نشریه مدیریت آب در کشاورزی
سال دهم شماره 2 (پیاپی 20، پاییز و زمستان 1402)

In the south of Iran, due to being located in the arid and semi-arid regions, the agricultural sector faces soil salinity resulting from the capillary rise of salt from the shallow saline water table to the soil surface and reducing crop yield. The objective of this research was to investigate the effect of surface drip irrigation (DI) and subsurface irrigation (SDI) methods on soil profile moisture and salinity distribution, maize (SC 703) yield, and irrigation water use efficiency in the presence of shallow saline water table (60 and 100 cm), during summer and spring seasons of 2021. A factorial experiment was conducted based on randomized complete block design with three replications in drained lysimeters filled with loamy soil (specific gravity 1.45 g cm-3) in field conditions. The results showed that the accumulation of salt above the dripper in subsurface irrigation method at both SDI100 and SDI60 treatments, was significantly more than the surface irrigation method (p<0.01). The results also revealed that summer maize yield was more than spring maize yield. Furthermore, in the summer season, irrigation in the root development zone in the SDI100 and SDI60 treatments caused an increase in the maize yield by 25 and 61%, respectively, and Water Productivity Index (WP) by 25 and 58%, respectively, in comparison to DI100 and DI60. Evaporation in SDI60 and SDI100 treatments was 26-30% and 43-51% lower than DI60 and DI100 treatments, respectively. The results of this research showed that SDI is more effective than DI in controlling soil profile salinity and plant yield.

Precipitation is considered one of the most important components of hydrological cycle, and its effective and usable amount for plants is of great importance in the agricultural sector, especially rainfed cultivation. In this research, the effective precipitation (EP) in dry wheat fields of Khomein city was estimated by using RS and SEBAL on 28 available images from Landsat8 in the crop years 2014 to 2022. Penman-Monteith-Fao method was used to evaluate the accuracy of SEBAL. Then, a model of EP estimation was developed with ANN and meteorological data. For this purpose, the correlation between meteorological data and Growin Degree Days (GDD) with EP was investigated by Pearson's correlation method. the meteorological data of three stations from the closest synoptic stations to the study area were used and The meteorological data of the study area were interpolated using the Inverse Distance Weighting method (IDW). According to the results of the correlations, the average temperature parameter with a correlation of 0.92 and the GDD and the maximum relative humidity respectively with a correlation of 0.86 and -0.77 as effective variables in estimating EP. In the next step, the most effective parameters were used for modeling. the networks were trained under different scenarios, and the performance of the networks was evaluated using the RMSE and MBE error criteria. The results showed that by using the BR learning algorithm and having the variables of daily temperature and GDD, it is possible to predict the amount of EP for the target area with very good accuracy. The RMSE value of this model was 0.1899 mm and MBE was estimated as -0.0115 mm. By using the presented model, with simple meteorological variables, the actual evapotranspiration and finally the EP of the desired area can be determined with appropriate accuracy without the need to solve complex algorithms.

Considering the climatic conditions of Yazd province and the need to cultivate low water-demanding and industrial medicinal plants, Guar plant was chosen to investigate the effect of drought stress and biochar as a soil conditioner. The experiment was carried out in the form of split split plots in a randomized complete block design with three replications. The main factor was three levels of drought stress I1, I2 and I3 (7, 10 and 14 days of irrigation cycle) and the first secondary factor was two commercial and local species and the second secondary factor was three levels of biochar (0, 0.5 and 1%). At the end of the experiment, the traits of gum percentage, ion leakage, relative leaf water content, chlorophyll a and b and chlorophyll index (SPAD) were measured. The results showed that the main effects of irrigation period on the traits of gum percentage, relative leaf water content, ion leakage, chlorophyll a and SPAD were significant at the five percent probability level. While the main effects of variety were statistically significant only on SPAD and also the main effects of biochar on ion leakage and SPAD. The interaction effect of irrigation period and variety was also significant only on the SPAD trait; Although the interaction effect of irrigation cycle and biochar on chlorophyll a and SPAD traits was significant. The interaction effect of variety and biochar,). In general, drought stress decreased the percentage of gum, the relative content of leaf water and significantly increased ion leakage. Also, the application of biochar caused a significant increase in ion leakage and SPAD, and a 10-day irrigation cycle with a level of 1% biochar in the native variety caused the highest amount of SPAD in the guar plant.

