Effects of conservation tillage on net carbon flux from farmland ecosystems

Based on a 5-year field experiment in winter wheat-maize double cropping area and by using West function, this paper studied the net carbon (C) release from farmland ecosystems under different tillage practices. The results indicated that during the five years, the C release from agricultural inputs under conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) was 312.60, 295.41 and 280.52 kg · km^-2 · a^-1, while the C sequestration in 0-30 cm topsoil was 30.59, 32.76 and 31.61 Mg · km^-2, with a net C flux being 312.60, - 138.59 and -76.52kg · km^-2 · a^-1, respectively. Compared with CT, the relative net C flux under NT and RT was -236.08 and - 451.19 kg · km^-2 · a^-1. The decrement of the C release from agricultural inputs under NT (32.08 kg · km^-2 · a^-1) was 15.73% of the increment of C sequestration (204.00 kg · km^-2 · a^-1) while that under RT (17.19 kg · km^-2 · a^-1) was 3.96% of the increment of C sequestration (434.00 kg · km^-2 · a^-1). RT had a greater contribution than NT in the atmospheric CO₂ reduction.