Research And Application Of Philip Infiltration Model Parameters Prediction

Soil water infiltration is an indispensable link in the water cycle of nature. Among various types of water, soil irrigation water is the most important; therefore, the study on soil infiltration characteristics to determine the reasonable irrigation quota and techniques can maximize water conservation, and thus greatly ease the pressure of water shortage. Funded by agricultural and technological research project of Shanxi Province in2010,"Parametric Study on Water-saving Irrigation Techniques for Shanxi Ground Border Irrigation"(Project No.20100311124), the thesis selected three irrigation areas (Yumenkou irrigation area in Yuncheng city, fenxi in Linfen city and Wenyuhe in Lvliang city) and70irrigation points in four counties (Zezhou county in Jincheng, zhangzi county in Changzhi, Fangshan county in Lvliang and Yuanping in Xinzhou). In the study, a series of experiments were conducted:outdoor infiltration and digging soil experiment, indoor particle analysis and organic matter and salt determination experiment, supplemented by a combination of experimental and theoretical studies. The typical farming soil in seven test areas of12counties (districts) was carefully selected to measure soil infiltration capacity, soil bulk density, soil (volume) moisture content, soil salinity, soil texture and soil organic matter content in three states. Soil infiltration capacity was reflected by infiltration amount and infiltration rate. By means of statistics, the temporal variation regularity of soil infiltration characteristics in these areas within agricultural production cycle and a variety of factors infecting soil infiltration characteristics were researched systematically; the relationship between the two parameters(S and A) of soil infiltration model Philip and various physical and chemical parameters of the test areas was also analyzed in the thesis. By using multiple linear regression, the diverse nonlinear regression and BP model ground method, the study built parameters of the soil infiltration capacity and infiltration model, and transfer function of the soil among the conventional physical-chemical property parameters was also obtained; meanwhile, statistical analysis was used to verify the model. And thus, the parameters of the soil infiltration capacity and infiltration model could be determined by conventional parameters of field soil physical-chemical property. According to Daejeon data, Daejeon soil infiltration parameters under the condition of border irrigation were predicted resorting to Philip model. It was proved that soil infiltration curve could be described by Philip model.The research results showed that:1, Soil bulk density, soil (volume) moisture content, soil salinity, soil texture and soil organic matter content were the major factors affecting soil moisture infiltration. By using the factors as model input parameters, better prediction results could be obtained.2, By means of multiple linear regression model, multiple non-linear regression model and BP model respectively, the soil infiltration capacity and infiltration model parameters were predicted with conventional soil physical parameters, and the three models were compared and analyzed. The results showed that the relative error of BP model was8.9%, ranking the first; relative error of non-linear regression model was13.6%, ranking the second; relative error of the linear model was15.5%, ranking the third.3, There was a correlation among the soil infiltration capacity, infiltration model parameters and physical characteristics of soil. Regardless of the physical characteristics of the soil, however, the soil infiltration capacity experienced the change:from big to small, reaching stability in the end, which met Philip parameters soil infiltration empirical model.4, The two parameters of soil water infiltration model Philip (S,A) had been related with physical and chemical factors of soil.The innovation of this paper:1, By means of Philip model, Matlab and Excle software, the research conducted a comprehensive study on soil ground infiltration problem based on scientifically analyzing the soil infiltration experimental data.2The soil infiltration parameters prediction model were given in74test points of seven test areas in Shanxi Province.3Variables, including conventional soil bulk density, soil (volume) moisture content, and soil texture (sand, silt and clay) were supplemented with soil salinity, which could predicate more accurately, comprehensively and precisely.To solve the increasingly-tense contradiction between supply and demand of water resources in China, the fundamental way is to improve surface irrigation technology and develop border irrigation and sprinkler irrigation. The thesis conducted in-depth research on the key issues of the ground water-saving irrigation-soil infiltration parameters, created a new method to indirectly determine the transfer function of soil infiltration parameters through soil conventional physical and chemical property parameters. Therefore, this research can not only promote the development of soil infiltration theory, but improve surface irrigation technology and utilization of irrigation water as well.