Study On Estimation Of Soil Organic Carbon Storage In Houzhaihe Small Watershed In Guizhou, China

According to the principle of belt transect method, the typical bands of soil samples were set in Houzhai River Basin upstream, midstream and downstream in Puding County in Guizhou Province, which sampling band is provided with 6 parallel transects from north to south through the basin boundary and sampling bands within the sampling unit is 150 * 150m~2 square grid whose center was set sampling points.soil profiles were excavated and soil samples were collected with stratified banded in the sampling points. some indexes were determined such as soil organic carbon content, soil bulk density, soil thickness, soil distribution area and rocky exposed rate and estimation of soil organic carbon storage was discussed, which based on "method of soil types" in Houzhaihe small watershed. The results showed that:1、Spatial heterogeneity(1) There is bigger difference of the spatial distribution pattern of topography in the upstream, midstream and downstream in Houzhaihe small watershed, and spatial variability of lithology, soil, vegetation, land use and rocky exposed rate is larger in upstream, midstream and downstream in Houzhaihe small watershed.(2) Each sampling unit in the spatial distribution pattern of extremely is complex in Houzhaihe small watershed, and spatial variability of soil organic carbon content in different slope position, slope aspect, slope grade, and land use niche is higher.(3) The spatial variability of soil profile in each sample point is higher, and the difference is bigger in different soil layers, thickness of gravel content, classification,structure, texture and different root etc in the soil profile.2、Estimation of soil organic carbon storage(1) Since bigger spatial variability, the influence degree of different indexes estimating soil organic carbon storage is soil organic carbon content > rocky exposedrate > soil thickness> soil bulk density in karst area.(2) The computational formula and model estimating soil organic carbon storage in karst region with "method of soil types" should be revised by different indexes.(3) The soil organic carbon storage is 7.24* 105 t and the interval of surface soil organic carbon density is from 3.53 to 9.11 kg/m~2 and total soil organic carbon density is from 9.11 to 14.68 kg/m~2 with revised computational formula and model in Houzhaihe small watershed in Puding.