大冲流域不同土地利用类型土壤的氮素淋溶模拟研究

Study on Nitrogen Leaching in Soils of Different Land Utilization Type in Dachong Watershed

为了解氮素在不同土地利用类型土壤中的淋溶过程,以具有代表性的、封闭的大冲流域不同土地利用类型土壤为研究对象,通过原状土柱试验,模拟806.4mm降雨量对其氮素淋溶过程的影响。结果表明:1)在不同土地利用类型土壤中,总氮、硝态氮和氨态氮淋溶总量的大小顺序分别为菜园地>坡耕地>梯平地>水稻田>杉木林地>混交林地>疏林地、菜园地>梯平地>坡耕地>疏林地>水稻田>杉木林地>混交林地和菜园地>杉木林地>疏林地>梯平地>水稻田>混交林地>坡耕地,其淋溶量的空间变异以坡耕地最大,水稻田最小。2)影响不同土地利用类型土壤氮素淋溶的因素有水解氮、全氮、自然含水量、比重、无定形铁和全钾等。结论:菜园地的氮素淋溶总量高于其他利用类型土壤,因此,在进行蔬菜种植时必须采取相应措施防止氮素淋溶损失造成水体污染。

The undisturbed soil pillars of different land utilization types from the representative and closed Dachong watershed were treated with simulated 806.4 mm rainfall to study the effect on nitrogen leaching process in soils of different land utilization types.The results showed that： 1）The leaching loss of total nitrogen,nitrate nitrogen and ammoniacal nitrogen of different land utilization types was vegetable landslope farmlandterraced fieldpaddy fieldChinese fir woodlandmixed forest landopening forest land,vegetable landterraced fieldslope farmlandopen forest landpaddy fieldChinese fir woodlandmixed forest land,and vegetable landChinese fir woodlandopen forest landterraced fieldpaddy fieldmixed forest landslope farmland respectively,and the spatial variation of their leaching loss of the slope farmland and paddy field was the maximum and minimum separately.2） The factors to affect soil nitrogen leaching of different land utilization types were hydrolysable nitrogen,total nitrogen,natural water content,specific gravity,amorphous iron,total potassium and so on.Because total soil nitrogen leaching amount of the vegetable land is higher than other land utilization types,and the corresponding measures to control soil nitrogen leaching loss should be used to prevent water contamination in the vegetable land.