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This research was used from climate information such as average humidity, average wind speed, soil temperature and salinity of different soil depths (5, 10, 20, 30, 50, and 100 centimeters) in 10 years (2008-2017). The purpose of this study was to investigate the relationship between climate parameters and soil salinity fluctuations. For this purpose, rice soil salinity data were used which were previously measured. In both seasons of rice cultivation (conducted in one of the nurseries of Alborz province), salinity fluctuations at different depths of soil were recorded over a period of five to seven days, and soil salinity required for the purposes of this study was obtained, and then with the required meteorological data, the research was done. Also, Hurst test to find enough variance of the data to analyze the time series trend, and Mann-Kendal, spearman, and multivariate regression tests were applied for data analysis. The results showed that all parameters of the study based on the Hurst coefficient bigger than 0.5, had a significant variance for time series analysis. The results of Mann-Kendal and spearman tests showed that in surface soil layers (5 and 10 cm) after 10 years period, the soil salinity had a descending trend. However, both tests had an increasing trend in deeper layers (20, 30, 50 and 100 cm) and at depths of 50 and 100 cm observed the significantly increasing trend at a 5% level. Result of the multivariate regression test illustrated that the temperature in depth of 5 cm and average relative humidity (each 16%) and average speed of 60% had the most and the least effect, respectively on the soil salinity in the mentioned soil depth. Also, in four depths of six depths, the temperature in depth of 5 cm was the most effect on soil salinity of different soil depths. As a general result, in areas where the conditions of this present study, cultivation of plants with surface roots is possible because salinity fluctuations in the surface layers are low and it does not pose a threat to the plant under cultivation but crop cultivation with deep roots is limited because salinity fluctuations is an increasing trend that should be addressed so that soil salinity does not have a detrimental effect on plant yield.

Due to the issue of water scarcity and drought in Iran, agriculture water management is essential. Agriculture water management requires a policy of correct and efficient use of water, and the smart irrigation system is a suitable and optimal way to use water properly. For this purpose, a moisture sensor device was designed and constructed in February and March 2019 to determine the appropriate time to stop irrigation in furrow irrigation. Testing the device in the laboratory and its application in the Farm of the Campus of Agriculture and Natural Resources, University of Tehran, (Mohammad Shahr), Iran, from April to July 2019. The purpose of this study was to evaluate the performance of smart sensor of soil moisture to determine the optimum depth of installation and recording of soil moisture at 10, 30 and 50 cm depths and different length ratios in furrow irrigation. Initially, calibration of the device was carried out on field soil and based on the obtained validation, the device was transferred to the field. To achieve the goals of optimum depth of installation and optimum length, 36-meter furrows with a distance of 0.75 meters were created in the field. Sensitive lengths in furrows with 0.5L, 0.75L, and 0.85L ratios were selected as the starting points. The results showed that in the calibration and validation phase the R2 value (coefficient of determination) were 0.93 and 0.95, respectively, and in the calibration and validation stage the value of NRMSE (Normal Root Mean Square Error) was 80 and 13.81%, that indicating good model training in the calibration stage. Also, the average RE (Relative Error) parameter in estimating soil moisture was 2.74%, indicating high accuracy of the device in estimating soil moisture. The results also showed that if the device was installed at a depth of 30 cm from the soil surface of the furrow and at 75% from the beginning of the field, the depth and runoff losses would be minimal and irrigation adequacy would be best compared to other depths and lengths. It is expected that with optimal water consumption and timely interruption of irrigation, deep losses and runoff will be avoided and with low water consumption, the productivity of crops will increase.

