淮北平原区沟渠控制排水与不同植被覆盖条件下农田氮磷流失特征分析

Analysis of nitrogen and phosphorus loss characteristics of farmland under ditch controlled drainage and different vegetation coverage conditions in Huaibei Plain

为综合分析沟渠控制排水与植被覆盖对淮北平原典型农田氮磷流失变化的影响,充分发挥农田沟渠生态服务功能和环境效益。本文以利辛试验区不同沟渠断面的氮磷观测点数据为依据,分析沟渠氮磷养分流失特征规律。研究表明:控制排水期间车辙大沟春店闸下游断面TN、NO_(3)^(-)-N浓度分别较闸上游减少24.3%、19.7%,闸上TP浓度较闸下虽未显著降低,但随时间变化动态波动表现放缓。控制排水条件下的排水沟渠中TN和NO_(3)^(-)-N浓度变化对植被盖度高低有更显著的响应关系,植被生长状态较植被覆盖度对TP流失有更好的吸收拦蓄作用。因此,通过在淮北平原大沟采取控制排水措施能够有效减少农田氮素向下游流失,并能促进植物对氮、磷的吸收拦蓄作用。

To comprehensively analyze the impact of the coupling effect of controlled drainage in ditches and vegetative cover on the changes in nitrogen and phosphorus loss in typical farmland in the Huaihe River Plain,and fully leverage the ecological service functions and environmental benefits of farmland ditches and channels.Based on the nitrogen and phosphorus observation data from different sections of ditches in the Lixin experimental area,this study analyzed the characteristics and patterns of nitrogen and phosphorus nutrient loss in the ditches.The results showed that the concentrations of TN and NO_(3)^(-)-N in the downstream of the Chundian gate in Chezhe ditch were 24.3%and 19.7%lower than those in the upstream of the gate during the controlled drainage period.Although the TP concentration on the gate was not significantly lower than that under the gate,the dynamic fluctuation with time was reduced.The changes of TN and NO_(3)^(-)-N concentrations in the drainage ditches under controlled drainage conditions had a more significant response to the vegetation coverage,and the vegetation growth state had a better absorption and retention effect on TP loss than vegetation coverage.By taking drainage control measures in Huaibei Plain,it can effectively reduce the loss of nitrogen from farmland to downstream,and promote the absorption and storage of nitrogen and phosphorus by plants.