柴河流域不同农田种植模式下沟渠底泥氮磷及有机质的赋存特征

Nutrients Accumulation of Ditch Sediments Under Different Planting Patterns in the Chaihe Catchment

于旱季及雨季末期对柴河流域不同农田种植模式下沟渠底泥进行原位采集,分析了沟渠底泥中养分含量变化特征及影响养分变化的主要因素。结果表明:除有效磷外,沟渠底泥有机质、全氮、碱解氮及全磷含量均表现为大棚>蔬菜地>玉米地,说明不同农田利用及管理方式是导致沟渠底泥养分产生差异的主要因素,而沟渠水分条件及植被的变化则导致雨季前后沟渠底泥养分呈现不同的时空差异。沟渠养分的长期积累将影响沟渠湿地系统对径流污染物的去除能力。因此,优化农田种植方式及管理模式仍是滇池流域面源污染防控中最重要的内容之一。

The effect of land use, ditch vegetation and water condition on nutrients accumulation of ditch sediments under different planting patterns in the Chaihe Catchment was analyzed through in situ sampling of surface waters and sediments. The results showed that the contents of soil organic matter, total nitrogen, available nitrogen, and total phosphorus in ditch sediments followed the order： greenhouse land〉vegetable land〉corn field, suggesting that the land use and management is the main factor influencing nutrients accumulation of ditch sediments. The changes of ditch vegetation and water condition led to the nutrients difference of ditch sediments in the early and late rainy season. In addition, the long-term accumulation of nutrients in ditch sediments will consequently bring potential threats to the stability of the ditch wetland ecosystem on re-moving nonpoint source pollutants. Based on the above results, the optimization of agriculture soil planting structure and management should be the most important content in the control of agricultural nonpoint source pollutants.