Research On Response Laws And Simulation Of Soil Water Under Different Rainfall Conditions

Soil water refers to water storage in soil unsaturated zone, which is not only the ties of soil plant atmosphere continuum(SPAC), also is the material basis for plant growth and survival. Under intensifying water conflict context, how rational and efficient use of water resources has become one of the hottest issues of our time people’s concerns. So analysis of soil moisture movement in natural and artificial conditions is particularly important. In this paper, taking clay as an example to research the spatial and temporal characteristics of precipitation and soil moisture from 2013 to 2015 Guiyang Huaxi site, soil moisture responses of different rainfall and soil water movement simulation model. The study, in the one hand hopes to enrich the soil water research case,on the other hand, hopes to provide scientific and technological support for drought monitoring and early warning, having science theoretical and practical value. The main conclusions of this paper are as follows:(1)Analysis of soil moisture, respectively, from the two aspects of temporal and spatial variation with rainfall, soil moisture, and results showed that the size of rainfall in time substantially positive correlation between changes. From the vertical variation of soil moisture, the lower the amplitude of the more significant changes in the depth of the soil layer, the deeper layers of soil depth and soil moisture greater the amplitude smaller. The soil moisture change stabilizing layer is basically in a relatively stable state.(2)Response of soil moisture to different rainfall.In case of the absence of rainfall, soil moisture and soil depth was positively correlated, the greater the deeper layer of soil depth of soil water content. Wherein the average minimum soil surface moisture, the greater the greater the depth of soil moisture averages. Rainfall in the process, changes in soil moisture affected by rainfall, initial soil moisture and soil layer depth of varying amplitude variation, the greater the greater the magnitude of rainfall change, the greater the initial soil water content, the lower the magnitude of the change, the lower layer of soil depth greater the variation width. With rain stopping bleeding time extended surface soil water content was significantly reduced volume, lower volumetric water content of soil, there was a small area first after rising gradually reduced in the process, to the impact of changes in soil moisture stabilizing layer of soil moisture is largely unaffected by rain. Through correlation analysis shows that the absence of rainfall state, there were significant correlations between soil moisture at different depths. And in a state of rainfall, rainfall and surface soil water content basically there are also a significant correlation.(3) Analysis of soil water movement mechanism and operation principle of HYDRUS-1D model and optimization the inversion parameters optimization according to the measured data on the HYDRUS-1D model. In accordance with the measured soil moisture and Simulation of soil moisture between the simulation efficiency coefficient, relative error, root mean square error of the three indicators of HYDRUS-1D model to analyze Simulation consequences. Results show that the HYDRUS-1D model simulation effect appears well in this experiment on soil water movement.