Effect of straw retention on carbon footprint under different cropping sequences in Northeast China

Inappropriate farm management practices can lead to increased agricultural inputs and changes in atmospheric greenhouse gas (GHG) emissions, impacting climate change. This study was initiated in 2012 to assess the potential for straw retention to mitigate the negative environmental impact of various cropping systems on the Songnen Plain using the life cycle assessment (LCA) method combined with field survey data. Straw retention (STR) and straw removal (STM) treatments were established in continuous corn (CC) and corn-soybean rotation (CS) systems in a split-plot experiment. The effects of straw retention on the carbon footprint (CF) of cropland under different cropping systems were compared. The CF under CC was 2434-2707 kg CO₂ ha^-1 year^-1, 49-57% higher than that under CS. Nitrogen fertilizer produced the most CO₂, accounting for 66-80% of the CF. The carbon balances of the CC and CS systems with STR were positive, with annual carbon sequestrations of 9633 and 2716 kg CO₂ ha^-1 year^-1, respectively. The carbon balance (CB) of CC-STR was 255% higher than that of CS-STR. This study demonstrates that STR under CC cultivation is an environmentally friendly practice for agricultural production, can help achieve high-yield and low-carbon production in rainfed cropland, and can support the sustainable development of grain production in Northeast China.