Analysis Of Spatial And Temporal Changes And Influencing Factors Of Key Attributes Of Soil Organic Carbon Pool In Anhui Province

With global climate change becoming a global concern,the study of soil organic carbon（SOC）is of great significance to achieve the goal of carbon peak and carbon neutrality.Based on the data of the second soil census in 1985 and the soil profile data obtained by the 2018’China Soil Series’compilation project,this paper combines remote sensing data,digital elevation model（DEM）and meteorological data.The spatial differentiation characteristics of soil organic carbon density（SOCD）and soil organic carbon reserve（SOCR）in the surface soil（0～30 cm）of Anhui Province were analyzed.The correlation between SOC and its influencing factors was analyzed by SPSS statistical software,and the main influencing factors were extracted by principal component analysis.Based on the main influencing factors,a Geographically Weighted Regression（GWR）model was constructed.The influence degree and importance of the main factors on SOC were analyzed by local regression coefficients,and the main controlling factors affecting SOC changes in Anhui Province were clarified.The main achievements are as follows:（1）The spatial difference of SOCD in the surface soil（0～30 cm）of Anhui Province was obvious,and the spatial distribution showed the characteristics of high in the south and low in the north.The SOCD in the hilly area was higher than that in the plain area.In 1985 and 2018,the average SOCD was 4.77 kgm^-2 and 3.96 kgm^-2,and the SOCR was 6.71×10⁸ t and 5.63×10⁸ t,respectively.Compared with 1985,the storage of soil organic carbon pool in 2018 decreased by 1.08×10⁸ t,and the proportion of SOCD high value and low value area decreased by 8.56%and 25.43%respectively.（2）Eight influencing factors including terrain factors（elevation and slope）,meteorological factors（temperature and precipitation）,soil physical and chemical properties（bulk density and p H）,vegetation factors（NDVI）and land use were selected for research.The linear fitting results showed that SOC was significantly negatively correlated with bulk density,soil p H and land use index（P<0.01）,and positively correlated with elevation,precipitation and NDVI（P<0.01）.The slope in1985 was significantly negatively correlated with SOC,while the slope in 2018 was positively correlated with SOC（P<0.01）.The temperature in 1985 was positively correlated with SOC,while the temperature in 2018 was negatively correlated with SOC（P<0.01）.Different influencing factors have obvious spatial differentiation characteristics,and SOC has different responses to each influencing factor.（3）Principal component analysis was used to extract the main influencing factors of SOC in soil surface layer（0～30 cm）in Anhui Province.The results showed that the main influencing factors in 1985 included elevation,slope,temperature and precipitation,which were mainly manifested as the influence of rainfall runoff on SOC.The main influencing factors in 2018 were bulk density,p H,elevation,slope,temperature and precipitation,which were mainly reflected in the influence of rainfall runoff and soil physical and chemical properties on SOC spatial differentiation.（4）Based on the local regression coefficient of the GWR model,the correlation characteristics between the regression coefficients of the main influencing factors and SOC are analyzed.The results show that the GWR model predicts that the SOC in Anhui Province can properly reflect the influence of the main influencing factors in the local area,and its prediction results are better in the natural state or areas with weak human interference.According to the difference in the response of SOC to the main influencing factors at different spatial locations,it shows that temperature and slope are the main controlling factors that determine the spatial distribution pattern of SOC in Anhui Province.In summary,this study analyzed the spatial distribution and temporal and spatial variation characteristics of soil organic carbon pool density and storage in Anhui Province,and clarified the effects of environmental factors and human factors on SOC,indicating that temperature and vegetation are the key factors causing SOC changes.Figure[40]Table[13]Reference[162]...