugarcane companies have recently had due to the water resources scarcity, increasing the efficiency of surface irrigation systems with the aim of reducing water supply from Karun River is necessary. This study was conducted to investigate the effect of slope, furrow length and discharge on water application (Ea) and storage efficiencies (Es) as split-split plots and randomized complete blocks design with three replications from August 2018 to September 2019 in one of the farms of Mirza Kochakh Khan Company. This study was carried out with three treatments, each at three levels, including: slope of 0.02, 0.04 and 0.06%, length of 150, 200 and 250 meters and flow rate of 2, 2.5 and 3 l/s. Ea was obtained between 64.7% and 77.4% and Es between 65.2% and 100%. The highest Ea was corresponded to a slope of 0.04%, a flow rate of 2 l/s and a length of 250 meters. The highest Es was corresponded to the slopes of 0.04 and 0.06%, flow rate of 2 l/s and the length of 250 meters. Consequently, the slope of 0.04%, the flow rate of 2 l/s and the length of 250 meters are sujestted for furrow irrigation system of the sugarcane lands in the south of Ahvaz due to the optimal value of Ea and Es.

In recent years, the use of SWAT model has been used as a common tool for simulating flow rate, sediment production and evaluating different scenarios to reduce sediment production and runoff. The current research also aims to evaluate the changes in runoff and sediment under the influence of irrigation water reduction, using the SWAT model in the irrigation and drainage network of Dez River.

Recalibration and validation of the model for simulating runoff (Shoshtar, Arab Asad, Shavor Bridge, Harmeleh and Bamdej stations) and sedimentation (Shoshtar, Shavor Bridge, Harmaleh and Bamdezh stations) using statistical data from 1995 to 2012 and 2013 It was done until 2017. The simulation results were also evaluated using R2 and NSE coefficients. Then the scenarios of 10, 20 and 30% reduction of irrigation water were introduced to the model to evaluate their effect on runoff and sedimentation of the study area.

The results of model evaluation using R2 and NSE coefficients indicate the appropriate performance of the model in simulating the mentioned parameters. The results of the evaluation of scenarios of 10, 20 and 30 percent reduction of irrigation water show that applying the 10 percent scenario had the least impact on the amount of sedimentation. On the other hand, applying the scenario of 30% reduction of irrigation water will increase the runoff (30-60%) due to the reduction of the collection of runoffs for irrigation purposes and consequently the increase of the amount of sediment (20-50%) in the irrigation and drainage network of Dez River. The obtained results indicate that the increase in the amount of runoff in the basin, especially in the rainy season, has caused an increase in erosion and consequently an increase in sediment in the basin. Therefore, it can be stated that the time of applying the scenario and the characteristics of the soil in the area are the most effective components on the amount of runoff and sediment in the basin.

According to the results obtained, according to the effect of runoff on erosion and the amount of sediment in a watershed, it is necessary to use methods to control and reduce runoff, such as watershed operations, structures to contain and store runoff, and use modern irrigation methods to prevent soil erosion. Because traditional irrigation methods, in addition to water losses, cause a decrease in soil fertility and an increase in sediment in the drains of agricultural lands. In lands that are irrigated by traditional methods, sometimes the amount of water used is more than the infiltration capacity of the soil. This causes erosion of the surface layer of the soil by the runoff from water accumulation. Therefore, agricultural management approaches in basins prone to soil erosion should be focused on modern irrigation methods with minimum runoff and drainage output.

