Introduction: Surface and subsurface drip irrigation (SDI) is widely used in arid and semi-arid regions due to water saving. The precise design of these systems requires a precise understanding of the wetting advances pattern under different condition. Methods: In order to investigate the Moisture distribution pattern in SDI, the laboratory experiments were carried out in a transparent polycarbonate box (0. 5m *1. 22m * 3m) using three different soil textures (i. e. fine, medium, coarse). The drippers were installed at 2 different soil depths (i. e. 15cm and 30 cm). The emitter outflows rates were considered as 2, 4 and 6 lit/hr. Also, these experiments were conducted for two continuous and pulse flow. In SDI with pulse application, the pulse cycles were considered 30-30, 20-40 and 40-20 min. The first number was the irrigation time (on) and the second number was the rest time (off) of the system in each cycle. Findings and Conclusion: The results of this research showed that the Moisture advance pattern moved more horizontally with increasing the rest time for SDI with pulse application. Also, horizontal distribution of Moisture front (for the same water volume) for low emitter outflow was more than emitter with high outflow rate. As well as, the maximum depth of wetted front was related to emitters with higher outflow rate in the coarse texture, and in fine texture is related to lesser outflow rate. The results indicated that the horizontal distribution for pulse ratio 20-40 (these values varied from 68. 38 to 93. 66 cm) was more than two other pulses (these values ranged between 64. 91-85. 94 and 66. 4-81. 19 cm for pulse ratio 40-20 and 30-30, respectively) and continuous application (these values varied from 60. 6 to 83. 82 cm).

Estimating the advance velocity of the Moisture front is one of the important parameters in designing and managing of the drip irrigation system. In this study, experiments were carried out in a transparent plexyglass tank (3*1*0. 5 m) using three different soil textures (fine, heavy and medium). The drippers were installed at 3 different soil depths (surface, 15cm and 30cm). The emitter discharge was considered 2. 4, 4 and 6 lit/hr. Also, these experiments were carried out for two continuous and pulse irrigation systems. In pulse irrigation, the pulse cycles were considered 30-30, 20-40 and 40-20 min. In this research, using nonlinear regression model, empirical models were developed to predict the advance velocity of the Moisture front in different directions. The input parameters of suggested model include emitter discharge, saturated hydraulic conductivity, application time, soil bulk density, emitter installation depth, initial soil Moisture content, the ratio of irrigation time to complete period of each cycle and the proportions of sand, silt and clay in the soil. The results of comparison between measured and simulated values of advance velocity indicated that these models have acceptable precision and accuracy in estimating the advance velocity of the wetting front in different directions. The values of the mean absolute error (MAE) and the root mean square error (RMSE) varied between 0. 031-0. 108 and 0. 067-0. 275 cm/min, respectively.

Moisture front of trickle irrigation system is oUtstanding and important properties to be considered for designing of the system. The dimension scale and direction of Moisture front can increases the water consumption and irrigation system efficiency. Using Super Absorption Polymer (SAP) could be consider to increase water productivity and irrigation efficiency in the soil. The objective of this research is study the effects of SAP on soil properties and the scale of Moisture front. An experimental field complete block design was conducted in four level of SAP in three replications. The difference betWeentreatments was the amount of SAP by 0, 0.1, 0.2, 0.3 percent of soil wight and constant flow volume in three irrigation of time schedule. The result showed that application of SAP improved some of the physical properties of soil. For example the hydraulic conductivity and saturated volume of water and specific gravity. The results also showed that the depth and the Moisture wide of wetted soil Moisture front in first experiment was different compare with other irrigation period.The wide of wetted soil of Moisture front in first irrigation period in wettness treatment is greater than other treatment and this is not true in next irrigation periods but it had smaller front ,Moisture. The standard variation analysis indicated that depth of wetted soil and wide of Moisture front has significant difference in five percent of probability level. Result of comparison among all applied treatments by using 0.3 percent SAP in soil showed significant difference in order to increase the depth and wide of wetted front of soil Moisture.

