Impact of Eight-Year Topsoil Removal and Soil Amendments on Soil Carbon Dioxide Emission in an Eroded Chinese Mollisols

Soil erosion is a serious environmental issue. Information in the severity of soil erosion on CO2 emission is limited. A soil erosion simulation experiment was used to examine the influence of topsoil removal and cattle manure amendment on soil CO2 emission for a cultivated Mollisols in Northeast China. Soil CO2 flux was determined during corn (Zea mays L.) growing season. Our results showed that aft er 8-yr treatment, topsoil removal decreased CO2 emission in the order of 30 cm < 10 cm < 5 cm < 20 cm < 0 cm under chemical fertilizer treatment alone and 20 cm < 10 cm < 30 cm < 5 cm < 0 cm for cattle manure addition. At the same erosion depth, cattle manure addition increased soil CO2 emission compared to chemical fertilizer alone treatment. During growing season, the CO2 flux pattern changed from one peak in chemical fertilizer alone treatment to two peaks in cattle manure addition treatments. In the chemical fertilizer alone system, only microbial biomass carbon (MBC) and dissolved organic carbon (DOC) fractions were significantly correlated with total CO2 emission. However, cattle manure addition changed the relationship between soil C fraction and CO2 emission. The MBC, particulate organic carbon (POC), and light fraction organic carbon (LOC) were significantly positively correlated with total CO2 emission. Though on-site CO2 emission was significantly reduced aft er the soil was severely eroded, restoration of eroded soil productivity by cattle manure amendments might release more CO2 emission into the atmosphere. Adoption of cattle manure application to eroded Mollisols needs considering the potential negative impact of more CO2 emission