مجله آبیاری و زهکشی ایران
سال هجدهم شماره 5 (آذر و دی 1403)

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.

Due to the occurrence of drought in the last decade and its intensification in recent years in Iran and consequently in the Zayandeh Rood River Basin, the sustainability of water resources has faced a serious challenge. In this regard, the sustainability of water resources will be realized with institutions appropriate to the conditions of the area and participating stakeholders. In order to reach this situation, it is necessary to know and examine the governance regime in the country's watersheds. For this reason, in this research, the mode and regime of governance in the Zayandeh Rood River Basin, which is a common strategic water resource in the country, is investigated and determined. To determine the governance method at the organizational level, a questionnaire with acceptable validity was used by the relevant professors and Cronbach's alpha coefficient was 0.78. n order to analyze the results of the questionnaire to determine the governance style at the organizational level, the answers were entered into SPSS software and then analyzed using the Friedman, Duncan and analysis of variance tests. The results showed that out of ten sub-functions of governance, nine functions have a hierarchical mode of governance, while four functions have a network mode of governance and only one function has a market mode of governance. Also, in order to determine the governance regime in the Zayandeh Rood River Basin, the Social network analysis method (SNA) was used. The results of the analysis of the institutional network also showed that the current governance regime in the Zayandeh Rood watershed is a centralized rent-seeking regime, which is considered one of the characteristics of the hierarchical governance style. Finally, in order to achieve Polycenteric governance, it was proposed to transfer decisions to the sub-basin and integrate governance methods.

Timely and accurate crop yield estimation is important to regulate crop management and ensure agricultural sustainability. This research investigates the application of the support vector regression method in simulating the yield of barley in ten selected farms in the Qazvin plain from 2019 to 2020 using the drought indices NDVI, MSAVI, and EVI. Sentinel 2 satellite was used for drought indices. The results were evaluated using R2, RMSE, and ME statistics. To investigate the application of the support vector regression method in simulating the yield of barley using the mentioned drought indicators, seven scenarios were defined. The results of evaluating the relationship between NDVI, MSAVI, and EVI indices with yield barley showed that the support vector regression method in all scenarios except the first scenario in the test phase with a significant probability of 95% (P-value=0.0) and an explanatory coefficient of more than 0.7 and the low value of the RMSE index has a good estimate of the yield of the barley product. The results of this research will be useful in managing and planning the development of barley cultivation based on drought indices in the future.

The main purpose of this research is to identify and prioritize the technical, social and economical problems of localized irrigation systems in the cities of Qom province. Each of these problems has several variables and these variables are also made up of different characteristics. recognizing the existing challenges and evaluating and monitoring of problems, will be improve water productivity in the country. The research question was investigated in the form of a questionnaire among farmers. The common feature of all these farmers was the implementation and use of drip irrigation. The questionnaire was distributed to the farmers who had implemented the localized irrigation system. This measurement tool was used after the validity and reliability and sample size estimation in the data collection, and finally the data was analyzed using hierarchical component models by partial least squares (PLS) method. Cronbach's alpha coefficient was used to measure reliability. The t test was used to check the significance of the relationship between variables. The results showed that the technical with an alpha value of 0.81 has good reliability. The results of the evaluation showed that the technical aspect with an alpha value of 0.81 has adequate reliability in the answer and the farmers are unanimous in expressing their opinion. The economical and social aspects also have acceptable reliability with an alpha value between 0.5-0.75. In general, the results of the research showed that the main problems of the implemented systems in Qom province are caused by technical, economical and social aspects, respectively.