Introduction The study of Moisture patterns under a single dropper is necessary for the design, management, and implementation of drip irrigation systems. The proper design of these systems should be a desirable combination of dropper discharge, soil characteristics, application time and type of used water that affect the water dynamics in the soil under surface dropper. However, less attention has been paid to the effect of water type, especially magnetic water, on the dynamics of water in the soil. Magnetic fields, while changing the physical and chemical properties of water, lead to changes in the characteristics of water movement in the porous medium. The purpose of this study was laboratory investigation of combined and separate effect of magnetism and organic matter on the distribution of Moisture in layered soils. Material and Methods The experiments were carried out in a 50*50*50 cm box of transparent plexiglass to observe the movement of the Moisture front in the soil. Also, the experimental model of the present study includes water resource, plastic pipe, magnets set for applying magnetic field to water and dropper with a constant discharge rate of 4 liters per hour. In this study, four permanent pairs of magnets were applied with two specific magnets (three pairs of magnets with 0. 2 T, and a pair of magnet of 0. 3 T magnitude). The Porous media treatments of this study includes two samples of sandy loam soil (74% sand, 11% clay and 15% silt) and clayey soil (15. 5% sand, 52. 5% clay and 32% silt) and hydroponics porous media (peat moss organic matter). Soil and hydroponic treatments were prepared in the form of homogeneous mixture of soil (80%) with organic matter (20%). Also, the total thickness of the soil layer was considered 35 cm (the thickness of the coarse textured layer (SL) 25 cm and the fine textured layer (C) 10 cm) that 15 cm was kept empty from the top of box. For this purpose, the effect of plain and magnetic water in the form of eight treatments, on the Moisture movement in coarse-textured, fine-textured, coarse textured mixed with peat moss, fine-textured mixed with peat moss were evaluated. Also this tests in the irrigation and drainage and Soil Laboratories were designed and implemented. Finally, the chemical properties of drainage water extracted from soil samples and samples of soil mixed with peat moss were measured by pH meter (pH meter) and electrical conductivity meter (EC meter). Results and Discussions The results of this study showed that due to the application of magnetism on irrigation water, electrical conductivity of drainage water was decreased in all treatments with the highest decrease to 0. 875 mmho/cm in the fine-textured soil, except the fine-textured soil mixed with peat moss. Also, drainage water pH was increased in all four soil treatments, with the highest increase in the fine-textured soil to 7. 6. Furthermore, Investigation about Moisture dynamics showed that the significant effect of magnetic water application on certain treatments and the patterns of Moisture distribution with their progressive radii were tangible. Also, for infiltration depth factor, the most general variability of magnetic water treatment was observed in T1 (increment), T7 (decrease), T3 (decrease) and T5 (increment) treatments. On the other hand, the highest influence of forward width was obtained in T7 (increment), T1 (decrease), T5 (increment) and T3 (increment) treatments. In addition, the analysis of forward curves-soil Moisture distribution showed that due to the application of magnetic water for example in the horizontal direction, the maximum horizontal progression radius increased by 19. 81% to 38. 9 cm. Also, T7 (the fine textured soil on the coarse textured soil with magnetic water) can be described as a treatment that has the most beneficial result of magnetic water in the present study. As a result, even without using organic matter treatment and application of its fertilizers, it is possible to use the existing condition of agricultural soils with desired results, which have the same status as the present treatment and even the same treatments. In general, the results of this study were indicated that the magnetism on the chemical properties of soil water and especially the dynamic characteristics of water in the soil, including the pattern of Moisture distribution and forward velocity was effective.

