人为干扰对闽江河口湿地土壤硝化-反硝化潜力的影响

选择闽江河口芦苇湿地为研究对象,研究了人为干扰活动(养殖塘、污染物排放和农业活动)对湿地土壤硝化-反硝化潜力的影响.结果表明,人类干扰活动对湿地土壤硝化和反硝化潜力均具有显著影响,4种土壤的硝化潜力表现为水稻田>养殖塘>排污闸口>芦苇湿地,其最大硝化率分别为103.45%、99.38%、12.58%和4.16%,而反硝化作用的变化规律则与之相反,24d内的最大反硝化率分别为21.89%、26.95%、78.15%和88.28%,说明人类干扰和管理程度越大,土壤硝化潜力越大,反硝化潜力越弱.土壤NO3--N含量是闽江河口地区不同人为干扰方式下土壤硝化-反硝化作用差异的重要指示指标,土壤pH值与土壤硝化-反硝化作用也具有密切关系,而土壤有机质、全氮、全磷和可溶性碳含量以及电导率等则与土壤硝化-反硝化作用不具有显著的相关关系.人类干扰活动导致土壤硝化能力的提高,反硝化能力的降低,能够增加土壤氮素以硝态氮形式淋失的风险.

Effects of human disturbance on nitrification and denitrification potential in the Min River estuarine wetland

The reed wetland in the Min River estuary was chosen as study object, and the effects of human disturbance (aquaculture pond, pollutant discharge and agricultural activity) on nitrification and denitrification potential in the wetland soil were measured. The nitrification and denitrification potential in the wetland soils were significantly affected by human disturbance, the nitrification potential ranked from highest to lowest as: paddy soil>aquaculture pond sediment>soil near discharge outlet>reed wetland soil, the maximum nitration ratio was 103.45%, 99.38%, 12.58% and 4.16%, respectively, while the order of dentrification potential in the four soils were opposite, the maximum denitrification ratio was 21.89%, 26.95%, 78.15% and 88.28%, respectively. The greater the human disturbance, the stronger the nitrificaiton potential, and the weaker the denitrification potential. The NO3--N contents were important indicator for the difference of nitrification and denitrification potential in soils under different human disturbance. The soil pH were significantly related to the nitrification and denitrification, while the contents of soil organic matter, total nitrogen, total phosphorus and dissolved organic carbon and electric conductivity did not show significant correlation with the nitrification and denitrification. The increase of nitrification potential and decrease of denitrification potential induced by human disturbance can increase the risk of nitrate nitrogen leaching in the Min River estuary.