西北农区不同盐分分布下适宜淋洗定额研究

Study on the Leaching Quota of Saline⁃Alkaline Soil Under Different Salt Distribution in Agricultural Areas of Northwest China

为了探究不同土壤初始盐分含量及分布特征条件下的淋洗定额,通过室内土柱试验,在100~500 mm范围内,采用两相邻差为20 mm的淋洗定额进行模拟淋洗,研究不同淋洗定额对土壤水盐运移的影响,分析不同初始条件下土壤盐分淋洗特征和淋洗效率,确定适宜的淋洗定额。结果表明:土壤盐分均匀分布和非均匀分布情况下,淋洗效率P随淋洗定额的增大呈现出先急速上升、后缓慢上升、最后逐渐下降的趋势;使土壤盐分达到脱盐目标的淋洗定额均小于淋洗效率P峰值所对应的淋洗定额。应根据研究区不同初始盐分分布情况和水资源情况,选择适宜的淋洗定额以满足脱盐要求,从而实现对盐碱土的高效节水淋洗。

In order to explore suitable leaching quota under different initial conditions of soil salinity and distribution characteristics,this study employed a laboratory simulation experiment to simulate the effect of leaching quota with two phase adjacent difference of 20 mm in the range of 100-500 mm on soil water and salinity transport.The suitable leaching quota was thus attained based on the characteristics and effi⁃ciency of soil salinity leaching under different initial conditions.The results demonstrate that the leaching efficiency P shows a trend of rapid increase,then slow increase and finally gradual decrease with the increase of leaching quota under uniform and non⁃uniform distribution of soil salt.The leaching quota of soil salinity to reach the goal of desalination is less than that the leaching quota corresponding to the peak val⁃ue of leaching water efficiency P.Appropriate leaching quota under different initial conditions can realize efficient water⁃saving leaching of sa⁃line and alkaline soil,which is of great significance to the improvement of saline and alkaline land and water⁃saving in arid areas.