| In this paper,Wangzhuang Coal Mine in Changzhi is selected as the research area.Three groups of sample plots are set up:unstable settlement area(1 year from mining time,area is about 5.5 hectares),stable settlement area(12 years from mining time,area is about 9 hectares),control area(adjacent area,not affected by mining activities,area is about 7 hectares),The physical properties of 248 soil samples were collected from 10-20cm,and the South CASS RTK equipment was used to map the terrain of three sample areas to obtain the terrain factors,study the soil physical and chemical changes in the subsidence area,and explore the changes of physical and chemical properties in each area under the background of coal mining disturbance as well as the spatial autocorrelation changes of terrain factors and soil physical and chemical properties,This paper attempts to explain the influence mechanism of terrain factors on soil physical and chemical properties.It provides theoretical support for better land reclamation and ecological reconstruction in mining area.The conclusions are as follows1 The results show that the water content of the unstable settlement area is 16.22%,the bulk density is 1.04g/cm3,the unstable settlement area is 0-10cm,organic matter is 5.54g/kg,available nitrogen is 43.16mg/kg available phosphorus is 39.54mg/kg available potassium is 193 63mg/kg 10-20cm,organic matter is 6.12g/kg,available nitrogen is 37.19mg/kg,available phosphorus is 51.41mg/kg available potassium is 171.24mg/kg,20-30cm,organic matter is 4.59g/kg,available nitrogen is 31.24mg/kg,Available phosphorus 3 8.26 mg/kg,available potassium 153.48 mg/kg.The water content of stable sedimentation area is 15.03%,unit weight is 0.93g/cm3,0-10cm,organic matter is 8.78g/kg,available nitrogen is 37.63mg/kg,available phosphorus is 58.85mg/kg,available potassium is 189.47mg/kg,10-20cm,organic matter is 10.52g/kg,available nitrogen is 41.08mg/kg,available phosphorus is 71.63mg/kg,available potassium is 205.31mg/kg,20-30cm,organic matter is 8.18g/kg,available nitrogen is 32.90mg/kg,available phosphorus is 46.01mg/kg,and available potassium is 155.74mg/kgIn the control area,water content was 15.03%,bulk density was 1.19g/cm3,0-10cm,organic matter was 6.98g/kg,available nitrogen was 32.99mg/kg,available phosphorus was 52-23mg/kg,available potassium was 160.06mg/kg,10-20cm,organic matter was 6.33g/kg,available nitrogen was 36.70mg/kg,available phosphorus was 50.03mg/kg,available potassium was 170.98mg/kg,20-30cm,organic matter was 3.82g/kg,available nitrogen was 36.39mg/kg,available phosphorus was 19.64mg/kg,and available potassium was 112.06mg/kg.2 The soil bulk density in the unstable settlement area is higher than that in the stable settlement area,which may be due to the geological fluctuation caused by subsidence,which makes the soil structure loose and reduces the bulk density.The effect of collapse on soil chemical properties is mainly reflected in the change of organic matter.The maximum range difference of organic matter change(the maximum nutrient minus the minimum nutrient,the same below)is 15.47g/kg in unstable subsidence area,11.59g/kg in stable subsidence area and 7.84g/kg in control area.The reason may be that the collapse changed the topography of the sample plot,made the organic matter move with the collapse slope,resulting in the difference of the distribution of organic matter in the sample plot.3 The analysis of variance shows that the physical properties of the three sample areas are basically different and the differences of bulk density and porosity are obvious.The chemical properties of organic matter and available nitrogen in the three plots were significantly different.4 The analysis of dispersion degree shows that the water content of the three sample areas is weak variation(less than 10%),and the other physical and chemical indexes of each area are basically medium variation.The coefficient of variation of bulk density of physical properties in unstable settlement area(14.17%)and stable settlement area(15.09%)was greater than that in control area(5.84%).The degree of variation of chemical properties in unstable settlement area and stable settlement area was different from that in control area.5 The correlation of different physicochemical properties at the same depth in each sampling area was mainly reflected in the soil chemical properties.The correlation coeficient of available nitrogen and available potassium was 0.873 at 20-30cm in the unstable settlement area,0.850 at 10-20cm in the stable settlement area,and 0.885 at 10-20cm.in the control area;Among the correlation results of soil physical and chemical properties at different depths in different areas,the correlation of available phosphorus at different depths in unstable settlement area was the most significant,the highest was 0.706,the correlation of organic matter at different depths in stable settlement area was the most significant,the highest was 0.559,and the correlation of organic matter at different depths in control area was the most significant,the highest was 0.550.6 The global distribution pattern of physical and chemical properties in unstable subsidence area,stable subsidence area and control area of Wangzhuang mining area in Changzhi is positive spatial correlation;The local distribution pattern of each region is that the soil with higher physicochemical properties is close to the soil with higher physicochemical properties(HH model),and the soil with lower physicochemical properties is close to the soil with lower physicochemical properties(11 model).The local distribution pattern of unstable and stable settlement areas is more complex than that of the control area,which means that the subsidence disturbs the original distribution of soil physical and chemical properties.7 The surface subsidence changed the elevation of the terrain,and then changed the surface slope,changed the spatial oorrelation between slope and soil bulk density,enhanced the spatial correlation between slope and soil bulk density in unstable settlement area,and turned the correlation between slope and soil bulk density in stable settlement area into spatial negative correlation;In addition,surface subsidence also changed the spatial correlation between slope and nutrients in unstable and stable subsidence areas.For the spatial correlation between slope and organic matter and available nitrogen,the spatial distribution pattern of unstable and stable subsidence areas was opposite to that of the control area,which was a positive spatial correlation.The spatial correlation of slope and available phosphorus available potassium,the spatial distribution pattern of the three regions is the same. |
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