Groundwater resources play an essential role in water supply for drink, griculture, and industry sectors. Nowadays, for various reasons, such as urban and opulation growth, indiscriminate use of fertilizers and chemical poisons, groundwater resources have been populated. Therefore, studying the pollutions and their fate and preventing groundwater resources from the pollutants is necessary. In this research study, a laboratory physical model has been designed and performed in order to obtain enough data of pollution movement in homogeneous porous media. In other words, the main aim of this paper is to track the distribution of a conservative tracer in porous media in a laboratory-scale model to estimate the longitudinal and transverse dispersion coefficients. In this study, non-cohesive sands were used to create the porous media body in the laboratory model, and the grain diameter of the sand was 1-2.5 mm. Salt with concentrations of 5, 7.5, and 10 gr/l was used as a tracer. The porosity of the sand was measured equal to 39\%, and the hydraulic conductivity of that was measured equal to 172.26 cm/hr using the constant load test. In order to control changes of flow velocity, to minimize test errors, a constant head of water was created over the entrance of the sand body. The flow velocity was measured equal to 1.21 mm/sec. An EC-meter apparatus was used to measure the EC values of the tracer inside model; then, these data were used to calculate the concentration of tracer in different points over time, during each test. Then, the values of the concentration were compared with those of concentration which were obtained from the analytical solution of Fick's second law. Root Mean Square Error criterion (RMSE) was used to compare the measured and calculated mentioned data. According to the results, the values of the longitudinal coefficient tracer for the studied conditions, concentrations of 5, 7.5, and 10 gr/l, obtained 3.36e-6, 3.08e-6, and 3.52e-6 for transverse coefficients 6.58e-7, 6.49e-7, and 6.79e-7 m2/s, respectively.

Hydraulic conditions and identification of reach based on which maximum shear stress occurs are very complex problems in river bends. In this research, a method is developed for determining the location of this reach in bends. In addition, results of this method are compared to instructions of report No. 592 (prepared by Iranian Ministry of Energy). Downstream of the Karkheh dam is the case study of this research. The reason for selecting this region is evaluation of effects of dam construction on river bends.The number of bends was 24 in 1996 (before construction of dam) and was 42 in 2011 (after construction of dam). Important results of this research are: 1-For $R/W

By increasing the world population and more need to supply food, farmers attend to use of chemical fertilizers, organic manures and pesticides. Also, applications of these agents without attention to their side effects, cause more problems to human health and environment. Nitrate is one of the most important elements of organic manures, which leach through soil to surface and ground waters by irrigation or precipitation. So, it’s necessary to monitor the behavior of it. The purpose of this study was to determine the nitrate transport through two different soil textures, loam and silt loam via application of organic fertilizers. In this study, experiments were carried out by cylindrical drained plastic lysimeters with 100 cm height and 60 cm diameter, filled by uncondensed soil up to 60 cm height. Three different organic manures (poultry, cow and sewage sludge) were used on top soil of lysimeters by the rate of 35 tone/ha (upon the average use amounts of farmers). 24 lysimeters were prepared; 9 lysimeters for 3 types of manure with 3 replicates and 3 without manure used as control for each soil type. The results were analyzed by a factorial experiment in a completely randomized form statistical design. Irrigation was done by one week intervals, totally three times with well water. Five drainage water samples (100 ml each sample) were taken through the first pore volume drained after irrigating of lysimeters. It means that each pore volume divided to 5 equal parts for sampling. The results showed that the nitrate concentration in loam soil was more than silt loam soil in drainage water samples, so it can be attributed to the effect of soil texture. Also for both soil textures, sewage sludge treatment was caused the most nitrate concentration, and the least was monitored in control treatment. The amounts of poultry and cow NO3 in drainage water samples were between them, respectively. Considering the one week irrigation intervals and three consecutive irrigations which were done, the amount of contamination in both soils in the first week was highest and in the third week was the lowest; it can be related to nitrate leaching by irrigations done.

