Study On Numerical Simulation Model Of Soil Moisture Of Dry Land Under Different Growth Conditions

The unsaturated soil moisture is the source of survival of terrestrial plants, surface water and groundwater are closely connected, is an important link between them. This paper is based on the theory of soil water dynamics, established a one-dimensional model of soil moisture movement of unsaturated soil, on the basis of field measured data, the movement of soil moisture were simulated. The use of numerical calculation method were under bare ground conditions and crop growth conditions have been simulated, obtained the movement of soil moisture.By comparing the simulation results with the measured data analysis to study the change of soil moisture of bare ground and changes in soil moisture under the various stages of crop growth conditions and effects of different mulching and tillage on soil water content between2009-2012years in Wenxi Experiment Station. To provide a reasonable theoretical basis for the irrigation and fertilization system and soil moisture prediction, the main conclusions are as follows:1. According the unsaturated soil moisture movement equation, a soil water movement model of vertical one-dimensional conditions is established, using the implicit finite difference method, The soil water movement model is transformed into the form of equations, and the parameter in equations are linearized by using the iterative method.through the esta-blishment of the model, numerical simulation is carried out to measure the test data under the condition of bare ground between2009-2010years in Wenxi Experiment Station, and the simulation results were compared with the measured data to verify the reliability of the model.Using The model to predict the dynamic change of the soil moisture between2010-2012in Wenxi Experiment Station, the simulation results agree well with experimental results.2. Combined with the soil root water uptake mechanism, established the corresponding root water uptake model, and the establishment of the soil water movement under the conditi-on of one dimension model of crop growth. The movement of soil water evaporation and rai- nfall conditions were predicted by the numerical simulation,and use the measured data from jointing to maturity of winter wheat of Wenxi County in2009, The reliability of the model was verified by numerical simulation method. On this basis,the variation of soil moisture movement from jointing to maturity of winter wheat between2010-2012were predicted, the simulation results agree well with experimental results. Shows that the model can reflect the patterns and characteristics of soil water movement of crop growth conditions. Also analyzed the soil water movement of winter wheat under different covering methods,different tillage and the different organic, and analyzes the reasons for its change.