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Effects of Water Path Flow and Evaporation on Nitrate Nitrogen Movement through Unsaturated Soil

水路流动和蒸发对硝态氮通过非饱和土壤运动的影响

基本信息

批准号：
03650448
负责人：
SAKAMOTO Yasushi
金额：
$ 1.28万
依托单位：
Yamanashi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650448/
关键词：
Groundwater Pollution Nitrate Nitrogen Unsaturated Media Water Path Flow Evaporation

项目摘要

Effects of water path flow and evaporation on nitrate nitrogen (NO_3-N) movement through unsaturated soils were investigated by experiments, computer simulations and observations of groundwater qualities.1. Temporal Changes of Groundwater QualitiesTo get some informations on NO_3-N movements in natural basins under natural weather conditions, the temporal changes of NO_3-N concentrations of groundwaters were observed. Observed results showed that (1) groundwater qualities responded to rainfall events, (2) quick responses of the qualities to the events suggested the influence of such quick flow as water path flow, and (3) the timing and magnitude of the responses were influenced by water contents of soils and rainfall amounts.2. Water Path Flow through Unsaturated MediaThe mechanisms and conditions of water path formation in unsaturated media were investigated by experiments using model porous media and by computer simulations. The results showed that (1) the water path developed fractal patterns, (2) the combined effect of capillary force and gravity determined the shape of water path, (3) the combined effect was influenced by sizes and directions of pores, and (4) the effect of rainfall amount on the water path shape was changeable.3. Nitrate Nitrogen Movement Caused by Infiltration and EvaporationNO_3-N movement caused by infiltration and evaporation were investigated by experiments using the model soil and by computer simulations. The results showed that (1) NO_3-N was less mobile than water in porous media, (2) evaporation caused NO_3-N movement toward soil surface but did not make remarkable chage of the depth of NO_3-N percolation, (3) rainfall amount influenced the depth for big particles with heavy rainfalls, and (4) NO_3-N movement toward soil surface was remarkable for small particles.

通过室内试验、计算机模拟和地下水水质观测，研究了水流和蒸发对硝态氮在非饱和土壤中运移的影响.地下水NO_3-N浓度的时间变化为了解自然气象条件下天然盆地NO_3-N的动态变化，对地下水NO_3-N浓度的时间变化进行了观测。观测结果表明：（1）地下水水质对降雨事件有响应;（2）地下水水质对降雨事件的快速响应反映了水流等快速流动的影响;（3）地下水水质响应的时间和幅度受土壤含水量和降雨量的影响.非饱和介质中的水路径流动通过模型多孔介质实验和计算机模拟，研究了非饱和介质中水路径形成的机理和条件。结果表明：（1）土壤水通道具有分形特征;（2）毛管力和重力的共同作用决定了土壤水通道的形状;（3）毛管力和重力的共同作用受孔隙大小和方向的影响;（4）降雨量对土壤水通道形状的影响是可变的.通过模型试验和计算机模拟，研究了入渗和蒸发引起的NO_3-N运移。结果表明：（1）NO_3-N在多孔介质中的移动的性小于水;（2）蒸发作用导致NO_3-N向土壤表面迁移，但对NO_3-N的入渗深度影响不显著;