Water and nitrogen are the main limiting factors affecting agricultural production in arid and semiarid regions. Therefore, improving the efficiency of these factors is very important. The method of fertilizer application is affecting water and fertilizer use efficiency. The objective of this study was to investigate the effect of furrow fertigation on fertilizer use efficiency (FUE), water use efficiency (WUE), and corn yield. A field experiment was carried out in furrows which have 165m length and 0.006 (m/m) slope in Karaj. The corn Hybrid 370 double-cross was planted on June 2008. A factorial design based on randomized complete block design with 4 replicates. Four levels (0, 60, 80 and 100%) of the recommended fertilizer value and four levels (60, 80, 100, and 120%) of the irrigation water requirement were applied. These 16 treatments were compared with traditional fertilizer application method. Fertilizer treatments were accomplished in four critical stages of the growth (before cultivation, in seven leaves stage, shooting stage and Flowering stage) for fertigation treatments and two stages (before cultivation and seven leaves stage) for the traditional method. Results showed that effects of levels of different water and fertilizer on yield component were significant. Water use efficiency (WUE) was significantly affected by nitrogen rate. On the other hand, water treatments significantly affected fertilizer use efficiency. Increasing fertilizer increased water use efficiency. Increasing water levels to 100% of ETC resulted in increasing fertilizer use efficiency. Highest yield was obtained from the full irrigation treatments (W100%). Albeit the difference among W120%, W100% and W80% was not significant (P=0.05), because W100% was always higher than W120%, treatment of W80% recommends as optimum water level for arid and semi arid region. The maximum and minimum WUE was 2.24 and 0.66 (kg/m3) in W80%N100% and W100%N60%, and The maximum and minimum FUE was 29.85 and 8.52 (kg/kg) in W100%N100% and traditional method, respectively.

Determining saturated hydraulic conductivity (Ks) is one of the important soil characteristics that its estimation is important in soil and water studies. There are several methods for estimating Ks in unsaturated conditions. These methods include the inversed-auger-hole method, the double-ring infiltrometer and the single-ring pressure infiltrometer. The measurement of Ks by these methods requires large volumes of water and long period of time. The Simplified Falling Head (SFH) technique is for rapid determination of Ks, using small volumes of water and easily transportable equipments. The SFH technique appears hopeful and suitable for detailed and repeated sampling, also, over large areas. In this study, Ks was measured by SFH method, double-ring and single-ring pressure infiltrometers for evaluating SFH method. Results showed that in a loam soil, the SFH method estimate higher values for Ks, compared with the double-ring and the single-ring pressure infiltrometers (respectively 9.6% and 18.5%). Statistical analysis of the results of above methods showed that there is no significant difference between Ks values (P

Understanding distribution of physical and chemical soil parameters is very important in recognizing, planning, and soil and water resources management in precision agriculture. Regard to the problems related to direct measurement, finding solution to estimate these parameters are very essential. The purpose of this study was to evaluate the spatial variation of some soil parameters such as; soil salinity, pH and CaCO3 percentage using different methods of interpolation and then to select the most suitable method for estimation of the proposed parameters in the Boukan region with total area 2992 Km2. Totally, 183 soil samples were taken from 0-30 cm soil depth in order to cover whole studied area and the amount of salinity, pH and CaCO3 percentage were measured in all soil samples. Then, different interpolation methods (kriging, cokriging, weighted moving average with powers of 2, 3, 4 and 5 and TPSS with powers of 2, 3, 4 and 5) with ArcGIS and GS+ software were used to analyze data. The proposed methods were evaluated by MAE (Mean Absolute Error) and MBE (Mean Bias Error) statistics indexes. The results of this study showed that the cokriging method with minimum MAE 0.218, 0.156 and 7.353 for salinity, pH and CaCO3 percentage respectively, is the most accurate method.

There are two important parameters in determining the suitability of land for crop production oramount of required water for leaching in saline soils: (1) the spatial distribution of salinity (ECe); and (2) pH in different depth of soil. Collecting sufficient soil samples and analyzing them are both time consuming and expensive. Therefore, it is essential to find alternative methods to easily estimate such parameters and with lower costs. Given that salinity and pH values are known for a particular depth, the same can be calculated for other depths since they are spatially correlated. There are two methods to estimate and prepare ECe and pH distribution map for different soil depths: Kriging and Cokriging methods. The aim of this study was to compare the results of these methods by determining the spatial distribution of salinity and pH in three soil depths 0-30, 30-60 and 60-90 cm in Boukan region; and to find out the spatial correlation among them. The results show that there is no significant difference between the two methods.Therefore, Kriging method is suggested, especially in the case of equal numbers of data and similar fitted models.

