南京市土壤氮和磷的分布及其土地利用效应

目的]为预测南京市未来土壤肥力变化趋势、城乡土地的综合利用规划及面源污染防控提供科学依据。方法]通过对南京市各地土壤的采样、氮磷的全量和速效态含量分析,运用ArcView、ArcMap等软件绘制了南京市土壤肥力分布图;将南京市划分为林地、水田、旱地、旱作坡地和城镇交通地5种土地利用类型,分析不同土地利用类型之间的土壤肥力差异和成因。结果]全氮、碱解氮、全磷和速效磷平均含量分别为1.46 g/kg、113.50 mg/kg、0.69 g/kg和26.64 mg/kg,变异系数分别为52.10%、61.79%、54.35%和155.20%。南京市土壤全氮、碱解氮含量分布状况基本一致,浦口、江宁等地区土壤全氮和碱解氮含量较高,长江两岸地区土壤全磷和速效磷含量较高。结论]土壤施肥情况和管理模式对土壤肥力变化起决定作用,林地受人为干扰最小,旱作坡地有效磷丰富。沿江地区的磷面源污染值得关注。

Soil Nitrogen and Phosphorus Distribution and Its Land Use Effect in Nanjing

Objective ] The research aimed to provide the scientific basis for the forecast of the variation trend of soil fertility in Nanjing City, the comprehensive utilization planning of urban and rural land, and the prevention and control of non-point source pollution. Method ] Total content and available content of nitrogen and phosphorus of Nanjing soil samples were tested after sampling, and the map of Nanjing soil fertili- ty distribution was made by ArcView and AreMap. 5 kinds of land use types such as forest land, paddy, dry land, dry slop land and traffic land were divided. The differences and causes among different land use types of soil fertilities were analyzed. E Result ] average contents of to- tal nitrogen, available nitrogen, total phosphorus and available phosphorus were 1.46 g/kg, 113.50 mg/kg, 0.69 g/kg and 26.64 mg/kg, and variation coefficients were 52.10%, 61.79%, 54.35% and 155.20%, respectively. The total nitrogen distribution was almost consistent with available nitrogen, both of which were high in Pukou and Jiangning District. The total phosphorus and available phosphorus content were high at both sides of Changjiang River. Conclusion] The fertilization condition and management mode played a key role in the change of soil fertility. Forest land disturbed least, and abundant available phosphorus existed in dry slope land, which deserved attention about non-point pollution in river side area.