集约化种植条件下土壤硝态氮动态变化及累积特征研究

Characteristics of Soil Nitrate Nitrogen Dynamic Variations and Accumulation Under Intensive Planting

选取江阴市沿江平原地区的3种典型农业种植区,即大棚葡萄集约化种植基地、蔬菜集约化种植基地和常规种植农田为研究对象,通过田间现场采样分析的方法研究了不同种植方式下土壤剖面硝态氮含量的动态变化和累积特征。结果表明,葡萄种植基地0—100cm各土层硝态氮含量随时间的变化波动较大,而蔬菜种植基地和常规种植农田的表层土壤硝态氮含量变化幅度大于深层土壤;3种典型种植区的土壤硝态氮含量均呈现随着土层深度的增加而逐渐减小的趋势,其中土壤硝态氮含量最大值出现在葡萄种植基地的20—40cm土层中;葡萄种植基地各土层硝态氮平均累积量均高于蔬菜种植基地和常规种植农田,大棚葡萄集约化种植基地0—100cm土层硝态氮平均累积总量高达400.96kg/hm2,显著高于蔬菜集约化种植基地和常规种植农田的累积总量,这进一步表明不合理过量追肥导致土壤中硝态氮大量累积,增大了氮素淋失和地下水环境污染的风险。

Three typical agricultural planting areas in riparian plain of Jiangyin City, i. e. , greenhouse vine in- tensive planting base, vegetable intensive planting base, and general planting farmland, were selected as re- search objects and dynamic changes of soil nitrate nitrogen content under different planting patterns were studied by the experimental method of field sampling analysis. Results indicated that the variation of nitrate nitrogen content in vine planting base fluctuated greatly with time. However, the variation amplitude of ni- trate nitrogen content in surface soil was greater than that in deep soil layer in vegetable intensive planting base and general planting farmland. Nitrate nitrogen content in three typical planting areas showed a de- creased tendency with the depth of soil profile, including the maximum of soil nitrate nitrogen content appearing in the 20--40 cm layer in vine planting base. The average accumulation of nitrate nitrogen in every soil layer in vine planting base was higher than that in vegetable intensive planting base and general planting farmland. The average accumulation of nitrate nitrogen in the 0--100 cm soil layer in greenhouse vine intensive planting base was up to 400. 96 kg/hmz, which was significantly higher than that in vegetable intensive planting base and general planting farmland. This indicated that unreasonable excessive fertilization let to nitrate nitrogen accumulation in the soil profile and increased the risk of nitrogen leaching loss and groundwater environmental pollution.