Abstract:

In order to understand the effects of different models of straw returning to field on soil fertility of double-harvest rice field, the TOC (total organic carbon), AC (active carbon) pool and M (mineralized carbon) were analyzed, and A (carbon pool active), AI (carbon pool active index), CPI (carbon pool index) and CPMI (carbon pool management index) were calculated. The results indicated that comparing with the not applied fertilizer treatment (CK), CTOC, CA, CM and the available ratio of soil carbon were increased under early and late season rice straw returning to field. Under the condition of the same nutrient application, CTOC, CA and the available ratio of soil carbon with straw returning to field were higher than that of straw incineration and straw no returning, while the soil CA content had more change. The carbon pool management index (CPMI) was significant difference or very significant difference among treatments, and the order was straw returning to field > straw incineration to field > straw no returning to field.