Evaluating drainage systems, exploring their strengths and weaknesses, provides a comprehensive perspective to designers and organizers for optimum design and implementation of guidelines for the future. This study was conducted at an experimental site consisting of three plots on a subsurface drainage network under operation in Behshahr, a coastal region in northern Iran. To evaluate system performance,discharge rates from laterals and the depth of water table between laterals were monitored for a period of three months during the autumn. A second degree equation similar to the Hooghoudt formula was developed to show the relation between the hydraulic head and discharge rate. This equation was used to estimate the hydraulic conductivity (K) and equivalent depth (d) of the impermeable layer. The obtained K for the three plots ranged from 1.4 to 2.4 md-1, which was greater than the design value. This analysis also showed that the laterals were placed on the permeable layer. The Glover-Dumm equation was used to show the rate of water table fall and to calculate the specific yield () S y and reaction factor (α). Based on these results, the actual α was 8%, which is greater than the design value of 4%, and the average S y obtained was 5.7%, compared to the design value of 7.7%. From these results, it can be concluded that the lateral spacing was overestimated.

By evaluating the performance of the current drainage systems and exploration of their strengths and weaknesses a comprehensive perspective can be given to designers and organizers for optimum design and implementation of drainage systems for future plans. This study was conducted to evaluate the performance of subsurface drainage systems using rice husk as envelope in Behshahr, a coastal region in the northern part of Iran. For this purpose, eleven piezometers were installed between two subsurface drains designated as S3PD14 and S3PD15. Subsurface drainage system was monitored during rainfall seasons in 1383 and 1385. Parameters such as daily water table fluctuations and drain discharge rate were recorded. The overall conclusion was that subsurface drainage system performance was not satisfactory due to poor control of water table depth and low water discharge, which was mainly because of the drain envelope clogging. Therefore, the Hooghoudt’s equation should not be used for evaluation of design parameters, due to the fact that this equation is only valid for normal conditions (envelope without clogging).

Drainage water created from irrigation and drainage projects in south of Khuzestan province are saline and its disposal to rivers such as Karoon river is faced with certain constraints. One of drainage water disposal strategies is using evaporation ponds, in which the most important outlet is evaporation. Evaporation rate of saline water of these ponds is lower than fresh water. In this study the evaporation rate of implicit ponds for drainage water control in Mirza Kuchak Khan Project was estimated by adjusting the saturation vapor pressure equation of saline water with regard to pure water and by using of Penman equation. Finally, using the evaporation and the annual drain water volume, the required area of evaporation ponds was determined. By evaporation of water from ponds the salinity of water increases. This increase of salinity continues until the salt saturation threshold is reached, and then salts precipitate. The most common salt in drainage water of Khuzestan province is NaCl which has a saturation threshold of 300 g/lit. The results showed that the average annual evaporation of water with 300 g/lit salt is 1903 mm. The drainage water volume produced from Mirza Kuchak Khan Project (12,000 ha area), requires evaporation ponds as big as 7740 ha. This study showed that disposal of the drainage water of sugarcane projects is impossible if only evaporation ponds are used, and therefore, other management options should be considered for reducing the volume and salinity of drainage water.

The growing season climatic parameters, especially rainfall, play the main role to predict the yield production. Therefore, the main objective of this research was to find out some possible relations among meteorology parameters and drought indexes with the yield using classical statistical methods. To achieve the objective, ten meteorological parameters and twelve drought indexes were evaluated in terms of normality and their mutual influences. Then the correlation analysis between the barley yield and the climatic parameters and drought indexes was performed. The results of this study showed that among the drought indexes, Nguyen Index, Transeau Index, Rainfall Anomaly Index and Standardized Precipitation Index (SPI24) are more effective for prediction of barely yield. It was also found that the multivariate regression is better than the univariate regression models. Finally, all the obtained regression models were ranked based on statistical indexes(R,RMSE and MBE). This study showed that the multivariate regression model including wind speed, sunshine, temperature summation more than 10, precipitation and Nguyen index is the best model for prediction yield production in Miane. Average wind speed and Nguyen index were recognized to be the most effective parameters for yield production in the model.