The wetted profile pattern is an important factor to consider when designing and managing a surface and subsurface drip irrigation systems. The knowledge of the pattern dimensions is imperative in choosing the suitable spacing between emitters and the correct distance between laterals. The experiments were carried out in a transparent plexiglass tank (0. 5 *1. 22 *3 m) using three different soil textures (sandy clay, sand clay loam, and sandy loam). The drippers were installed at 3 different soil depths (15, 30 and 45 cm). The emitter outflows were 2. 4, 4 and 6 Lhr-1 with irrigation duration of 6 hr. In this study, using the data obtained from the laboratory experiments and conducting the nonlinear regression analysis using Microsoft Excel Solver tool 2010, an empirical model was developed to predict the horizontal distribution of the wetting front for different application times. The suggested model includes estimation of the wetted radius at the top and bottom of the emitter horizontal axis as a function of emitter discharge, saturated hydraulic conductivity, water application time, soil bulk density, emitter installation depth, initial soil Moisture content, and the percentages of sand, silt, and clay in the soil. We pursued a similar procedure in developing empirical formulas for estimating the wetted radius at different soil depths (by optimizing the coefficients of Equations) to predict the full shape of the wetting pattern. The best performance of the model was related to the depth of zero (on the emitter positioning axis), where the values of RMSE, MAE, and R2 were 2. 15, 1. 7 cm, 14. 85 % and 0. 92, respectively. The lowest performance of the model was related to the depth of 20 cm from the emitter, where values of RMSE, MAE, and R2 were 3. 93, 3. 26 cm, 37. 55% and 0. 75, respectively (R2 coefficient was significant at 5% level). The results of this research showed that the suggested model predicted the full shape of wetting pattern with acceptable accuracy. Considering these models in designing subsurface drip irrigation systems could improve system performance.

Among the problems faced by artificial feeding methods, we can mention low rainfall, limited water resources, high temperature and high evaporation, high sediment yield due to poor vegetation cover, etc. Artificial feeding methods in these areas should be designed in such a way that it has maximum efficiency from the available water resources. In this research, it has been tried to reduce the aforementioned problems by presenting a new method of artificial nutrition suitable for desert areas. In order to design a suitable method of artificial nutrition, sufficient information about the distribution of water flow in the soil is needed. On the other hand, research on the distribution of water flow in porous media without modeling the field conditions is time-consuming and expensive. In the current research, the issue of determining the infiltration capacity in the unsaturated environment was discussed using the integration of the infiltration trench and the permeable pipe in the laboratory environment. Method For this purpose, a physical model was built in which water was injected into the unsaturated environment through a permeable pipe and a trench. The input flow to the model included 5 flow rates of 1, 1. 5, 2, 2. 5 and 3 liters per minute. With the beginning of the experiment, which was entered into the model with the mentioned flow rates, the amount of progress of the Moisture front was determined every 5 minutes. This process continued until the Moisture front reached the water level. At the same time as the water was removed from the model, the output flows were measured every 5 minutes. The way water moves in the unsaturated environment and the formation of the Moisture front was photographed and the images were analyzed using Plot Digitize and AutoCAD software. In the next step, after creating a flow in the porous medium, the volume of passing water was measured in different conditions at a certain time. The amount of water output from the model depends on factors such as the flow rate entering the model, the dimensions of the model, the slope of the ponding surface, the distance between the bottom of the trench and the ponding surface, the texture of the soil, the length of the trench, the width of the trench, the height of the permeable pipe to the bottom of the trench, the average diameter of the permeable material, and the entry time. The water depends on the model until it reaches the stagnation level and the time it takes for the water to reach the stagnation level until the end of the test. In the experiments, the input flow to the model was variable and other factors were considered fixed. After the water reaches the stagnation level in time intervals of 5 minutes for 60 minutes (a fixed time, the duration of which is obtained according to reaching the peak output flow rate from the model and preliminary tests for the lowest flow rate) It was measured for all model inlet flow rates. Next, after the completion of 60 minutes, the amount of water output from the model was measured for another 30 minutes. In flow rates of 2. 