Chen Z.-D., Dikgwatlhe S.B., Xue J.-F., Zhang H.-L., Chen F., Xiao X.-P.
College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China; Limpopo Department of Agriculture, Research Services, Plant Production Systems Division, Polokwane, South Africa; Hunan Soil and Fertilizer Institute, Changsha, China
Chen, Z.-D., College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China; Dikgwatlhe, S.B., College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China, Limpopo Department of Agriculture, Research Services, Plant Production Systems Division, Polokwane, South Africa; Xue, J.-F., College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China; Zhang, H.-L., College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China; Chen, F., College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China; Xiao, X.-P., Hunan Soil and Fertilizer Institute, Changsha, China
Scientific regulation of carbon (C) flows under conservation tillage is of great significance for mitigating C emission to the atmosphere and increasing C sequestration potential in soils. The objective of this study was to assess tillage impacts on C cycle from a situ field experiment and identify potential tillage practices for C-smart technology in paddy soils of the Southern China. A field experiment was conducted during 2005-2011, including conventional tillage without residue retention (CT), conventional tillage with residue retention (CTS), rotary tillage with residue retention (RTS), and no-till with residue retention (NTS). We computed SOC concentrations, SOC stocks and C emissions from farm inputs with time, and results in values representing a change in net carbon flux under different tillage systems in a double rice (Oryza sativa L.) cropping system. The annual increase rates of SOC stocks were 452.6, 523.3, 1340.8, and 2385.4 kg ha-1 yr-1 from 2007 to 2011 under CT, CTS, RTS, and NTS, respectively. The annual C emissions under CT, CTS, RTS, and NTS were 1182.5, 1182.5, 1152.5, and 1139.2 kg C-eq ha-1 yr-1, respectively. Among the treatments, NTS treatment had the lowest net C flux with -1246.2 kg C-eq ha-1 yr-1. Taking CT as the baseline, the relative net C flux under RTS and NTS were -918.2 and -1976.1 kg C-eq ha-1 yr-1, respectively. This suggests that adoption of conservation tillage would be beneficial in the reduction of GHG emission and could be a good option for C-smart agriculture in double rice cropping regions. © 2014 Elsevier Ltd.