Abstract:Abstract: Infiltration irrigation is a promising water-saving technique. The characteristics of infiltration irrigation material greatly affect the water use efficiency. However, little studies have focused on the material components and hydraulic conductivity. This paper was aimed at acquiring the quantitative self-adjusting water-conduction characteristics of infiltrating irrigation material (composed by montmorillonite MMT and polyacrylamide PAM) with its components and soil moisture. The Gaussian mixture model was used to simulate and calculate the relationship function of balance hydraulic conductivity of infiltrating irrigation material, component proportion and soil moisture. Infiltrating irrigation materials with 9 different ratios of components(MMT:PAM =5:1, 7.5:1, 10:1, 12.5:1, 15:1, 17.5:1, 20:1, 22.5:1, 25:1)were prepared. The material was ovendried and condensed into solid and then ground into power ≥37μm, weighed into a glass tube (diameter in 5 mm and height in 200 mm) with both ends fixed with degreasing cotton for tests. The glass tube was marked with scales. The experiment was conducted in a laboratory under different soil moisture conditions (3%, 5%, 7%, 5%, 11%, 13%, 15%, and 13%). The glass tube filled with material was immersed into soils with different moisture. There was enough water in the glass tube for water supply. The dry weight of soil placed in a beaker was about 250 g. The beakers were put into an artificial climate box with the humidity and temperature of 50% and 25℃ to ensure that the soil environment did not change with the environment outside during the experiment. Water height was recordedevery 2 h when the water-conductivity balance state was reached after 24 h. The data were used for establishing modes describing conductivity, components and soil moisture relationship. In addition, another materials with different component ratios (MMT:PAM=8 and 18) under 2 different soil moisture(4% and 14%) were applied for model validation. There was a total of 72 experimental points for model establishment. The Gaussian mixture model was fitted using MATLAB toolbox cftool. The results showed that the relationship between hydraulic conductivity and component ratios under different soil moisture could well fitted by Gaussian mixture model with the determination coefficient higher than 0.9 and the root mean square of error (RMSE) of 4.981-25.87 g/h. Obvious peaks were present in the fitness curves, which may reflect the interaction of material itself and soil moisture. On water balance, the material was of even swelling structure, which facilitated water conduction in materials and thus led to peaks of hydraulic conductivity. From the fitness, the model parameters could be obtained and these parameters had good exponential relationship with soil moistures with determination coefficient about 0.9 and RMSE smaller than 195 g/h. When those parameter values were used for validation, the relative errors of measured and predicted hydraulic conductivity were 0-14.14%, less than 20%. It indicated the Gaussian mixture model could well describe the relationship between hydraulic conductivity of infiltrating irrigation material, material composition and soil moisture. However, the results need to be validated in field and more studies on influential factors of hydraulic conductivity of infiltrating irrigation material should be carried out. This study has a guiding role on subsequent infiltrating irrigation material preparation and application.