One of the important factors that reduce plant growth is the short-term water stress applied to the plant in the period of two irrigations. This research aims to investigate the relationship between crop water stress index (CWSI) of sugarcane and soil moisture under two systems of closed-end furrow irrigation (CI) and subsurface drip irrigation (SDI) at research station number one of sugarcane development research and training institute was done from July to September 2022. For this purpose, a field including ratoon 3, of the variety CP69-1062, with four replications for both irrigation systems was selected. First, the upper and lower baselines were determined for CI. Then, using these baselines, the average CWSI for SDI and CI systems was estimated for each month, separately. The highest value of CWSI for CI in September was 0.54 and for SDI in August was 0.49. Results showed that there is a high correlation between CSWI and soil moisture only in CI method for the depths of 0-30, 30-60 and 60-90 cm. The correlation between CWSI and soil moisture for CI was determined in the range of 0.60-0.70, and for SDI, in the range of 0.46-0.12. It seems that in addition to water stress, other stresses such as salinity stress caused by irrigation water and farm soil are also applied to the plant.

In order to investigate the effects of deficit irrigation and organic mulch on wet matter, dry matter, plant height, wet yield productivity, dry yield productivity and leaf area of corn forage (SC. 704) in Khorramabad region, an experiment based on the factorial experiment with a basic design of randomized complete blocks with three replications was conducted. The first factor of the experiment consisted of four levels of irrigation (100, 80, 60 and 40% of water requirements) and the second factor included three levels of organic mulch (no mulch (control), using 7.5 ton/hectare and 15 ton/hectare mulch). In this research, drip irrigation system (Tape) was applied and class A evaporation pan was used to determine the water requirement of the plant. The results showed that the mutual effects of deficit irrigation and organic mulch were significant at the 5% probability level. The maximum amount of wet matter (99.05 ton/ha), dry matter (31.15 ton/ha), plant height (2.38 m) and leaf area (7511cm2) were observed in the treatment of 100% water requirement and using mulch (15 ton/ha) which increased by 24.7%, 18.03%, 5.8% and 48.38% respectively compared to the control treatment. The maximum amount of water productivity for wet and dry matters were 14.56 and 4.57 kg/m3 which were obtained in the treatment of 80% water requirement and using mulch (15 ton/ha). The minimum amount of water productivity for wet and dry matters were 10.09 and 3.35 kg/m3 which were obtained in the treatment of 100% water requirement without using mulch.  Thus, in this region, irrigation based on 80% water requirement and using mulch (15 ton/ha) may cause improvement in corn forage yield.

Aloe vera L. is one of the medicinal and perennial plants, which is cultivated in arid and semi-arid regions. Although this plant is relatively resistant to lack of irrigation, but in the conditions of commercial cultivation, it is necessary to pay attention to the supply of irrigation water during the growing season. Due to that, the present study was conducted in order to investigate the effect of the amount of irrigation water (I1: 50, I2: 75 and I3: 100% of water requirement) and Trava 2020 superabsorbent (A1: zero, A2: 5 and A3: 10 grams per kilogram soil) on the yield and yield components of Aloe vera. These treatments were applied in three replications and the crop was harvested in two times include: autumn 2020 and spring 20201. The experiment was carried out in a research farm in Omidiye city with longitude 30°37’ and latitude 49°49’. Leaf length, leaf width, leaf weight, number of leaves and number of offset in the second harvest were 26.8%, 25.1%, 25.5%, 27.0%, 24.1% and 17.5% more than the first harvest. Increasing the consumption of superabsorbent caused an increase in leaf length. The difference between the leaf length in two treatments A3 and A2 was about 3.4% and between two treatments A3 and A1 was about 6.9%. With the increase of superabsorbent consumption, the leaf width increased so that its value reached from 79 mm in A1 treatment to 83 mm in A3 treatment.

