Effects of Coal Mining Subsidence on Soil Organic Carbon in Jining Coal Mining Area

Cheng Yanan; Li Xinju

doi:10.14083/j.issn.1001-4942.2018.03.017

Abstract：The coal mining causes surface subsidence.The original landform changes a lot,and the soil is seriously disturbed,which resulting in soil nutrient transformation and migration at large spatial variation. The variation of soil organic carbon is the key representation factor of soil nutrient.The study on the impacts of land subsidence on soil organic carbon has gradually become a hot issue of reclamation soil quality.In this study,a typical subsidence area in Yanzhou coal mining area of Jining was selected to collect soil samples at different slope positions and depths,and the distribution characteristics and influencing factors of soil organic carbon on the slope and vertical profiles were analyzed.The results were as follows.(1)In the slope direc-tion,soil organic carbon showed decreasing at first and then increasing from the top to the edge of water trans-fer,and enriched at the collapse center.The effects of mining subsidence on soil organic carbon content on the middle and base of slope had significant differences(P<0.05).(2)In the vertical section, the content of soil organic carbon decreased with the increase of depth in soil profile.The content of organic carbon was mainly concentrated in the 0~20-cm soil layer,accounting for 65.9%of the whole soil(0~60 cm),and it was significantly higher than those in the soil layer below 20 cm(P<0.05).(3)The spatial variability de-gree of different soil properties are ranked as follows:organic carbon>thermal conductivity>water content>bulk density>pH value.(4)Soil organic carbon were negatively related with soil bulk density, water con-tent,pH value and thermal conductivity,and the correlation with water content reached a significant level with the correlation coefficient as -0.493*(P <0.05); the correlations with the bulk density and pH value reached very significant levels with the correlation coefficients as -0.699**and -0.684**(P<0.01);and the correlation with thermal conductivity did not reach the significant level.The land slope caused by land subsidence had already caused the loss of soil organic carbon,which further resulting in decline of soil fertility and land productivity.