湖南省稻田化肥施用与氮磷流失状况的研究

Application of Chemical Fertilizer and the Loss of Nitrogen and Phosphorus in Paddy Soils in Hunan

为合理施用化肥和改善农业生态环境提供依据 ,于 1 999年调查了湖南省 1 0个县 (市 )高产稻区水稻产量和施肥情况 ,采集几种典型高产稻田 (红黄泥田、潮沙泥田和紫泥田 )耕层土样、田面水样以及受田面水影响的附近田外水样 ,分析了土样碱解氮和有效磷以及水样中的氮和磷的含量 .结果表明 :目前湖南稻田施肥以施用单质化肥为主 ,复合肥施用比例过小 .化肥施用相对较多的地区氮、磷地表流失明显 ,田面水与田外水之间氮、磷含量的相关系数分别为 0 .80 2和 0 .80 6 ,均达极显著水平 ;氮肥施用量与田面水中氮含量之间相关系数为 0 .799,亦达极显著水平 .参照水体富营养化氮、磷质量浓度临界值指标 ,稻田附近水体氮增加或磷增加或氮、磷同时增加造成水体趋向富营养化的百分率分别达 6 4% ,6 8%和 38% .认为推广平衡施肥技术 ,改善耕作制度 ,加强水肥管理 ,采用生物抑制剂等措施是减少化肥流失的实用途径 .

To provide a basis for rational application of chemical fertilizer and improve agricultural enviroment,rice output and fertilizer application in high yield rice areas in 10 counties of Hunan province were investigated in 1999.Soil samples in topsoil,surface water samples in paddy field and drain off water samples were collected,available nitrogen and available phosphorus in soil samples and nitrogen and phosphorus were analysed.The results show that most fertilizes applied in paddy field are single chemical,not many compost fertilizers.The more chemical fertilizers are used, the more nitrogen and phosphorus are lost. The nitrogen and phosphorus between surface water of paddy soils and drain off water are relative obviously, and their coefficients are 0.802 and 0.806, respectively. The nitrogen fertilizer applied and the nitrogen in field water is relative obviously, too. The coefficient is 0.799. According to the eutrophication's critical concentration of the total nitrogen and phosphorus of surface water, 64% water around paddy fields is affected by nitrogen, 68% by phosphorus and 38% by both nitrogen and phosphorus.A practical method to reduce fertilizer loss is to popularize the technique of equilibrium application of fertilizer,improve cultivation system and management of water and fertilizer,and use biological inhibitor.