Study On Spatial Distribution And Influential Of Soil Organic Carbon Density

Soil organic matter is the main source of soil fertility, which plays an important role in promoting plant growth and improving soil physical structure. Soil organic carbon as an important part of soil organic matter and soil carbon library as the biggest carbon pool in the global ecological system exert significant impact on the global climate change and ecological environment. Therefore, it’s necessary to investigate the spatial distribution features of soil organic carbon and its influencing factors for the further understanding of soil organic carbon content and varying pattern. Influenced by natural and social environment factors in the process of formation and development, spatial distribution characteristics of soil organic carbon have strong spatial heterogeneity and dependence.This article choose Yidu which is the transition zone between western Hubei mountainous and Jianghan plain, which has a complex terrain features of the city as the study area, to comprehensively analyze the relationship between the natural social environment variables and soil organic carbon. Terrain index and land use type and human activity is considered to be the important factors that affect soil organic carbon density distribution. In this arcticle, we use geostatistical analysis, variance analysis and buffer analysis respectively to discuss various influence factors on the mechanism of action of soil organic carbon density and size. Through corresponding mathematical methods to quantify qualitative factors, But because of the complexity of the environment variables and variability, if we simply make the environment variables as explanatory variables in the model, it can be easily to produce multiplicity, redundancy and collinearity problem, This paper will combine the extraction and concise path analysis and principal component method for information selection of representative variables, to serve for a more accurate soil organic carbon density model services. Use Ordinary Kriging and two types of Cokriging prediction models to predict the spatial of the soil organic carbon density, and compare the precision of the three methods. The results are as follows:(1)Soil organic carbon density ranged from 0.560 to 9.250 kg m-2, and the coefficient of variation was 37.9%, which suggests that the content of soil organic carbon density experienced a moderate degree of variation. In other word, obvious spatial variability was detected at different geographical position.(2)For this research, different kinds of landform soil organic carbon density is: high mountain(4.06±1.59 kg m-2)> middle mountain(3.75±1.54 kg m-2)> low mountain(3.52±1.12 kg m-2);at the beginning, the soil organic carbon density is droping in a small range, and then it raise up with the increase of the slope; the high value of SOCD are mostly in the back of the mountain; the soil organic carbon density of different land use type is: Urban settlements(3.848±1.16 kg m-2) > the land covered by forest, grass and water(3.82±1.59 kg m-2) > agricultural land(3.70±1.28 kg m-2) > unutilized land(2.30±1.23 kg m-2); With the increase of road network density, soil organic carbon density increased after the first.(3)The slope had a very remarkable negative relationship with SOCD(-0.239**),and had an influence on SOCD directly, there were a little factors on it; The slope had a very remarkable positive relationship with SOCD(-0.236**), and had an influence on SOCD indirectly.(4)The precision of the cokriging model based on principal component analysis the cokriging model based on slope and the ordinary kriging model is: COKPCA>COKβ>OK, the COKPCA model improved the precision of the soil organic carbon density, it has a good adaption in the prediction of the soil organic carbon density in the transition zone of Western Hubei mountainous and Jianghan plain.