Influence of Crop Residue Management and Soil Tillage Method on Reducing the Carbon Footprint of Winter Wheat Production in the Salt-Affected Arable Land in the North China Plain

Abstract

Salt-affected arable land is distributed widely in China, especially in the North China Plain. Crop residue management under appropriate tillage is critical to improving salt-affected soil organic carbon and reducing the carbon footprint. This study conducted four-year field experiments including two treatments (residue incorporated into soil with plough tillage (CT+); residue mulching with no-till (NT+)) in two sites (non-saline soil and salt-affected soil); the carbon footprint of wheat production was analyzed by life cycle assessment. The results showed that the carbon footprint of wheat production in the salt-affected soil was significantly larger than that in the non-saline soil, because the salt-affected soil exhibited higher N2O emission than the non-saline soil. CT+ has lower carbon footprint than the NT+, mainly due to the lower N2O emission and higher carbon sequestration in the CT+ compared to NT+. As for the salt-affected soil, the largest contributor of the carbon footprint per unit area was soil N2O emission, with a relative contribution of 40%; the largest contributor of the carbon footprint per unit yield was carbon sequestration, with a relative importance of 47–50%. Our results indicated that wheat production in salt-affected land has a high carbon footprint, while it can be decreased by incorporating crop residue into the soil under the plough tillage.