Simulation of Water Movement in Soil in Drip Irrigation System in Different Types of Soils

Study of water movement in soil requires adequate knowledge of soil hydraulic properties. This research has been conducted in Shahrood in a sandy loam soil with onion crop to study the moisture distribution and water movement using emitters of drip system. Water movement and moisture distribution in soil were simulated with Hydrus-2D model for different types of soils. The results revealed that if the soil hydraulic properties are estimated correctly and model is calibrated and validated perfectly, and modeling area is defined with correct boundary conditions, it will simulate water movement in soil with high capability. The simulation practice has been done in five types of soils. Results of simulation showed that in all types of soils reduction of moisture distribution in first and middle layer of soil is higher than lower layer but up to 48 hours adequate moisture is available in soil and active plant root zone do not suffer moisture deficit. The final result of simulation of water distribution in different types of soils revealed that if the drip and fertigation systems are designed and operated properly, it will minimize water percolation below the crop root zone and estimation of exact amount of drainage water below crop root zone is possible with selected model.