涌泉根灌湿润体水氮运移特性试验研究

在陕北米脂山地微灌枣树示范基地原状土上进行了涌泉根灌肥液入渗试验，研究了湿润体特征值的变化规律及水氮运移特性.〖JP+1〗结果表明：涌泉根灌入渗能力随肥液质量浓度增大而增大，累积入渗量与入渗时间的关系符合Kostiakov模型；竖直剖面的水平和垂直方向上的湿润锋运移速度均随肥液质量浓度增大而增大，并与时间均呈良好的幂函数关系.肥液质量浓度越大，涌泉根灌相同时间内湿润体的湿润深度越深，相同位置处的土壤质量含水率越大.清水与不同肥液质量浓度的涌泉根灌土壤平均质量含水率分布规律类似，肥液质量浓度越大，相同土层深度的质量含水率越大.在一定施肥条件下，涌泉根灌肥液入渗相同深度处NO-3-N与NH+4-N质量比均随肥液质量浓度增大而增大，经过水分再分布，均于土层深度70 cm处接近本底值.

Experiment on water and nitrogen transport characteristics of wetting body in bubbled root irrigation

In the jujube micro irrigation demonstration base on Mizhi Mountain of northern Shaanxi, infiltration experiments of fertilizer solution were carried out in undisturbed soil in bubbled root irrigation to study wetting soil body and nitrogen transport characteristics. The results showed that infiltration capacity of bubbled root irrigation increased with increasing fertilizer concentration and the relationship between cumulative infiltration and infiltration time was in accord with Kostiakov model. The vertical and horizontal migration speeds of wetting front increase with increasing fertilizer concentration, and can be expressed as a power function of time. The greater the concentration of fertilizer solution, the deeper the wetting depth of wetting body in the same time, and the higher the soil moisture in the same position. The distribution of average water content of soil water in bubbled root irrigation with different fertilizer concentrations was similar to the distribution of concentration of fresh water. The higher the concentration of fertilizer and the higher the water content in the same soil depth. Under a certain fertilization condition, the contents of NO-3-N and NH+4-N in the same infiltration depth of infused fluid by bubbled root irrigation increase with increasing concentration of fertilizer solution. After water redistribution, the contents of NO-3-N and NH+4-N in the depth of 70 cm are near their back ground values in the soil.