Water shortages today are exacerbated by the gap between supply and demand, resulting in misuse of underground water resources and declines in aquifer levels. In Fars province, the plain of Sarvostan is also one of the most critical areas when it comes to water resources. As a water consumption technology, volumetric water meters were proposed in a plan known as the aquifer recovery plan in order to manage water resources in this plain. This research was carried out with the aim of identifying the factors affecting participation in the aquifer recovery plan of Sarvostan plain, and in terms of the research method, it is descriptive-analytical. The statistical population of the research consisted of all the users of underground water resources in Kohnjan district of Sarvostan city (N = 1293), which was studied by stratified random method with proportional assignment of 384 farmers. The data collection tool was a researcher-made questionnaire, the face validity of which was confirmed by obtaining the opinion of panel of experts. The reliability of the measurement tool was also confirmed by conducting a pilot study and calculating Cronbach's alpha coefficient (0.90-0.68). Data were procossed and analyzed using SPSS statistical software version 25. According to the results of the logistics test, participation in the plan was largely determiened by trust, enjoyment, and the intention to participate. A comparison of the variables contributing to participation revealed that subjective norms, self-concept, attitude, intention, level of education, income, area under cultivation, ownership level, and irrigation interval were significantly deffierent from participation-averse stakeholders. In contrast to participation-averse stakeholders, participation-prone stakeholders had significantly lower average percieved cost, ages, children, and household size. Finally, to improve participation in the aquifer recovery plan, operational solutions were presented.

Considering the increased interest in zytonic as a soil amendment, we evaluated the calibration method using direct gravimetric and indirect time domain reflectometry (TDR) for soil moisture measurements to improve TDR measurement accuracy underused zytonic and different soil types conditions. Three soil textures: silty clay, sandy loam, and clay loam as well as two levels of zytonic: 0 (control), and 1 (Kg m-2 zytonic) were considered under greenhouse conditions. The drawing of the coherence chart between the results of the TDR method and the volumetric method values showed that the highest and the least coincidence between the two methods were observed in clay loam + used zytonic (1.0 Kg.m-2 zytonic) (R2=0.98) and silty clay + control treatment (R2=0.87). The results showed that the TDR method has high accuracy for measuring soil water content in clay loam soils. Regression analysis between TDR-Volumetric water content (ϴTDR) and weighing method (ϴv) showed a good correlation with an R2 of 0.92 (silty clay+ zytonic), 0.96 (sandy loam+zytonic), and 0.98 (clay loam+zytonic). The results showed that increasing zytonic in soils increased the accuracy of the device in all of the studied soil textures. These results confirm the necessity of using soil properties for soil sensors like the TDR for estimating soil water content in different soil environments and also suggest that TDR sensors may provide an opportunity to improve soil moisture measurements in higher-clay-content soils.

The purpose of this research was to investigate the sensitivity of reference evapotranspiration to meteorological variables and to introduce the most accurate database in providing these variables in the Urmia Lake basin. For this purpose, 24 synoptic stations were selected and their meteorological data was prepared on a daily basis between 2010 and 2019. Then, the reference evapotranspiration was calculated using the FAO-Penman-Monteith equation, and the effect of changes in meteorological variables on ET0 was investigated individually in the range of ±20%. In the next step, the accuracy of ERA5, CFSv2 and MERRA2 meteorological data was evaluated and the most accurate one was introduced. The ten-year average of reference evapotranspiration of the meteorological stations was obtained 3.1 mm d-1, and the results showed that the maximum temperature is the most influential meteorological variable on reference evapotranspiration changes. After that, wind speed and minimum temperature had the greatest effect, respectively. The value of sensitivity coefficient for maximum temperature, wind speed and minimum temperature was obtained 0.4, 0.2 and 0.1 respectively. In the review of meteorological data of ERA5, CFSv2 and MERRA2, statistical indicators showed that the ERA5 dataset has the most accuracy. Based on the results, the 10-year average of reference evapotranspiration of the ERA5 was obtained 2.86 mm d-1 and according to the CRM index, this value was 8% underestimated compared to the value obtained from meteorological stations. Finally, the values of EF indices equal to 0.92 and nRMSE equal to 0.17 put the reference evapotranspiration of the ERA5 in a suitable and reliable rank.

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.

The implementation of the Khuzestan Land reclamation Plan, has been provided a suitable platform to promoting research findings on the proper use of soil and water resources, agricultural inputs and increasing crop production. Therefore, this study was carried out in the agricultural year 2017-2018 with the aim of evaluating the water productivity resulting from improved management of canola production inputs and comparing it with conventional management in the northern lands of Khuzestan province. For this purpose, 11 farms (advanced management treatment) were selected to apply technical packages including irrigation scheduling, using the minimum tillage, applying balanced plant nutrition, raised bed planting, proper seed rate, according to farm conditions and farmer facilities. In each of these farms, the amount of applied water during the growing season, grain yield and water productivity were determined and compared with the surrounding farms data with traditional management (control treatment). The results showed that the average canola grain yield and water productivity increased from 2413 kg ha-1 and 0.51 kg m-3 in the control treatment to 2994 kg ha-1 and 0.69 kg m-3 in the superior treatment, respectively. This increase was statistically significant at the level of 1%.

