典型红壤旱地硝态氮水平运移规律的研究

Study on Horizontal Transport of Nitrate-N in Dry Land of Representative Red Soil

用水分扩散装置测定了湖南祁阳低山丘陵红壤4个自然发生层土壤NO3--N的含量及水平运移状况,结果表明:硝态氮水平运移速率随土壤含水量增加而相应增加,呈指数曲线变化;随运移距离增加而迅速减小,呈幂函数曲线变化。硝态氮水平运移速率与运移距离均有很好的相关性。硝态氮水平运移浓度与土壤含水量密切相关,随含水量的增加而减少,并呈幂函数曲线变化。硝态氮水平运移浓度还受到土壤水分扩散率的影响,随土壤水扩散率的升高而下降,并呈对数曲线变化。硝态氮浓度最大值均出现在湿润锋(土壤干湿交界面)上。

Horizontal migration and content of NO3^--N in four natural occurring layers of the Red soil in the hills of Qiyang, Hunan province were measured by water diffusion device. The results were as follows： the transport velocities of nitrate-N was increased with the soil moisture content, presenting typical index relation; while it decreased rapidly with transport distance of nitrate-N, presenting power relation. There was a significant relationship between the horizontal transport velocity of nitrate-N and the distance of the tracer source. Nitrate-N transport concentration decreased with increase of the soil moisture content, presenting power curve. The transport concentration was also influenced by the soil moisture diffusivity, and decreased with increase of the diffusivity, presenting logarithmic curve. Transport concentration of Nitrate-N reached maximum value at the surface of wet spearhead, which existing on the interface beween wet and dry soil.