Using HYDRUS-2D Simulate Soil Water Dynamic in jujube root zone under drip irrigation

Drip irrigation is considered one of the most efficient irrigation systems. Alternatively to the traditional surface irrigation systems, drip tube can only supply water for root zone. However how to irrigate timing quantitatively for root zone usually depended on the reasonable irrigation schedule. In many methods, the one which formulate by using soil moisture absorption and consumption is considered the most scientific. As hourly observation soil moisture content of the whole jujube root zone is difficult to achieve. Numerical models is represent powerful tool to simulate the soil water dynamics in root zone during the growing season, to obtain the data of soil moisture content hourly and to explore the regularity of soil moisture absorption and consumption. In the paper, HYDRUS-2D model is chosen to simulate the soil water dynamics in the section of jujube root zone with considering the two-dimensional root water uptake. The goodness of fit between simulation and measurement are measured by using the root-mean-absolute-error (RMAE) for the simulated with measured volumetric soil water contents. The results show that the RMAE values for the 90 day's soil water dynamics at soil layers of 20cm, 60cm, 80cm, 100cm below drip tube are 14.2%, 13.0%, 1.1%, 1.0% respectively; the RMAE values for simulation section of before, after irrigation are 5.1%, 4.3% respectively. Indicating the model perform well in simulating soil water dynamic during the growing reason.