Assessment of influence of installation depth of emitter with same discharges on moisture distribution in subsurface drip irrigation system and simulation with HYDRUS-2D model

Subsurface drip irrigation is now considered as one of the most advanced methods of irrigation in agriculture. In subsurface drip irrigation will be given water to plant in low volume and pressure and will be moved by the force of the soil matric. These factors reduce losses and increase water use efficiency as a result. It should be noted that lack of proper and improper management of these irrigation systems، which reduces their efficiency in water use. To investigate the distribution of moisture content and depth of subsurface drip irrigation system installed and optimized flow design with 2 ls-1 emitter discharge، the depth of installation tubes (30 and 45 cm) and four layers deep moisture readings (0-30، 30-60، 60-90 and 90-120 cm) in a farming soil at the agriculture researches center of Kerman. The results of the simulation of moisture by the HYDRUS-2D model were compared with results from field experiments. Average of Root Mean Square Error (RMSE) and correlation coefficient (r) values were obtained respectively 0. 0065 and 0. 992 for Installation depth of 30 cm. Average of RMSE and r values were obtained respectively 0. 0085 and 0. 977 for Installation depth of 45 cm، which showed the model capable in simulating the distribution of moisture in the subsurface drip irrigation system. Comparison of correlation coefficient in both of depths in the linear model fitted in both cases were indicated higher accurately of estimates of 30 cm to 45 cm Installation depth. Also the installation depth of 30 cm was selected as the optimal installation depth.