Considering the importance of water consumption management in the agricultural sector, in this research, the application water efficiency and the water consumption volume in wheat fields of Semnan province were investigated. The volume of inflow, outflow, soil moisture before and after irrigation and the depth of root were measured and based on them, the values of application water efficiency was determined. The results showed that there is the most water losses in the first irrigation and the application water efficiency varies according to several factors such as farm management, depth, length and slope of furrows, physical properties of the soil. The average values of application water efficiency in the surface irrigation method were estimated at 30.6%. Inattention to the characteristics of the soil, the slope of the land, the depth and length of the furrows, the lack of proper leveling and inappropriate timing of irrigation with the plant's water requirements, and the low flow rate entering the furrows have caused an increase in water losses in the fields. The average volume of water consumption in Shahrood, Semnan, Damghan and Garmsar was 7700.7, 6628.3, 5875.4 and 7890.8 m3/ha, respectively. Comparing the calculated water requirement with the volume of irrigation water showed the application of deficit irrigation in the wheat fields of Semnan and Damghan. Also, the results showed that the calculated water requirement was higher than the values in the national water document. According to the area under wheat cultivation in the province, for every one percent increase in application irrigation efficiency, about 793,000 m3/ha of water will be saved.

Due to the water crisis, drought, population increase, and lack of conventional water resources, the use of new technologies to use unconventional water and manage consumption in different sectors is highly needed. In the present study, the factors affecting the success and failure of technological research in the water industry in Iran were analyzed with the aim of identifying the reasons for not applying of the country's water technological projects, inventions, and research. To provide effective solutions to strengthen the success and prevent the failure of water technologies, 15 questionnaires based on the Analytical Hierarchy Process (AHP) were completed by experts, experienced, knowledgeable, and proficient in the subject in the autumn and winter of 2022 and the results analyzed in the spring of 2023. According to the purpose of the study, the hierarchical structure included four technical, economic, social, and environmental criteria, each of which had four sub-criteria. After completing the questionnaires, the weights of criteria and sub-criteria were determined using Expert Choice software. To measure the accuracy of completed questionnaires, the inconsistency rate was calculated and equaled 0.09, which was less than the limit (0.1). The examination of the final weight of each of the sub-criteria showed that the first to third rank among all the investigated factors in the four main criteria, respectively, the ease of repair sub-criteria (S1) of the technical criteria with a final weight of 0.243, useful life (S4) from the technical criteria with a weight of 0.158 and the operation and maintenance cost (W4) from the economic criteria with a weight of 0.120. In general, the first two factors in the technical criteria and the superior factor in the economic criteria play a role as the most effective factors in the effectiveness of strengthening the success and preventing the failure of water technologies.

Considering that the surface irrigation system is one of the most widely used irrigation methods in the country, increasing the efficiency of this irrigation system is considered one of the country's main policies. In this research, by simulating surface irrigation flow using the method of solving Saint-Venant's equations (zero inertia method) in SIRMOD and WinSRFR software and comparing it with field observations in Ahvaz Sugarcane Research Center, the efficiency of the two softwares was investigated in the simulation of surface irrigation flow. Based on the analyzed statistical indicators, it was observed that in general, both softwares have a good ability to simulate the flow in furrow irrigation. Both models calculated the advance time and runoff more and the infiltration value less) than the measured values. In the investigation of furrow irrigation performance indicators, it was also found that the WinSRFR model simulation with higher application efficiency and lower runoff is closer to the measured data. Based on the results, the performance of WinSRFR software is better than SIRMOD software with a little difference (advance time 4%, infiltration volume 3% and runoff 6%). Also, it was observed that based on field experiments, the relative errors of inflow and infiltration water volumes were calculated by WinSRFR software 1.3, 2.7 and SIRMOD, 4.9% and 4.5%, respectively. In the estimation of runoff, the best and weakest performance was observed in the amount of 30.2 and 32.5 cubic meters, respectively, in WinSRFR and SIRMOD software

Considering the limitation of water resources and the need to increase water productivity in the production of agricultural products, the development of new irrigation systems has been one of the most important policies and activities of the agricultural water sector in recent decades. The purpose of this research is to quantitatively investigate the development of pressurized irrigation development in Iran and compare it with other countries and regions of the world using the pressurized irrigation development index, and finally the estimation of the optimal and expected level of its development for the country. According to the results, the PDI index until the end of the sixth development program (2020) is 21.4%, which is low compared to other 23 selected countries. Using the multivariable correlation method between the values of the variables affecting water management such as per capita withdrawal, the share of withdrawal from water resources in the agricultural sector, the area of irrigated lands, and the PDI index of 14 selected countries and applying values like for the Iran country, the desired and expected level of pressurized irrigation in the country was estimated at 49.2%. In other words, in the coming years it is possible to reduce the negative and undesirable effects of the unbalanced development of modern systems on water resources and the environment, and prevent the occurrence of the phenomenon of "rebound effect", in a favorable and potential way, up to half of the irrigated lands in the country should be equipped with pressurized irrigation systems. Meanwhile, according to the latest statistics, until the beginnings of 2023, the PDI has reached to 30% (2.9 million hectares). Therefore, there is still room for further development in terms of the necessary arrangements and under the condition of creating infrastructures, and necessary control rules and regulations by the related organizations.