下衬阻水板宽度对地下滴灌土壤水分运移的影响

【目的】提高深埋地下滴灌在作物生长初期的水分供应能力,降低其深层渗漏风险。【方法】设置无阻水板、下衬7.8 cm阻水板及9.4 cm阻水板的点源地下滴灌土槽试验,测定下衬阻水板宽度对地下滴灌土壤湿润锋运移和土壤水分分布的影响程度。【结果】下衬阻水板不影响地下滴灌土壤湿润锋形状,仍近似于扁椭圆形,但改变了地下滴灌土壤湿润模式;下衬阻水板对地下滴灌土壤水分水平方向运移距离影响不大,但明显增加了土壤水分垂直向上运移距离,减小了土壤水分垂直向下运移距离,使得地下滴灌土壤湿润体整体向上层迁移,阻水板越宽,土壤湿润体向上层迁移的越明显。下衬阻水板可以调整土壤湿润体内的土壤水分分布,随着下衬阻水板宽度的增大,浅层(0~10 cm土层)土壤含水率增大,而深层(50~60 cm土层)土壤含水率减小。【结论】下衬阻水板可以促进地下滴灌土壤湿润体及水分向上层土壤集中,有利于保障作物生长初期的水分供应。

Effect of Underlying Water-blocking Plate Width on Soil Moisture Movement under Subsurface Drip Irrigation

【Objective】This study is to improve the water supply capacity of deep buried subsurface drip irrigation in the early stage of crop growth, and reduce the risk of deep percolation.【Method】In this paper, the soil-bin tested under point-source subsurface drip irrigation with three experiment treatments,which were underlying water-blocking plate with 7.8 cm width and 9.4 cm width, and without water-blocking plate. It was to determine the effect of underlying water-blocking plate width on the movement of soil wetting front and soil moisture distribution.【Result】The underlying water-blocking plate did not affect the shape of soil wetting front, which was still similar to the flat oval, but it changed the soil wetting pattern. The underlying water-blocking plate had little effect on the horizontal migration distance, but it obviously increased the vertical upward migration distance and reduced the vertical downward migration distance of soil moisture, making the wetted soil volume migrate to the upper layer of soil as a whole, and the wider the water-blocking plate, the more obvious the migration of the wetted soil volume. Meanwhile, the underlying water-blocking plate can adjust the soil moisture distribution in the wetted soil volume. When the underlying water-blocking plate was broadening, the soil moisture content of the shallow soil(0~10 cm) increased, while it was reduced in the deep soil(50~60 cm).【Conclusion】The underlying water-blocking plate can promote the wetted soil volume and soil moisture to concentrating on the upper layer of soil under subsurface drip irrigation, which is beneficial to ensure the water supply in the early stage of crop growth.