From the economic and medicinal point of view, Aloe vera is a herbaceous and perennial plant that has attracted the attention of many farmers Iran. Climatic conditions throughout the year and the quantity and quality of irrigation water affect Aloe vera yield. For this reason, the research was conducted with the aim of investigating the effect of aforementioned factors on the Aloe vera yield and yield components. To achieve this goal, a strip-block design was carried with two factors, include: amount of irrigation water at three levels (I1: 50, I2: 75 and I3: 100% of irrigation water requirement) and irrigation water salinity at two levels (S1: 5 and S2: 10 dS.m-1) with three replications, in a research farm in Omidiye with longitude 30°37° and latitude 49°49°. The first harvest was done in the fall of 2019 and the second harvest in the spring of 2020. The results showed that in the first harvest, irrigation had a significant effects on leaf width, leaf fresh weight (P-value≤0.05), gel weight, the ratio of gel weight to leaf weight, the number of leaves and the water use efficiency (P- value≤0.01). Salinity had a significant effects on leaf thickness (P-value≤0.05), leaf width, leaf fresh weight, gel weight, the ratio of gel weight to leaf weight and water use efficiency (P-value≤ 0.01). In the second harvest, irrigation had a significant effects on the ratio of gel weight to leaf weight, number of leaves and water use efficiency and salinity had a significant effects on leaf width, leaf thickness, leaf fresh weight, gel weight , the ratio of gel weight to leaf weight and water use efficiency . In both the first and second harvests, the interaction effect of irrigation water and salinity only showed a significant effect on the water use efficiency (P-value ≤ 0.05).

Population of the world is growing day by day, this will create a situation in which that the water natural resources is becoming limited. According to the classification of the International water Management Institute (IWMI), Iran is one of those countries which by the year 2025 will face a deep major water deficit.There fore, it is clear for us that we must keep in our mind, to use the water natural resources in the best possible manner. Sugarcane is one of the major crops of the tropical and semitropical climatical areas which it has been cultivated in the province of Khouzestan since the ancient times. high share of water use efficiency specially during the warm season growth in this area. The irrigation system for sugarcane crop in this study was the furrow irrigation system. This research project was conducted to varity the effectiveness of the shape furrow irrigation method for the application efficiency of the sugarcane plantations in the province of Khouzestan and the Karun Agro-Industry, Inc with three different treatment depths of 30 Cm, 22 Cm, and 16 Cm respectively, and with three replications to study the above mentioned subject. The three different above mentioned treatments had been shown by the letters A,B,C .For making these furrows for treatments A,B we had used bulldozer (with rotary chain – D6 Model) ; and for making furrows for treatment C, we had used tractor (with high flatation tire – John Deer Model) with a furrower which its’ wings had been modified.

in order to determine the economic evaluation of Grain Maize crop behavior in relation to Surge and alternate Deficit irrigation strategy, a research in Jaydar plain of Poldokhtar city during the year 2021-2022 was done. The statistical design of the research was Factorial design in a randomized complete block design Which has two factors at 5 and 3levels. Factor A (five furrow irrigation methods) including conventional irrigation (C), Surge irrigation with one-to-one flow wave cycle ratio until advance time is complete (S_1), Surge irrigation with two-to-one flow wave cycle ratio until advance time is complete (S_2) , fixed alternate irrigation (FF) and variable alternate irrigation (AF) as well as factor B (three irrigation regimes) including 100% water requirement (I_100), 80% water requirement (I_80) and 60% water requirement (I_60). The number of experimental treatments was 15 and the number of replications was 3 replications. The results showed that in irrigation methods, the highest gross and net profit in relation to the amount of water consumed is related to the s_1 surge irrigation method respectively with values of 20.24 and 9.87 thousand Rials per cubic meter. In different irrigation regimes, the highest gross and net profit in relation to the amount of water consumed respectively is related to the (I_80) with the amount of 19.46 thousand Rials per cubic meter and (I_100) with the amount of 8.29 thousand Rials per cubic meter was determined. Finally for different irrigation treatments, the highest gross and net profit in relation to the amount of water used was related to the treatment S_1 I_60 respectively is 22.53 and 10.7 thousand Rials per cubic meter.

