采用大田试验、室内分析与生产调研相结合的方法，研究了耕作方式对农田生态系统固碳能力的影响.结果表明：少、免耕以及秸秆还田等保护性耕作措施有利于土壤有机碳的累积；免耕秸秆还田（NTS）方式0～5 cm土层土壤有机碳累积量比传统耕作（CTA）方式高18.0%，旋耕秸秆还田（RTS）0～5和5～10 cm土层比CTA分别高17.6%和25.0%，而翻耕秸秆还田（CTS）方式10～30 cm土层土壤总有机碳累积量比CTA高31.8%；CTA转变为NTS后，源于农田投入的碳排放减少了54.3 kg·hm-2·a-1，而转变为CTS、RTS后，分别增加了46.9 kg·hm-2·a-1和34.4 kg·hm-2·a-1；综合土壤碳累积与农田投入碳排放可知，传统耕作转变为保护性耕作方式后可实现由“碳源”向“碳汇”的转变，而CTS、RTS、NTS 3种耕作方式中以RTS的固碳能力最强,达1011.1 kg·hm-2·a-1.
By the methods of field experiment, laboratory analysis, and in situ investigation, this paper studied the effects of different tillage conversion on the carbon sequestration capability of farmland soil doubled cropped with wheat and corn. Compared with conventional tillage (CTA), conservation tillage practices benefited the accumulation of soil organic carbon, among which, notillage plus straw returning (NTS) increased the organic carbon accumulation in 0-5 cm soil layer by 18.0%, rotary tillage plus straw returning (RTS) increased this accumulation in 0-5 and 5-10 cm soil layers by 17.6% and 25;0%, respectively, and conventional tillage plus straw returning (CTS) increased the organic carbon in 10-30 cm soil layer by 31.8%. After the conversion from CTA to NTS, the carbon emission from farm operations decreased by 54.3 kg·hm-2·a-1; while the conversion from CTA to CTS and RTS resulted in an increase of this emission by 46.9 kg·hm-2·a-1 and 34.4 kg·hm-2·a-1, respectively. Considering of the accumulation of soil organic carbon and the carbon emission from farm operations, it could be concluded that the conversion from CTA to conservation tillage changed this farmland soil from carbon source to carbon sink, and the RTS among the three conservation tillage modes resulted in the highest soil carbon sequestration (1011.1 kg·hm-2·a-1).