"三氮"在黄土非饱和带迁移转化原位试验及数值模拟

通过黄土氮肥淋滤原位试验,对"三氮"(NH4 、NO2-、NO3-)在黄土包气带迁移转化过程进行了深入研究和数值模拟.试验结果表明,硝态氮(NO2-和NO3-)在黄土中迁移性较强,可到达地下水面.由于NO2-的毒性,它在土壤和地下水的累积具有巨大的潜在危险性.因此在研究和模拟"三氮"转化过程中,不能把NO2-仅仅看作是"三氮"转化过程的一个中间过程而忽略它在地下环境中的累积效应.模型识别验证结果表明,"三氮"模拟值与实测值吻合程度较好,可以对"三氮"在包气带中迁移转化和积累过程进行模拟和预测.

In situ experiment and numerical simulation on transportation and transformation of "Three Nitrogen" in loess unsaturated zone

On the condition of experiment in situ, the mechanism of transportation and transformation of "Three Nitrogen" in loess unsaturated zone was discussed, and the numerical simulation was carried out, too. Resultants showed that the transportation velocity of nitrate (NO~-_2 or NO~-_3) was fast, it could reach down to the water table. On account of NO~-_2 is poisonous, it has potential danger to environments and groundwater due to the accumulation of NO~-_2 in soils and groundwater. In the process of study on simulating transportation and transformation of "Three Nitrogen", we cannot just regard NO~-_2 as a intermediate of "Three Nitrogen", and ignore NO~-_2 accumulation in soils and groundwater. Moreover, the results showed that simulation results are coincident with datum from experiment, this proved that numerical simulation models established in this paper are good, reliable and can be used to simulate and predict the process of transportation and transformation about "Three Nitrogen" in the unsaturated zone.