Study on Dynamic Characteristics of Nitrogen in Surface Water of Paddy Field by Equal Nitrogen Organic Substitution
To prevent and control the loss of nitrogen runoff in paddy fields in plateau lake basins and protect the ecological environment of receiving water bodies,under the paddy-upland rotation planting pattern in Erhai Lake Basin,four equal nitrogen organic substitution treatments were set up,including no fertilization(CK),single application of chemical fertilizer(NPK),combined application of organic and inorganic fertilizers(NPKS),and total replacement of organic fertilizer(SS).The dynamic changes of nitrogen concentration in surface water of paddy field were studied,and the effect of organic fertilizer instead of chemical fertilizer on nitrogen loss in surface water was discussed.The results showed that the concentrations of NH4+-N,NO3--N,Org-N and TN in surface water increased rapidly after the application of base fertilizer,and reached the peak within 3-7 days.7 days after fertilization was the key risk period to prevent the loss of nitrogen in surface water.The proportion of NH4+-N/TN concentration in surface water was 39.01％-54.01％,the proportion of NO3--N/TN concentration was 11.33％-21.62％,and the proportion of Org-N/TN concentration was 33.85％-41.94％.The application of chemical fertilizer nitrogen increased the proportion of NH4+-N/TN concentration in surface water,and the application of organic fertilizer increased the proportion of NO3-N/TN and Org-N/TN concentration in surface water.The response of organic substitution of equal nitrogen amount to nitrogen concentration in surface water decreased with the increase of fertilization days.The concentration changes of NH4+-N,NO3--N,Org-N and TN in surface water decreased in a quadratic polynomial,and the nitrogen concentration in surface water tended to be stable at a low level after 35-40 days of nitrogen application.Among the three organic substitution planting methods,NPKS treatment could reduce the nitrogen concentration in surface water and reduce the risk of nitrogen loss in paddy fields.
equal nitrogenorganic substitutionpaddy-upland rotationsurface water of the paddy fieldnitrogen loss
万方数据
维普