Increased chemical compounds in soil are the most important results of irrigation with domestic wastewater and treated effluents which contain some nutrients such as phosphorous (P). This process could increase the soil fertility, leading to the decrease of chemical nutrient consumption and consequently the cost of agricultural production. A research project was carried out in Tehran region for two years in order to investigate the capabilities of soil and plant in absorption and storage of wastewater contaminants, namely, phosphorous, and also the transmission of them to drain depth as a result of irrigation practice. To do the research, a series of lysimeters based on a statistical factorial experiment in the form of randomized complete design (3x3x3) were used. Raw and treated domestic wastewater, obtained from Ekbatan Housing Complex, and well water (control) were used to irrigate raw edible vegetables including parsley, carrot and tomato. The results showed that the amount of phosphorous leaching through soil to drain depth was between 0.90% and 3.56%, and between 1.03% and 4.15% of the phosphorous concentration in raw wastewater and treated one entered into the soil, respectively. Also, mass balance analyses showed the average phosphorous reduction ranged from 97.2% to 99.9% of the phosphorous entered with wastewater. During two years of study, the maximum concentration of PO4 measured in drained water was about 0.21 mg/L obtained from lysimeters irrigated with raw wastewater. This was much lower than the permissible PO4 amount for discharging the effluents to the surface water resources (6 mg/L PO4 is permitted by Iranian Environmental Protection Organization).

To determine the water application efficiency in furrow irrigation more accurately, consideration of seasonal and spatial variation of infiltration properties are needed. In addition, the effectiveness of different farm management on infiltration are significant. The main objective of this research was to simulate the seasonal variation (SV) of infiltration coefficients in Kostiakov-Louise equation (KLE) in a cracking soil under two traditional farm managements. Farm studies carried out in a clay-loam soil in Karaj. The two management treatments were soil without wheat residual and soil with wheat residual by a 5 ton/ha rate. There were 22 furrows with 0.75 m width in the farm. KLE infiltration coefficients were measured using inflow-outflow and two point’s methods in six furrows. The results of this study indicated that the SV of a and k coefficients were not significant, but variation of f0 was significant which was simulated with a logarithmic model. The effectiveness of SV on cumulative infiltration (Z) was also evaluated and indicated to be significant that were simulated with a logarithmic model too. Finally, dimensionless parameter such as Z* were developed to predicate Z parameter in different irrigation time, irrigation events and different residual management. Base on the result, although residue management causes a significant difference between value of f0 and Z in two treatments, but it doesn’t effect on trend of variation during the season. It means that the trend of variation is independent of residue in soil. It is probably done because of change in some of soil physical properties such as soil bulk density and aggregate stability.

The operation of an irrigation network is the result of a decision-making system in which three elements, i. e. the physical condition of the structures, control capacity, and hydraulic behavior of canal system, have important roles. The impact of these components is incorporated in the hydraulic sensitivity concept. For this purpose, the sensitivity of structures could be considered as the most important factor in the hydraulic characteristics of a system. The sensitivity analysis approach is one of the flow analysis methods that is used to forecast the flow behavior in several irrigation networks. Baffle Modules are one of the most suitable structures for flow regulating and delivery. In this paper, hydraulic sensitivity equations are presented for this type of structure. Also, the quantitative variations of the sensitivity index have been evaluated under operating conditions and compared with those of theoretical conditions. Then the influence of the sensitivity index variations on the performance of structures has been studied. This study was carried out on some modules of the Qazvin network. The results indicated that the hydraulic sensitivity of these off-takes varies under operating conditions. In some cases, variations were estimated to be more than 100%. The range of discharge variations was twice the predefined acceptable value (20%) in some offtakes.