Iran is one of the dry regions of the world and is currently facing a severe water crisis.Therefore, more attention should be paid to the optimal use of water and the protection of water resources.which is very important in providing food for the residents of our country. Also, planting time is one of the most important dates in the agricultural calendar of a plant, because other agricultural activities are determined accordingly.One of the newest models that has the ability to simulate the rate of growth and performance of various agricultural and horticultural crops in relation to the amount of water consumed is called the Aquacrop model. The purpose of this research is to simulate and determine the most appropriate date for planting Sirvan blue wheat in South Khorasan province using the AquaCrop plant simulator model.For this purpose, daily climate data as well as other environmental information from Birjand synoptic station have been used in a two-year period(1395-1396)and(1396-1397)and the efficiency of the model has been evaluated using field data. After ensuring the effectiveness of the model, 3 treatments with 3 irrigation levels of 75, 100 and 125% of water supply, with two levels of salinity(6 and 1.6 dS/m)were simulated on the planting dates of November 1st to December 10th. Among the input dates to the model, the date with the highest yield was selected as the best planting date for the study area.The results of the research showed that the suitable planting date is different for each climate, and on the other hand, the yield of wheat is very sensitive to the characteristics of each region in choosing the type of variety and changing the planting date.Therefore, in this research, the best planting date of Sirvan wheat cultivar for the studied area was the second half of November, which is recommended.

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.

Water and soil salinity has a negative effect on the growth and development of plants. In order to investigate the effect of humic acid on the improvement of vegetative and physiological traits of wax-leaf privet (Ligustrum japonicum) plants under salt stress, a completely randomized factorial design experiment was carried out. The first factor was sodium chloride (0, 60, 120 and 180 mM) and the second factor was humic acid (0, 500 and 1000 mg/l). According to the obtained results, the maximum branch length, leaf length and width and the number of new leaves were obtained in humic acid 1000 mg/l without salt. At 180 mM salinity without humic acid pretreatment, the mentioned traits had a significant decrease. The highest fresh and dry weight of the root was obtained in 500 and 1000 mg/l of humic acid without salt, respectively. Maximum carotenoids and phenols were recorded in humic acid treatment of 500 mg/l under 60 mM salinity. The highest amount of accumulation of sodium and chlorine elements was in plants that were under 180 mM salinity without humic acid treatment. According to the results, the application of humic acid is recommended in order to reduce the negative effects of irrigation water salinity in the wax-leaf privet.

The present research was performed with the aim of investigating the efficiency and productivity of water and fertilizer in guar cultivation and analyzing the profit obtained from it, under different levels of nitrogen and plant density in Taibad city of Khorasan Razavi Province. The experiment was performed as a split plot in the form of a randomized complete block design with two factors and in three replications. The first factor included nitrogen fertilizer, based on the recommendations of soil laboratory, at three levels without giving nitrogen fertilizer (zero kg per hectare of urea) and 50 and 100% of guar's need for nitrogen (equivalent to 150 and 300 kg per hectare of urea, respectively), that was applied half of it at the time of planting and other half at the time of podding stage of guar. The second factor also included three levels of guar plant density, which was implemented as densities of 20, 33 and 66 plants per square meter. The results indicated that the highest use efficiency and productivity of fertilizer was obtained in condition of no nitrogen consumption and at a density of 66 plants per square meter. However, the highest seed yield and water use efficiency and water productivity, as well as the highest net profit, were obtained in condition of supplying 100% of guar nitrogen fertilizer requirement (300 kg of urea per hectare) and in two densities of 33 and 66 plants per square meter, the increase in plant density from 33 to 66 plants per square meter did not have a significant effect on improving seed yield and increasing the net profit of guar cultivation. Nevertheless, in conditions of not fully supplying the plant's nitrogen needs, increasing plant density was able to neutralize the effect of nitrogen deficiency and increase yield and net profit significantly.

