The Spatial Distribution Of Soil Carbon In Small Watershed Of The Karst Fault Basin

Karst faulted basin is a typical ecologically fragile area in karst regions in southwest of our country.It is one of the important ecological recovery and reconstruction karst area.Faulted basin area has terribly undulates land form,great difference of altitude and evidently climatic vertical zone and buried subterranean stream.The special differentiation geological structure which has coexistence mountain and basin restrict geomorphological evolution of the faulted basin and the spatial variation pattern of rock,soil water and plants.It has significantly different with karst depressions,plateaus and troughs.The research of soil carbon stocks in karst area is a important part of the research of terrestrial ecosystem carbon cycle,has been widespread concern in academia.However,there are lack of the study of soil carbon stocks in karst fault basin area.In this paper,author selected Jiubiao small watershed in Karst area in southeast Yunnan as an example to research soil carbon factors and spatial distribution.Base on GIS and use geostatistical method to analyze the spatial variability of soil carbon,spatial distribution pattern and terrain factors on the distribution of soil carbon in Jiubiao watershed.On the hand,it is benefit to regional carbon cycle research,on the other hand,it can also provide a reference for the restoration of the ecological environment in karst area.The main conclusions are as follows.(1)In the research area,in different types of vegetation,there are significant differences in soil organic carbon(SOC),soil dissolved organic carbon(DOC)and inorganic carbon(SIC)of the content and distribution.Soil organic carbon content expressed as Eucalyptus robusta Smith forest land > Cupressus lusitanica Miller land > Pinus massoniana Lamb forest land >Dodonaea viscosa forest land > farmland;Soil dissolved organic carbon content in the order of farmland > Pinus massoniana Lamb forest land > Dodonaea viscosa forest land > Cupressus lusitanica Miller land > robusta Smith forest forest land;Inorganic carbon content in the orderconsist of Pinus massoniana Lamb forest land > Cupressus lusitanica Miller land > Dodonaea viscosa forest land > Eucalyptus robusta Smith forest land> farmland.(2)The three elements of terrain factors(slope,sea level,aspect)and the relationship between soil carbon was studied,the results show that the different elevation gradient analysis in the studied area,soil organic carbon and soil inorganic carbon and altitude were extremely significant correlation(P < 0.05),soil organic carbon content increased with the increase of altitude,soil inorganic carbon content reduce with the increase of elevation;Slope and soil organic carbon and inorganic carbon content were significantly correlated(P < 0.05),where slope < 5°,soil organic carbon and inorganic carbon content is significantly higher than other slope gradient,no significant difference between the other gradient.The Relationship between Aspect and organic carbon may lead to differences in the light of differences bio-synthesis of organic carbon content,resulting in the amount of organic carbon in the soil of different input caused.(3)On spatial pattern,soil organic carbon content of surface layer in the shrub land on the southern slope of was significantly higher than the North Slope in the watershed.Under the similar conditions temperature,hydrology,soil,etc.,Due to the sunny slopes get more calories than shady slope,so the sunny slopes of organic carbon accumulation rate is higher than the shady slopes.From the point of view topographic position,Watershed maximum accumulation of organic carbon in the undulating terrain of flat terrain,ditch,followed by other parts of the accumulation of organic carbon were less than two parts..