Effect on soil active carbon and soil C pool management index of different tillages

Based on the experiment of 6-year conservation tillage in Dingxi specific semiarid areas in the Loess Plateau.The total organic carbon(TOC) and active soil organic carbon(ASOC) of different tillage methods were studied,and the activity of carbon pool(A),activity index(AI),carbon pool index(CPI),carbon pool management index(CPMI) of different treatments were calculated.The results showed that the contents of TOC and ASOC in no-till with straw mulching(NTS),conventional tillage with straw incorporated(TS),non-till without straw mulching(NT) were more than conventional tillage with no straw(T),and the contents of TOC and ASOC decreased with the soil depth.The percentage of ASOC in TOC was higher in NT,NTS and TS than T in 0～5 cm soil layer,especially in NTS.The result demonstrated that the activity of the carbon in soil of NTS was higher and could convert easily.Stubble return effect was more than tillage form for different soil C pool management index,so stubble return was advantages to improving the soil C pool management index.