Study On Water Infiltration Characteristics Of Red Soil Under The Condition Of Bubble Irrigation

In this dissertation,the red soil of Jiangxi Province was used as the object of study.The effects of flow,irrigation amount,initial soil water content and soil texture on water infiltration were analyzed by indoor experiment and HYDRUS-3D numerical simulation.The effects of soil water Migration rules,the conclusions can be applied to the development of irrigation parameters of Bubble irrigation.The main conclusions of this paper are as follows:(1)It is found that the shape of the soil moisturizing body is similar to that of the rotating object in the case of the infiltration test,and there is a significant parabolic relationship between the wetting front distance and the vertical direction.The maximum radius of the wetting body in the horizontal and vertical directions increases with the infiltration time,and there is a significant power function relationship between the horizontal and vertical infiltration distance and the time.Under the same conditions,the lower level of the outlet and the vertical wet front migration rate of the Bubble irrigation are slowed down with the infiltration time.(2)Under the condition of infiltration,the flow rate,bulk density and initial moisture content become larger or smaller,and the wetting ratio decreases with the increase of time.At the same time,the wet ratio is larger than the size The flow rate is small,the density is obviously smaller than the bulk density,the initial moisture content is significantly lower than the initial moisture content is low;three factors under the wet ratio and time there is a significant power function relationship between.(3)Based on the simulation of the flow conditions of the three flows,The relative error between the simulated values of the soil moisture content and the measured values is small,and the moisture content profile after the irrigation The results are in good agreement with the measured results.(4)Under the condition of numerical simulation,the effect of flow on the wetting body: the size of the wetting body and the size of the high water cut area in the wet body increase with the infiltration flow rate.The effect of irrigation amount on the wetting body:the volume of the wetting body increases with the increase of the irrigation amount,and the volume of the wetting body increases with the increase of the flow rate when the irrigation amount is the same.With the distance from the irrigation center,soil moisture began to decrease.The effect of initial moisture content on soil moisture migration: The wetting circle caused by infiltration increases with the increase of the initial water content,and the moisture content of the initial volume at the same cross section is increased.The effect of soil texture on the water movement of moist soil in Bubble irrigation is: the sizeof the wetting peak is smaller than that of the clay.The volume of the wetting body is smaller than that of the clay.The content of the clay is low,High moisture content of the size of the region,the high content of clay particles is much higher than the low content of clay particles;low clay content of the wet body is round,and high clay content of the wet body is oval.