膜孔肥液多向交汇入渗土壤硝态氮运移特性试验研究

发布时间：2018-03-21 20:37

本文选题：膜孔灌　切入点：多向交汇　出处：《中国农村水利水电》2017年05期 　论文类型：期刊论文

【摘要】：通过室内试验,研究了相同供水条件下不同取土时间的土壤NO_3~--N在湿润体剖面的分布及运移特性。结果表明:在供水入渗阶段,土壤NO_3~--N浓度的最大值出现在土壤表层;土壤NO_3~--N浓度锋运移距离和最大值随时间的延长而增大。供水停止时,随着与膜孔中心距离的增加,土壤NO_3~--N含量逐渐减少;膜孔中心两侧的湿润面在土体表层12 cm范围内NO_3~--N含量变化梯度较小,湿润锋处的土壤NO_3~--N含量变化梯度较大;先交汇中心界面的NO_3~--N含量比后交汇中心界面的NO_3~--N含量稍大;土壤垂向含水率在土壤表层10 cm范围内相差较小,且分布均匀;在10 cm以下变化梯度较大,各中心垂向土壤含水率的变化梯度为:abDCAB;垂向土壤NO_3~--N含量在表层8 cm范围内相差较小,且分布均匀;810 cm范围内,后交汇中心ab的土壤NO_3~--N含量比AB和DC中心的稍小;10 cm以下的土壤NO_3~--N含量变化梯度为:abDCAB。进入再分布阶段,土壤NO_3~--N浓度锋运移距离随时间继续延长,湿润土体内NO_3~--N浓度的分布逐渐均匀;随时间的延长,土壤剖面NO_3~--N浓度的最大值逐渐减小,且位置逐渐向下迁移。说明对于灌水定额较小的膜孔肥液多向交汇入渗,NO_3~--N主要存在于土壤表层,对地下水造成污染的可能性较小。
[Abstract]:Through laboratory tests, the effects of soil NO_3~--N in different time under the condition of the same soil water distribution and transport characteristics of wetted section. The results showed that: in the water infiltration, soil NO_3~--N concentration reached the maximum at the surface soil; soil NO_3~--N concentration front transport distance and the maximum value increased with the time to stop water supply. When, with increasing distance from film hole center, soil NO_3~--N content decreased gradually; the wetted surface on both sides of the film hole center on the soil surface in the range of 12 cm NO_3~--N content change gradient is small and the wetting front change gradient of soil NO_3~--N content greatly; NO_3~--N content and NO_3~--N content of the intersection of the center interface than the intersection center interface slightly large; vertical soil moisture content in the soil surface in the range of 10 cm is small, and uniform distribution; larger under 10 cm gradient, the vertical soil moisture The change rate of the gradient is abDCAB; vertical soil NO_3~--N content in the surface within the range of 8 cm is small, and uniform distribution; in the range of 810 cm, after the intersection of the center of AB soil NO_3~--N content than AB and DC center slightly smaller; variation gradient of soil NO_3~--N content below 10 cm: abDCAB. into the distribution stage, the soil NO_3~--N concentration front transport distance with time to extend the distribution of NO_3~--N concentration in the wet soil body gradually uniform; with the extension of time, the maximum value of soil NO_3~--N concentration decreased gradually, and the position gradually downwards. That film hole fertilizer solution for irrigation quota small bilateral interference infiltration, NO_3~--N mainly exists in the soil the surface, the smaller the possibility of groundwater pollution caused by.

【作者单位】：兰州交通大学土木工程学院;甘肃省电力设计院;西安理工大学水资源研究所;
【基金】：国家自然科学基金项目(50579064,51479161) 兰州交通大学“青蓝”人才工程基金项目(QL-08-20A)
【分类号】：S153

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