地下滴灌土壤水运动和溶质运移数学模型的应用

利用建立的地埋点源土壤水运动和溶质运移数学模型描述地下滴灌条件下土壤水、肥运动的分布规律,将土壤质地结构、滴头出流量、滴头埋深和单次灌水历时等因素对土壤水分布的影响进行模拟分析。结果表明,在确定的土壤质地条件下,滴头出流量和埋深是影响地下滴灌系统性能的两个最重要的灌水设计参数,应尽量采用增加滴头数量而不是选用大流量滴头的方法来满足作物的需水要求。此外,合理的灌溉施肥时机应依据当地的土壤质地条件予以确定

Model Application of Water Flow and Solute Transport During Non-steady Diffusion From Subsurface Emitter Source

A model developed by the authors is used to describe flow of soil water and transport of solute during subsurface drip irrigation and fertigation. Impacts on flow of water and transport of solute of factors such as soil texture and structure, discharge rate of emitters, depth of laterals and time lasted in a single irrigation are simulated. Results show that for a specific soil, discharge rate of emitter and depth of lateral are, among others, two potential factors that have more powerful impacts on the performance of SDI system. To improve fertigation efficiency, appropriate strategy of fertigation should be adopted. Changing the fertigation strategy for coarse textured soils to involve application of nutrients at the beginning of an irrigation cycle can help maintain larger amounts of solute close to and above the emitter thereby making them less susceptible to leaching losses.