肥液浓度对浑水膜孔灌多点源入渗水氮运移的影响

为了探究浑水膜孔灌多点源入渗多向交汇下水氮运移特性,利用浑水膜孔灌入渗装置进行了室内试验,研究了不同肥液浓度(0,1,2,3,4 g/L)的硝酸铵钙溶液对浑水膜孔灌多向交汇入渗规律、单向交汇和多向交汇发生时间、膜孔中心和各交汇点(植株交汇中心、行间交汇中心和4点源交汇中心)垂直方向的含水率和NO_3~-—N的分布规律等的影响。结果表明:各肥液浓度下膜孔单位面积累积入渗量与入渗时间呈幂函数关系,入渗参数a随肥液浓度的增大而减小,入渗参数b随肥液浓度的增大而增大;随着肥液浓度的增加,单向交汇和多向交汇发生时间均提前;10 cm土层深度处,肥液入渗各中心含水率较0 g/L处理分别增加10.42%,13.94%,16.38%,24.74%;各中心垂直方向含水率随土壤深度呈现不同的变化规律;NO_3~-—N在土壤上层分布均匀,而在湿润锋处出现峰值;4点源交汇中心处NO_3~-—N含量高于其他3个中心。研究结果可为浑水膜孔灌的技术研究奠定科学基础。

Effect of Fertilizer Concentration on Water and Nitrogen Migration in Multi-point Source Infiltration of Muddy Water Film Hole Irrigation

In order to investigate the characteristics of water and nitrogen migration under multi-point source infiltration in the muddy water-filled membrane hole irrigation, the indoor hydrophobic membrane hole infiltration device was used to test the influence of the infiltration solution (0 g/L, 1 g/L, 2 g/L, 3 g/L, and 4 g/L ammonium nitrate solution) on the infiltration laws, the occurrence time of one-way intersections and multi-directional intersections, the water content in the vertical direction of film hole centers and junctions (the plant intersection center, the inter-row intersection, and the 4-point source intersection),and the distribution law of NO₃^--N. The results showed that the cumulative infiltration and permeation time per unit area of membrane pores showed a power function relationship, the infiltration index a decreased with the increase of fertilizer concentration while the infiltration index b increased with the increase of fertilizer concentration. With the increase of fertilizer concentration, the occurrence time of one-way intersection and multi-directional intersection was advanced. At the depth of 10 cm soil, the water content of each center increased by 10.42%, 13.94%, 16.38%, and 24.74%, respectively, compared with 0 g/L treatment. The water content in each center varied with the increment of soil depth. NO₃^--N was evenly distributed in the upper layer of the soil, and showed peak at the wet front. The NO₃^--N content at the 4-poing source intersection center was higher than the other 3centers.The results provide a basis for improving the theory of water-filled membrane hole irrigation.