Estimated model for spatial moment character parameters of wetted pattern under furrow irrigation infiltration

In order to further improve the practicality of moment analysis theory on the study of the transport characteristics of wetted pattern under tow-dimensional infiltration of furrow irrigation, the effects of initial soil water content, water depth, bottom width and slope parameter on the spatial moment character parameters of soil wetted pattern under free infiltration were studied quantitatively by combination of numerical simulation and theoretical analysis method. The function relationship between the spatial moment character parameters of soil wetted pattern and the main influence factors was established. The results showed that the mass center of vertical soil moisture distribution is greatly influenced by initial water content, water depth and bottom width. The average dispersion of the horizontal wetted front is mainly influenced by initial water content, water depth, bottom width and slope parameter, while the average dispersion of the vertical soil wetted front has higher sensitivity to initial water content and water depth. Then, the reliability of the model was further verified through several different soil textures. The results showed that the values of spatial moment character parameters estimated by the proposed model at different infiltration times agree well with calculated values based on the simulation results by the HYDRUS software. The mean absolute values of the relative error of all combinations were lower than 8.5%, and there was no significant difference, which indicated the proposed model can be used to estimate the spatial moment character parameters of soil wetted pattern under furrow irrigation with a high reliability. The results can provide theoretical basis and technical support for the design and management of furrow irrigation.