农田氮流失与农业非点源污染

随着氮肥的过量施用,农田氮流失容易造成农业非点源污染.农业非点源污染是农业环境富营养化的主要原因之一,改变了农业环境的生态结构与功能,造成很大危害.农田氮流失主要通过地表径流、农田排水和淋溶途径进入水体形成农业非点源污染,降雨状况、土壤特性、施肥状况、农业土地利用/土地覆盖和田间管理方式等因素与农田氮流失有密切关系.通过农田管理制度或立法、农田氮流失的源头控制和农田氮流失的扩散途径,可以实现对农业非点源污染的调控,降低施用化肥的环境风险.

NITROGEN LOSSES FROM FARMLAND AND AGRICULTURAL NON-POINT SOURCE POLLUTION

Originally, the research on the nitrogen in the agricultural ecosystems was emphasized particularly on how to increase agricultural production by making use of nitrogen fertilizer more efficiently. Recently the emphasis has been concerned with the environmental effects of nitrogen losses from farmland. Agricultural non-point source (AGNPS) pollution due to wide application of nitrogen fertilizer is becoming one of the major sources of eutrophication of agricultural environment and it changes the structure and function of agricultural ecological environment, which produces great harm. Nitrogen lost from farmland can be taken into water bodies by three main pathways, namely: runoff, drainage and leaching. They are influenced by the factors including precipitation, soil properties, fertilizer application and farmland use/land cover etc. Meanwhile, much research has been carried in the field of the management and control of AGNPS pollution, which involves farmland management regulation or legislation, source control strategies and transport control strategies. By control and regulation of AGNPS pollution, the risk of environment pollution due to nitrogen fertilizer application would be decreased.