黄淮海平原主要土类中硝态氮水平运移规律

Horizontal Transport of Nitrate in Main Soil Groups of Huang-Huai-Hai Plain

对黄淮海平原的主要土壤类型 (黄潮土和风沙土 )中硝态氮水平运移规律进行了研究 .结果表明 :硝态氮水平运移速率随供试示踪剂源的距离增加而迅速减小 ,其变化趋势呈幂函数关系 .由于各土层的土壤性质不同 ,所以硝态氮的运移曲线发生差异 ,但总的趋势是离示踪剂源 2 0cm距离内 ,硝态氮的水平运移速率主要由硝态氮的浓度梯度和水势梯度控制 ,而在 2 0cm以后趋于平稳 ,则主要由土壤的基质势起作用 .硝态氮水平运移速率随土壤含水量的增大而升高 ,并呈指数曲线变化 .硝态氮水平运移的浓度受非饱和土壤水扩散率的影响 。

The horizontal transport of nitrate in main soil groups (yellow fluvo\|aquic soils and aeolian sandy soil) in Huang\|Huai\|Hai Plain was studied. The results were as follows: the horizontal transport velocity of nitrate decreased with the distance of the tracer source in power function. Due to different soil property in soil profile, the curves of horizontal transport of nitrate were difference. The horizontal transport velocity of nitrate was controlled by the concentration gradient and soil water potential gradient in 20 cm of horizontal soil column. It was stable after 20 cm, which was controlled by soil matric potential. The horizontal transport velocity of nitrate was in a sharp positive relation with the soil moisture content and changed with exponential function. The concentration of nitrate in horizontal transport decreased with the unsaturated soil water diffusivity increased and changed with logarithmic function.