Experiment And Simulation Of Soil Water Movement After Wide Ridge Furrow Irrigation

Furrow irrigation is a common method of surface irrigation,studying soil water movement in furrow irrigation can provide theoretical basis for the formulation of irrigation system and the selection of furrow and ridge shape.Through reading and learning a large number of literatures about water infiltration in furrow irrigation at home and abroad,this paper adopts the technical route of combining theoretical analysis with numerical simulation based on field experiments to study the characteristics of water depth and soil water movement in furrow under different furrow width and furrow depth after wide ridge and furrow irrigation.The main results are as follows:(1)The influence of furrow width and depth on the variation of water depth in furrow with time is analyzed.The depth of the furrow has little effect on the variation of water depth in the furrow with time,and the furrow width has a significant effect on the water depth in the furrow with time.The larger the furrow width is,the slower the water depth in the furrow decreases,and when the furrow width is 50~60cm,the change of the furrow width has the most significant influence on the law of water depth variation with time in the furrow.An empirical model of the relationship between water depth in furrow and time is established,and the relationship is exponential function.Through the applicability analysis of the model,it is found that the calculation accuracy of the model is higher and the applicability is better.(2)The characteristics of soil water movement under different furrow widths and different furrow depths were analyzed.Studies have shown that the width of the furrow has a greater impact on the cumulative infiltration of soil water infiltration,the greater the furrow width,the greater the cumulative infiltration;the furrow width has a great influence on the lateral wetting front migration distance,the greater the furrow width,the greater the lateral wetting front migration distance;furrow depth has a great influence on the cumulative infiltration of soil water infiltration,the greater the depth of the furrow,the smaller the cumulative infiltration;furrow depth has a greater impact on the vertical wetting front migration distance,the greater the depth of the furrow,the smaller the distance of the vertical wetting front.(3)The cumulative infiltration model of soil water infiltration under the influence of furrow width and furrow depth is obtained,and the wetting front migration distance model was established too.It is found that the cumulative infiltration is exponentially related to time,and the wetting front migration distance is exponentially related to time.The functional relationship between furrow width and furrow depth with the parameters in the model is established,and validated the model by using the experimental data,the results show that the model has good applicability and high accuracy.(4)The characteristics of soil water movement and the distribution of water storage at different locations from the head of furrow were discussed.The irrigation quality under different combination conditions of furrow width and depth was evaluated by using irrigation uniformity,irrigation efficiency and water storage efficiency.The optimal combination of furrow width and furrow depth was determined,that is,the width of furrow was 50 cm and the depth of furrow was 20 cm.In this paper,the water depth and soil water movement in wide ridge furrow after irrigation were studied.Due to the limitation of time and experimental conditions,the characteristics of soil water movement in wide ridge furrow irrigation under the condition of root water absorption and the characteristics of soil water and fertilizer movement in wide ridge furrow irrigation under fertilization conditions need to be further studied.