多点源滴灌条件下土壤水分运移模拟试验研究

为了指导密植作物的滴灌系统合理设计，通过室内物理试验模拟了多点源滴灌条件下土壤水分运移过程，重点研究了不同滴头流量下交汇湿润体内的土壤水分时空动态分布规律．多点源滴灌条件下土壤水分运动遵循先点源入渗、再湿润锋交汇和最后形成湿润带的规律．灌水结束时，土壤水分分布呈现湿润体上部复杂、下部相对简单的特征．湿润体上部，在滴头下方存在土壤含水率相对较高的区域，2个滴头之间近地表处存在土壤含水率相对较低的区域；湿润体下部同一深度土层上的含水率有趋于一致的趋势．灌水结束后，由于土壤水分再分布，同一深度土层上含水率差异逐渐减小．灌水量相同条件下，灌水结束时，滴头流量小的入渗深度较大，湿润体内土壤平均含水率较低；灌水结束后，受土壤水分再分配的作用，不同滴头流量下入渗深度的差异较灌水结束时有所减小．

Simulation experiments on soil water movement in multiple point sources drip irrigation

In order to provide a guide to reasonable design of drip irrigation system for close-grown crops, soil water movement in drip irrigation of multiple point sources was simulated by indoor physical experiment. The spatial-temporal dynamic distribution of soil water was mainly studied under different emitter discharge rates. There were three stages in the infiltration, namely, point source infiltration, overlapped wetting front and wetting belt. The characters of soil water distribution were complex in the upper zone and relatively simple in the lower zone in the wetted volume. In the upper zone of wetted vo- lume, there was a region with higher soil water content under the emitter and a zone with lower water content near the surface between two emitters. The soil water content tended to be uniform on the same layer in the lower zone of wetted volume. After the end of irrigation, difference in water content on the same layer in the wetted soil was decreased due to soil water redistribution. Compared to a higher emitter discharge, the infiltration depth was deeper and the average soil water content was lower at a smaller discharge at the end of irrigation for the same irrigation amount. After the irrigation was completed, the difference in infiltration depth was slight for different emitter discharges due to soil water redistribution.