5 liters per minute and 3 liters per minute, due to the fact that the inlet flow rate was higher than the capacity of the model, the excess water volume overflowed from the model. Then the inlet was cut off and for another 120 minutes, the output flow rate from the model was measured in 5 minute intervals. Then, the volume of water entering the tank (V_in) and the volume of water leaving without calculating the base flow that was mentioned earlier was measured to simulate the static level, V_out=(V_B-V_A). V_A is the volume of water input to simulate the static surface and V_B is the volume of water output from the model. The performance of the model was calculated based on V_out in relation to the volume of water coming out of the model without calculating the base flow rate as maximum 〖(V〗_(out max)) and also V_out was calculated in relation to V_in. Results The highest penetration capacity of the model was determined to be 2. 049 liters per minute. The results showed the trend of changes in the output flow from the model, the time the Moisture front reached from the trench to the reservoir surface, the average infiltration velocity, V_out, the time to reach the maximum output flow from the model, and the slope of the water discharge line from the model after approaching the flow rate proportional to the capacity. The influence of the model has decreased. The performance of the model was evaluated based on V_out during the duration of the experiment in two modes. The best performance of the model was related to the flow rate of 2 liters per minute, which is the closest flow rate to the flow rate corresponding to the infiltration capacity of the model. The results showed that the performance at a flow rate of 2 liters per minute in the case where V_out was measured in relation to V_(out max) (water entering the model is less than the infiltration capacity of the model), 96% and in the case where V_(out max) was compared to V_in was taken into consideration (water flow entering the model is greater than the infiltration capacity of the model), its performance was determined to be 98%. In the presented artificial feeding method, the inlet flow rate through the permeable pipe should be designed according to the infiltration capacity of the trench so that the maximum capacity of the trench is used and water loss is minimized.

One of the most important parameters in designing surface and subsurface drip irrigation systems is the advance velocity of the wetting (Moisture) front in soil, which enormously affects the performance of these systems. In this study, experiments were carried out in a transparent plexy-glass tank (0.5m*1.22m*3m) using three different soil textures (fine, heavy and medium). The drippers were installed at 4 different soil depths (surface, 15cm, 30cm and 45cm). The emitter outflows were considered 2.4, 4 and 6 lit/hr with irrigation duration of 6 hr. Then, using the-p theorem of Buckingham and Dimensional Analysis, equations were developed to estimate the advance velocity of the wetting front (horizontal, downward and upward). The results of the comparisons between the simulated and measured values showed that these equations were very capable of predicting the advance velocity of the wetting front in different directions. The average Standard Error (SE) values at all depths and in all directions (horizontal and vertical) for clay, loam and sandy soil textures were estimated as 0.18, 0.21 and 0.23, respectively which were the evidence for the relative superiority of the developed equations in clay soil texture. Also, the average SE values at all depths and in all soil textures (0.28, 0.20, 0.23 and 0.15, respectively) showed the increase of equation accuracy with the increase of soil depth. Using these equations in designing surface and subsurface drip irrigation systems could improve system performance.

Infiltration parameters are the most important indicators of soil quality. Soil water infiltration is one of the key properties for designing irrigation systems, hydrological studies, water resources management, drainage projects and soil conservation practices in watershed scale. The objective of this study was to investigate the effect of land abandonment on infiltration parameters in semi-stepped rangelands located in Karsanak, Chahar Mahal va Bakhtiari province, Iran. For this purpose, five types of land uses including pasture, agriculture, 3-5, 10-15 and 25 years-long abandonment were selected and the infiltrated water was measured in six replicates by tension infiltrometer apparatus. The results indicated that land use changing led to reduce soil organic matters, soil aggregate stability, soil pores connectivity and to disarranging soil natural pores. Consequently, the negative and significant effect of land use changing on parameters of water infiltration was deduced. Average saturated hydraulic conductivity in pastures (7.4 mm/h) was almost twice of that for agricultural land use (4.4 mm/h). In addition, the sorptivity experienced 30 percent reductions in agricultural lands compared to pastures. However, because of the land abandonment i.e. restoration of vegetation and macro aggregate formation and increasing aggregates stability, the infiltration process was improved such that saturated hydraulic conductivity of the 25 years-long abandonment improved from 4.38 to 6.09 mm/h.

