Parameters simplification of Green-Ampt infiltration models and relationships between infiltration and soil physical parameters

Simplifying the Green-Ampt infiltration model type and reducing its number of parameters have important significance for the practical application of the model. Based on the derivation of the relationship between the average matrix potential suction of the wetting front and the soil sorptivity of Philip model, the simplified Green-Ampt infiltration model was proposed. Using the field observed data obtained from two loam soil fields of 222 corps in Xinjiang province, the relationships between parameters of simplified Green-Ampt model and soil physical parameters were analyzed and then the quantitative experience conversion function was constructed. Results showed that infiltration parameter A was logarithm negative correlated with initial water content, and the correlation coefficient was 0.77. A was exponential negative correlated with soil compaction and clay content, and the coefficient was 0.70 and 0.74 respectively. Saturated hydraulic conductivity Ks was exponential negative correlation with soil compaction and clay content, and the coefficient was 0.74 and 0.73 respectively. High multiple linear correlation was found between A and soil physical parameters, and the correlation coefficient was 0.90. There was medium multiple linear correlation between Ks and soil physical parameters, and the correlation coefficient was 0.79. The average relative error between observed data and infiltration parameters obtained by experience conversion function was about 10%. The results indicated that the simplified Green-Ampt model has certain precision in simulating the soil infiltration process.