Study On The Influence Of Mining Subsidence On Soil NPK Pool Disturbance

Nitrogen,phosphorus and potassium in the soil are important elements that make up the living body and nutrients necessary for plant growth.The abundance of the content affects the basic biogeochemical cycle and the normal life activities of the plant.During the coal mining process,various environmental factors in the mining area will be affected to varying degrees,especially in the farmland soil.In order to clarify the disturbance effect of coal mining subsidence on farmland soil nitrogen,phosphorus and potassium reservoirs,this paper takes the farmland soil in the coal mining subsidence area of Jiuli Mine in Xuzhou City as the research object,and quantitatively analyzes the soil physical and chemical properties of the farmland in the coal mining subsidence area through field sampling and laboratory experiments.The basic statistical characteristics,and the spatial distribution characteristics of soil nitrogen,phosphorus and potassium density in the subsidence area were analyzed according to the principle of geostatistics.Finally,according to the differences among the nitrogen,phosphorus and potassium reservoirs in the farmland in the study area under the influence of coal mining subsidence and without the influence of coal mining subsidence,the influence of coal mining subsidence on the soil nitrogen,phosphorus and potassium reservoirs can be obtained.In addition,the distance between sampling points and cracks,crack width,crack depth and slope subsidence factor were selected for path analysis in this study.The main conclusions are as follows:(1)Soil clay,sand and total nitrogen show strong variability,while other indexes show moderate variability;The contents of total nitrogen,total phosphorus and total potassium in the soil were different from the average values of xuzhou city and jiangsu province.(2)The soil total nitrogen,total phosphorus and total potassium density C0/C0+C in the subsidence area are less than 25%,and have strong spatial autocorrelation.The spatial variability is mainly controlled by structural factors.With the increase of soil depth,the spatial variability of soil total nitrogen and total potassium density is weakened,while the soil total phosphorus density is enhanced.(3)According to the precision evaluation results,the determination coefficients of the measured and predicted values of total nitrogen density,total phosphorus density and total potassium density at verification points are all greater than the minimum value of 0.5,RMSE values are close to zero,and kriging interpolation accuracy is high.(4)Coal mining subsidence has a great influence on the disturbance of farmland soil nitrogen pool and potassium pool in the study area,followed by phosphorus pool.Among them,the soil nitrogen pool and the deep soil potassium pool belong to the loss effect,and the soil phosphorus pool and the surface soil potassium pool belong to the surplus effect.(5)The distance between the sampling point and the crack in the coal mining subsidence area,the width and depth of the crack,and the slope of the sampling point are the main factors affecting the total nitrogen,total phosphorus and total potassium content of the farmland soil.Due to the existence of errors,more factors should be considered for more detailed studies in the future.