Reuse of wastewater as an important and constant water resource for agriculture that as the world's largest water consumption has gained incredible attention. Wastewater contains a large number of microorganisms of which some can lead to microbial pollution for the environment. There are different management ways to reduce soil surface pollution such as using subsurface drip irrigation and some amendments. Subsurface drip irrigation could reduce the movement of pathogens in the soil. Moreover, Biochar is a carbon material that has gained more attention for removing various pollutions in soil. So, it is necessary to investigate water movement and distribution in conjunction with using tools and methods for preserving water in water scarcity situation and reducing subsequent problems of wastewater use in the soil. The main objectives of this study were (i) to assay the effect of irrigation management, different flow rates, and adding biochar into the soil on water distribution, under subsurface drip irrigation,and (ii) to validate the HYDRUS model for modeling distribution of water and its movement in different conditions in subsurface drip irrigation. The study was conducted in outdoor glasses’,lysimeters (70×60×17 cm) in the research farm of Shahrekord University, Shahrekord. First, the lysimeters' walls were treated with grease in order to prevent preferential flow along the walls. Then, the lysimeters were filled with air-dried clay loam soil. The dripper was installed at the depth of 20 cm below the soil surface. Treatments included two discharge drippers (Q2 and Q4), three levels of maximum allowable depletion (MAD) (30, 50, and 70%), and three application rates of biochar (0, 0. 5, and 1%). Three irrigations were done for each lysimeter based on the defined MAD by polluted water containing fecal coliform bacteria. The soil Moisture content in lysimeters was measured using a Moisture meter device at different times including 1, 2, 4, 6, 8, 10, and 24 hr after ceasing irrigation. Also, the HYDRUS-2D/3D was applied for simulating water movement and soil Moisture content in various treatments under subsurface drip irrigation. Water distribution and Moisture content depends on flow rate and soil hydraulic properties. In the current study, the biochar was an amendment that changed Moisture distribution in soil due to creating various soil hydraulic properties, and it was more effective than MAD. Additionally, biochar affected the soil water content of a clay loam soil at various matric suctions especially between saturated content and field capacity. However, the Moisture content at the permanent wilting point of any biochar rates did not change significantly. The horizontal direction of the wetting front in treatments mixed with biochar was smaller than the control. Treatments with a smaller discharge rate (2 l h-1) created the higher wetted area,because those treatments delivered the total amount of irrigation water in a long time so water had enough time to distribute in soil, in comparison with treatments with higher discharge rate (4 l h-1). Also, the irrigation interval in the biochar amended soils was higher than the counterparts. For all times, a higher soil water content around the dripper was observed at a higher discharge rate. Also for all times and both discharge rates, downward soil water movement was greater than upward soil water movement because capillary forces are small compared with gravity forces, and it can be the main point for soil and human health. It should be mentioned that the amount of Moisture in soil surface in treatments mixed with 0. 5 and 1 % biochar was less than 0% biochar,however, there is no significant difference between all treatments. The lowest and highest Moisture content on the soil surface was observed in Q2B1 and Q4B0 treatments, respectively. MAD 30% with reducing irrigation interval, decreased the Moisture fluctuations in soil surface than MAD 50 and 70%. Moreover, HYDRUS-2D/3D has an acceptable ability in simulating spatial-temporal changes in Moisture under subsurface drip irrigation. The R2 and RMSE ranged from 0. 62 to 0. 78 and 0. 037 to 0. 053, respectively. Overall, the addition of biochar into the soil can reduce the risk of soil surface pollution resulting from using wastewater due to less Moisture in the soil surface in arid and semi-arid regions with water scarcity. The porous structure of biochar improves water holding capacity and decreases evaporation from soils. Also creating a bigger saturated zone, using drippers with high flow rates can be suitable for short root plants.