Sensitivity analysis is one of the steps in preparing a crop model before calibration, which helps researchers to find more information about the effects of each parameter on the results to increase the accuracy of the model in the calibration stage. Because of the capabilities of AquaCrop, researchers use it to simulate crop growth in different irrigation managements. The present study was conducted to analyze the sensitivity of AquaCrop in simulation of potato biomass to changes in crop growth parameters includes normalized water productivity (WP*), maximum transpiration coefficient (KCTrx), initial canopy cover (CC0), canopy growth coefficient. (CGC) and canopy reduction coefficient (CDC) using Baven (1979) method. Data were collected from a research farm in the Chahartakhteh area of Shahrekord, Iran, during two years. These data included the effect of two factor includes: irrigation method (surface and subsurface drip irrigation) and different irrigation levels (FI: 100% water supply, RDI80: 80% water supply and RDI65: 65% water supply). The results showed that the model AquaCrop had the highest sensitivity to WP* and the lowest sensitivity to CCo and CDC. The trend of potato biomass changes was inverse for CDC and direct to other parameters. Increased water stress in WP* and KCTrx parameters decreased the sensitivity of AquaCrop model. Therefore, in order to calibrate the AquaCrop in the conditions of a large difference between the simulated and observed values, it is better to change WP*. Otherwise, it is suggested to change the other parameters.

The objective of this study was to investigate the effects of combined stresses of irrigation salinity and nitrogen fertilizer on the yield and yield components of millet plant. The field experiment was conducted as a split plot experiment in a randomized complete block design with three replications at the research farm, Faculty of Agriculture, Ilam University during growing season in 2022. Treatments included four levels of irrigation salinity including 0.63, 3, 5, and 8 dS/m (S1, S2, S3 and S4) as main plots and three nitrogen fertilizer levels including; 100, 75 and 50 % of fertilizer requirement (N1, N2 and N3) as subplots. The results showed that the effect of salinity stress was significant on leaf/stem ratio and panicle length at P<5% and for the rest of the yield components at P<1%. Also, the effect of different nitrogen treatments was significant on all components yield of millet, except leaf/stem ratio, panicle length and plant height. The interaction effect of salinity and nitrogen stress was significant on thousand seed weight, biomass weight, yield and harvest index at the at P<1% and had no significant on leaf/stem ratio, panicle length and plant height. The highest millet yield was 3.76 tons per hectare in S1N1 treatment and the lowest yield was 2.53 tons per hectare in S4N1 treatment.

Drip tape irrigation, if designed and implemented correctly, is an effective way to increase irrigation efficiency. The present research was conducted in order to investigate the effects of plastic mulch and discharge on the soil wetting pattern dimensions and water retention from a linear source. For this purpose, an experiment in the statistical design form of random complete blocks with four treatments including two factors of application or non-application of plastic mulch and discharge (2 and 4 liters per hour) was designed in three replications. This research was carried out in farm of the Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, in a soil with silty clay loam texture. The soil wetting pattern dimensions, 24 hours after the end of irrigation were determined. The soil moisture difference between the second and fourth days after irrigation was considered as a measure of soil water retention. The soil moisture was determined after 24 and 72 hours from the end of irrigation. According to the results, with the application of the mulch, the depth, width and wetted area of the soil increased by 13.59, 20.25 and 38.54 %, respectively, compared to the non-mulched treatments, which was significant. The soil moisture difference between the second and fourth days after irrigation decreased from 1.96% in the non-mulched borders to 0.65% in the mulched borders. With the increase of discharge from 2 to 4 liters per hour, the soil wetted depth decreased from 27.22 to 23.55 cm, the soil wetted width increased from 26.72 to 31.88 cm, and the soil wetted area increased from 602.17 to 658.28 cm2, which indicates significant effect of increasing discharge on these parameters in all cases. The increase in discharge increased soil water retention, but this effect was not significant. The application of mulch has a greater effect on increasing the soil wetting pattern dimensions and water retention than the increase in discharge. Therefore, the use of plastic mulch is recommended to increase the efficiency of the drip irrigation system.