春小麦垄沟灌土壤水分入渗数值模拟

Numerical simulation on soil water infiltration for spring wheat under ridge furrow irrigation

小麦垄作沟灌是在耕作形成的垄面种植作物、垄沟内灌溉的一种耕作方式,由于小麦自身生长所需土壤水分沿灌水沟断面以纵向下渗和向垄体横向侧渗供给,研究不同土质与垄宽在设计灌水定额一定条件下的沟灌灌水效果。文中依据非饱和土壤水动力学理论,以甘肃石羊河流域下游民勤沙漠绿洲区春小麦垄作沟灌为例,采用典型实测土壤水分运动参数,应用HYDRUS数值模拟软件计算分析砂质粘壤土和粘土在不同垄宽沟灌土壤水分运动规律,建立沟灌土壤水分二维入渗模型,从提高灌水均匀度角度评价灌水效果。研究结果表明:在不考虑停止灌水后水分再分布情况下,砂质粘壤土垄宽不宜大于45cm,粘土不宜大于30cm。研究结果为春小麦垄作沟灌技术参数进一步研究提供一定的理论基础。

Ridge -furrow irrigation for spring wheat is one kind of planting ways that crops are planted on the ridge surface and irrigated in the furrow, so the soil moisture can vertically infiltrates along the irrigation ditch cross - section and horizontally infiltrates to the ridges. Studing the different soils and wide ridge furrow irrigation effect in the design irrigation quota certain conditions is needed. Based on unsaturated soil water movement theory, taken ridge furrow irrigation of spring wheat in the Minqin desert oasis, downstream of Shiyang River Basin, Gansu for example,we selected typical soils and measured soil water parameters, at the same time analyzed of water movement on sandy clay loam and clay at various parameters with ridge -furrow irrigation by using HYDRUS model, as well as developed a numerical simulation model to understanding of soil water movement in two - dimensional under furrow irrigation. Then we evaluated irrigation effects from the point of view of increase irrigation uniformity. The results show that the ridge width should not be greater than 45cm in sandy clay loam and 30cm in clay without considering the cessation of irrigation water redistribution circumstances. The results provide a theoretical basis for the ridge -furrow parameters further study in arid region.