Study On Forecast Model Of Process Of Soil Infiltration In Purple Soil

Purple soil is important soil resources in the Three Gorges Reservoir Area, because of distribution of precipitation is non-uniformity in space and time ,soil and water losses and the drop of land productive forces what due to rainstorm and seasonal drought occurs frequently is the main reason which limits the local agricultural development The process of soil infiltration is important part of circulation of hydrology in catchment, analyzing thoroughly the characteristic of soil infiltration in Purple soil is the foundation of knowing rule of soil erosion, also solving the seasonal drought and enhancing precipitation degree of utilization in the dry land.We analysized the characteristic of soil infiltration under different land utilization way to model district of Nan Tuo in Fuling area, test serviceability of model of soil infiltration which is more reliable in the domestic and foreign in the Purple soil, filtrating the best model At the same time, method traditional statistic was applied to determine and quantify the spatial variability of soil properties, established experiential forefast model which is between parameter of soil infiltration and soil characteristic, the model parameter of soil infiltration and soil characteristic, the main conclusion as follows:(1) Testing serviceability of the equation of Kostiakov, the equation of Horton , the equation of Green-Ampt and Philip which is comprehensive form in Purple soil, the correlation coefficient of curve is high ,which was computed by the equation of Horton, the predicted value and during the actual value error was the smallest, no matter were in the decline stage what stable stage , might expressed the process of soil infiltration in Purple soil.The effect of simulation is bad which was computed by the equation of Kostiakov, the equation of Green-Ampt and Philip which is comprehensive.The equation of Kostiakov fitting effect to miss in the decline stage, especially in vegetable plot and vegetable plot + citrus fruits, the fitting effect is good in the stable stage relatively. The predicted value of the equation of Green-Ampt and Philip which is comprehensive form was lower than the actual value generally in the decline stage, the predicted value was higher than the actual value in the stable stage, error between the predicted value and the actual value is also the largest.(2) The characteristic of soil infiltration are belong to powerful variability ,the CV% is 210.12%, at the same time, the variability presents the obvious randomness, after the process logarithm transformation, velocity of stable infiltration approximately to obey the normal distribution, the CV % is 105.93%, still presented the greatly strengthened variability.(3) Because the characteristic of soil physics and chemistry possibly is the influence factor what lead to variability of soil infiltration, analysising to the soil physics and chemistry characteristic (grain composition, bulk gravity, porosity, organic matter, aggregates), its C_v was located between...