| In order to grasp the characteristics of spatial distribution of nutrients in farmland topsoil,this paper takes Xinjiang Shawan County as the research area,the Shawan County is divided into four regions,namely mountainous area,mountain front area,plain area,desert Fringe region,using ARC GIS software and traditional mathematical statistics method,analysis of the topsoil pH value,organic matter,total nitrogen,available phosphorus,available potassium,as well as available microelement of spatial distribution characteristics.At the same time,the influence of drip irrigation under membrane on the vertical distribution of soil salinity and nutrients was analyzed with cotton field as the main research object.The results indicated that:(1)Basic statistics of topsoil nutrient in farmlands layer in Shawan CountyThe average soil pH value of Shawan County farmland topsoil(0～20 cm)was 8.20,the mean value of soil organic matter and total nitrogen was 14.53 g/kg,0.31 g/kg,respectively,at low level,and the average content of soil available phosphorus and available potassium was 14.42 mg/kg,192 mg/kg,respectively,at a high level,the average soil available Fe,available Mn,available Cu and available B content are 12.28 mg/kg,11.22 mg/kg,1.74 mg/kg and 1.42 mg/kg,respectively,at a high level,and the average soil available Zn content is 1.15 mg/kg at the intermediate level.(2)Topsoil nutrient spatial layout of farmlands layer in Shawan CountyThe topsoil organic matter and total nitrogen in the farmland ploughing layer in Shawan County showed low content in the central plain area,high content in mountainous and desert fringe areas,high available potassium,available B as the anterior region of the central mountain,the content of the plain area,the low content of mountainous and desert marginal areas,and the decrease of available phosphorus and available Mn in the southwest to northeast,available Zn is shown to rise in the southwest to the northeast.(3)Vertical distribution characteristics of soil salt and nutrient in drip irrigation cotton field under plastic film in Shawan CountyThe soil pH and salt content of drip irrigation in cotton field under Shawan County film has obvious increasing trend under 0～100 cm soil layer,and the salinity accumulation phenomenon occurs in 80～100 cm soil layer.Soil organic matter,total nitrogen and available nutrient showed a significant decline from the surface,in which the content of organic matter,total nitrogen and available nitrogen was higher in 0～20 cm soil layer,and the content of available phosphorus and available potassium was accumulated in 0～40 cm soil layer.Therefore,in the management of farmland soil in Xinjiang,we should pay attention to the salt monitoring and salt discharge of the bottom soil layer,increase the application of organic fertilizer and reduce the amount of phosphate fertilizer,implement zoning and targeted fertilization according to the spatial distribution and grading characteristics of nutrients,promote soil nutrient balance,and provide balanced soil fertility for crop production.The results of this study on rational management of soil nutrients in farmland in arid areas are of great significance,and provides basic data and scientific basis for crop weight loss efficiency and soil quality improvement. |
