Characteristics of Nitrogen and Phosphorus Migration in Red Soil Sloping Farmland after Fertilization under In-termittent Rainfall
In order to explore the sustained migration characteristics of nitrogen and phosphorus in fertilized red soil slope farmland under intermittent rainfall,eight events of indoor artificial rainfall simulation experiments were conducted inter-mittently from July to August 2022 to observe the changes in concentration and flux of nitrogen and phosphorus,and to an-alyze the first flush effect(FFE)of different forms of nitrogen and phosphorus in runoff.The results show that:(1)If the whole intermittent rainfall experiment is regarded as a complete rainfall cycle,the cumulative loss of nitrogen in interflow is greater than that in surface runoff,while the loss of phosphorus is mainly due to surface runoff.There is a significant corre-lation between the cumulative loss of nitrogen and phosphorus from surface runoff and interflow.The exponential or loga-rithmic function can be used to fit the relationship between the cumulative nitrogen/phosphorus loss and the cumulative production flow.(2)Under the condition of intermittent rainfall,the first flush phenomenon of nitrogen and phosphorus in fertilized red soil slope farmland occurred.The intensity of FFE varied as TDP＞TP＞TPP＞NH4+-N＞TN＞NO3-N.(3)The emigration of NH4+-N,TP,TDP and TPP was mainly concentrated in the first three rainfall events,and their concentra-tions in surface runoff were always greater than that in interflow,and their intensity of FFE in interflow was slightly higher than that in surface runoff.In contrast,the migration of NO3--N and TN with runoff exhibits a high concentration in surface runoff during early intermittent rainfall and a high concentration in interflow during later stages,and the first flush phenom-enon of NO3--N and TN in surface runoff is more significant.The above results indicate that,the effective ways to prevent and control non-point source pollution of fertilized red soil slope farmland in South China are:(1)to control the loss of ni-trogen and phosphorus in surface runoff and interflow in early rainfall events and(2)to pay attention to the long-term and sustained loss of nitrogen in interflow.
red soilintermittent rainfallsurface runoffinterflownitrogen and phosphorus migrationfirst flush effect
万方数据
维普
