不同灌水量和灌水器埋深下单坑渗灌红壤水分入渗特性及其模拟

[目的]探究灌水量和灌水器埋深对单坑渗灌红壤水分入渗特性的影响.[方法]通过室内土箱试验模拟大田单坑渗灌过程,研究了单坑渗灌红壤在不同灌水量(1、2L和3L)和不同灌水器埋深(10、15cm和20cm)条件下湿润锋运移距离、累积入渗量和土壤含水率的分布规律,并采用交替方向隐式差分法对土壤水分空间分布进行了模拟.[结果]...

Impact of Burying Depth of Emitters in Pit Irrigation on Water Infiltration in Red Soil

【Objective】Irrigation pit is a technology to collect and store water for it to be used in irrigation. The objective of this paper is to study experimentally the impact of burying depth of emitters of subsurface irrigation in combination with a pit on water infiltration in red soil.【Method】The experiment was conducted indoors using soil tanks. The moving distance of the wetting front, cumulative infiltration and spatiotemporal distribution of soil water content under different irrigation amounts from 1 to 3 L, and emitter depths from 10 to 20 cm, were measured and calculated. We then modelled soil water movement in the tanks numerically based on the Richards' equation, and fitted the infiltration process to different models.【Result】The infiltration rate increased with irrigation amount and decreased as the burying depth of the emitters increased. The infiltration rate declined as the time elapsed. In the first 540 min after onset of the experiment, the wetted area and the maximum moving distance of the wetting front increased with irrigation amount, thereby driving the water moving towards the bottom-right of the tanks. The maximum moving distance of the wetting front in the vertical direction was greater than that in the horizontal direction; the influence of irrigation amount on soil water content was greater than the impact of the emitter depth.【Conclusion】The Kostiakov model was more accurate than the Philip model to describe the water infiltration, and the numerical model can simulate spatiotemporal dynamics of the water in the soil tanks.