The purpose of this research is to investigate the effect of nitrogen fertilizer and different irrigation levels on crop yield per unit area, water use efficiency (WUE) and economic land productivity (ELP) on potato crop in the South Karman-Jiroft Agricultural Research Center. In this research, irrigation level treatments in three levels including 100% full irrigation (WL1), 90% irrigation (WL2) and WL3 irrigation 80% and three levels of complete fertilizer 100% fertilizer (F1), 60% fertilizer (F2) and 40% fertilizer (F3) were investigated, and the investigated variables include crop yield, WUE and ELP. The results of this research showed that there is no significant difference between WL1 and WL2, but there is a significant difference between these two levels with WL3. This means that reducing the level of irrigation up to 100% compared to full irrigation will not have a significant difference on the crop yield and ELP. Therefore, the optimal level for the WUE, crop irrigation is 90%. Examining the simple effect of fertilizer levels also showed that there is a significant difference in the crop yield and WUE between F1 and F3, these two levels do not have a significant difference with F2, but there is a significant difference in the land value between F2 and the other two levels. Therefore, the 100% fertilizer level has the highest crop yield and ELP, which shows a significant difference with other levels. Finally, by examining the two-level effect of treatments at different levels, the results showed that the optimal level of fertilizer and irrigation, which has the highest ELP, crop yield and WUE, is WL2F1. Therefore, in this area, according to the existing conditions, this treatment is suggested.

Bridges are important for establishing communication routes, and every year many bridges are destroyed due to scouring around the support. Spur dike are hydraulic structures that reduce scouring by diverting streamlines from structures. In this paper, a triangular arrangement for permeable spur dikes is proposed, and its performance with linear spur dikes in controlling the scouring of the abutment is numerically investigated and compared. To make a correct comparison, the permeability ratio and the distance of both triangular and linear arrangements were assumed to be the same. The results show that the linear arrangement of three series of two columns performs better than the similar triangular arrangement, and the linear arrangement of four and five series of two columns performs worse than the similar triangular arrangement. Also, among all the models, the triangular arrangement equivalent to two series of five is the most optimal. It reduces scour depth by 46% compared to the control case (Abutment without protective spur dike).

Estimating the amount of irrigation water and assessing water productivity in gardens is particularly critical in the context of current drought conditions and water scarcity. This article examines the cultivation of walnut and almond trees from the perspective of water consumption. The study was conducted in Koran Village, located in the Esfandegheh area of Kerman Province. The permanent Gishki River serves as the source of water for surface irrigation in this region. Water is transferred from the river to storage pools and irrigation canals through a network of channels managed by local operators. The reference crop evapotranspiration was calculated using the Hargreaves-Samani equation, while irrigation water consumption was determined based on the volume of water stored in the pools and the area of the gardens. Consequently, the study assessed the implications of excess or deficit irrigation in relation to farmers' water management practices. The water productivity in the current irrigation conditions of the region was calculated for almond and walnut trees as 0.6 and 0.27 kg/m3, respectively. Water productivity in water shortage conditions for almond and walnut trees was determined to be 14% higher and 10% lower than in sufficient water conditions, respectively. Additionally, Ky of almond was 47% lower than walnut. Also, the economic water productivity achieved for almond trees is 1.8 times that of walnuts. The findings indicate that the cultivation of almond trees is more advantageous than that of walnut trees in the Esfandegheh region, particularly in terms of water consumption and economic efficiency, especially under conditions of water scarcity.

Severe and sudden floods have always led to irreparable damages, including the deaths of thousands and significant economic losses. Rapid flood zoning is one of the most important and fundamental aspects of crisis management and reducing flood-related damages. To mitigate risks, damages, and take timely action, it is essential to quickly identify areas prone to flooding and inundation and take necessary measures. In this study, a new user-friendly module of STE software was developed to solve shallow water equations more rapidly. By introducing and examining new grid discretization and subgrid variability methods, the process of flood zoning and simulation has been accelerated. To evaluate the proposed methods, flood modeling was conducted for the flooding event caused by Hurricane Harvey in 2017 in the vicinity of Hempstead city, Texas, USA, along a 22-kilometer stretch of the Brazos River. The comparison of results obtained from accurate and long-term flood modeling using shallow water equations with the rapid methods presented in the study demonstrates that subgrid variability methods can significantly reduce the modeling time for flood simulation from 1090 minutes to 17 to 36 minutes (a 97% reduction) while maintaining modeling accuracy. This is achieved with a flood zone accuracy of 94% and a root mean square error (RMSE) of 0.14 for flow depth modeling.