太湖地区主要水稻土中硝态氮水平运移规律的研究

Horizontal Transport of Nitrate Nitroge in Main Paddy Soil of Tai Lake Area

对太湖地区主要水稻土乌栅土中硝态氮水平运移规律的研究结果表明 :硝态氮的浓度随供试示踪剂源距离的增加而减小 ,其变化趋势呈对数曲线关系。硝态氮水平运移过程中 ,硝态氮浓度与含水量有密切的关系 ,硝态氮浓度随土壤含水量的增加而成比例增加 ,呈指数曲线关系。硝态氮的运移速率与运移距离有很好的相关性 ,并呈幂函数关系。从供试的示踪剂源开始到距离 2 0 cm时 ,硝态氮的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 0 cm以后 ,则趋于平稳 ,这时主要由土壤的基质势起作用。

The nitrate nitroge horizontal transport of mainly paddy soil(Wushan soil) in Tai Lake area was studied. The results were as follows: The concentration of nitrate nitroge in horizontal transport decreased with the increasing distance of the tracer source and changed with logarithm function. The transport concentration of the nitrate nitroge was in a sharp positive relation with the soil moisture content and changed with exponential function. The horizontal transport velocity of nitrate nitroge was significant relation with the distance of the tracer source in power function. Therefore, the velocity of nitrate nitroge horizontal transport was controlled both by the concentration gradient and soil water potential gradient from begin to 20 cm in horizontal soil column. It was stable after 20 cm, which was controlled by soil matric potential.