Effect Of Soil Erosion On Soil Organic Carbon In Chinese Loess Plateau

The Chinese Loess Plateau suffers severe soil erosion. Soil erosion results in the decrease of soil quality and the loss of soil organic carbon storage .Soil organic carbon storage is the largest carbon storage in terrestrial ecosystem,and plays an important role in global carbon dynamic . This research could help us understanding the mechanisms of soil organic carbon lost and remove in erosive conditions . Further more,it has an important sense on improving the soil erosion status .Based on the typical slope in Loess Plateau in China,we measured the content and storage of soil total organic carbon(TOC),total nitrogen(TON)and soil labile organic carbon in different slope positions . Soil labile organic carbon contains Microbial Biomass Carbon(MBC),Dissolved Organic Carbon(DOC)and Readily Oxidation Carbon(ROC)in this research. Soil erosion/deposition on the slope was determined from measurement of 137Cs inventory. The main results are summaried as follows:1 The upper slope is the severe eroded site,the middle slope is the light eroded site and the bottom slpoe is the deposition site.2 There were significant differences between TOC and TON among different eroded sites and deposition site. The TOC and TON at those three slpoe sites were smaller than reference site.The vertical distribution of soil organic carbon and total organic nitrogen declined gradually in the soil profile from top to 45cm depth. Furthermore,the TOC and TON storage had significant differences too.3 Soil labile organic carbon were significantly lower at the three slope sites than at reference site. The change trends of MBC and ROC were similar with TOC except DOC,whose content and storage had no significant differences between eroded sites and deposition site. The vertical distribution of MBC and ROC declined gradually in the soil profile from top to 45cm depth,but the DOC in deep profiles were larger than top profiles'.4 There were significant correlationship among TOC and MBC,ROC,but no significant correlationship with DOC. Additionally,there was positive significant correlationship between MBC and ROC,but there weren't significant correlationship among DOC and MBC,ROC.