Spatial And Temporal Variation Of Soil Organic Carbon In Late 30 Years Of Western Sichuan And Its Response To Climate Change

Soil organic carbon(SOC)plays an important role in terrestrial ecosystems by affecting soil properties and quality.Accurate prediction of soil organic carbon’s spatial and temporal variation and its response to climate change is a hot topic in the study of carbon cycle in ecosystem.This research according to 1983 soil samples of the 1980s’ the second soil census and 2747 soil samples of 2010s’ field sampling in western Sichuan province,as well as 1980s and 2010s’ annual average temperature and annual average precipitation data of 97 county-level meteorological stations Inside and outside the study area.Geostatistics as the theory basis for using GS + and ArcGIS10.2 software platform to predict 1980s and 2010s’ spatial distribution of soil organic carbon,temperature and precipitation in the study area.Using statistical analysis and variance analysis to explore the main factors of soil organic carbon’s spatial variation in the study area and the correlation of soil organic carbon and climate change.Results indicated that:(1)the mean content of soil organic carbon in topsoil layer was 27.45 g/kg in 1980s and 21.16g/kg in 2010s,soil organic carbon decreased by 22.92% from 1980s to 2010s;the coefficient of variation decreased from 95.99% to 56.57% and the degree of spatial variation weakened.The spatial variation of soil organic carbon in the two periods was affected by both structural factors and random factors,and two periods’ spatial distribution of soil organic carbon were roughly the same,showing a decreasing trend from northwest to southeast in the study area.In the past 30 years,the change of soil organic carbon in the study area has a high spatial variability.(2)In recent 30 years,the annual average temperature in the study area increased slightly,and the annual average precipitation decreased slightly.The spatial variation of temperature and precipitation in the two periods was mainly affected by structural factors.In terms of spatial distribution,the annual average temperature and annual average precipitation in most areas of the study area all showed an increasing trend and the variation of the both showed a high degree of spatial variability.(3)Factors such as air temperature and precipitation influenced the spatial variation of soil organic carbon in 1980s and 2010s.Compared with the 1980s,the impact of various influencing factors to soil organic carbon’s variation decreased in different degrees.In the 1980s and 2010s,soil organic carbon was significantly different under different influencing factors classification.(4)In the past 30 years,the average content of soil organic carbon in cultivated land and forest-grassland in the research area showed a decreasing trend under the different increase of temperature and precipitation.the decrease of arable soil organic carbon content of the study area was positively correlated with the increase of temperature and precipitation.The correlation between changes of soil organic carbon content in forest,grassland and changes of temperature,precipitation were more complicated,including both positive and negative correlation.