Discussion On The Soil Water Characteristic Curve And Nitrogen Distribution Of The Agricultural Soil In Shunyi Of Beijing

Application of nitrogen fertilizer is an important means of improving crop yields, however, a large number of application of fertilizers in increasing crop yields but also increased the risk of the environment inevitably leads to a large number of crop uptake of nitrogen has not been left in the soil, thus polluting surface, groundwater bodies and the atmosphere such as the ecological environment. This paper selected a typical soil as a research object in Shunyi district of Beijingi, and focus on the moisture characteristic curve measurement and analysis of experiments with different rainfall conditions, fertilization of winter wheat and summer maize farmland soil nitrogen distribution of the field trials.To achieve the following main results:(1)Soil water content and the corresponding value of tension are obtained using centrifuges and was simulated by VG and BC mode1 of soil samples from Shunyi in Beijing.According to the data tested by the parameters of the field soil physical properties,the charateristic of the soil monisture curve have been compared under the differerdtexture,plante condition and differend depths. The result show that the soil texture and cultivation conditions have a significant impact on the soil moisture characteristic curve of the undisturbed soil.(2)Carried out by simulated rainfall field experiment to study the different levels of rainfall and fertilization on soil nitrate distribution of maize, the cumulative amount of impact in Shunyi, Beijing.The results showed that when soil conditions are the same soil nitrate-N concentration and intensity of rainfall, the amount of nitrogen, nitrate-N concentration increases with increasing rainfall intensity; with the nitrogen application rate increased, levels of soil nitrate-N concentration Jun Cheng is also the rising trend.(3) Through the corn fields typical of the conduct of the whole growth period Shunyi District of Beijing, nitrogen determination of nitrogen in soil infiltration of the wetting front as the growing season rainfall continue to lower, in the summer and early growth of corn nitrate are mainly distributed in 0-60cm soil, the cumulative peak at 20cm Branch; jointing stage of artificial fertilization heavy rainfall, the North district in the 40mm/h to reach peak intensity of the accumulation of 35.1cm, the South district in the 70mm/h rainfall intensity moved to 67.1cm. To summer maize harvest, the two are able to reach the quarters of the accumulation peak at 140cm and have trickle-down trend. Nitrogen will further infiltration of groundwater pollution.