Temporal and spatial dynamics of carbon footprint in emerging rice production regions of China

Updating and quantifying the carbon footprint (CF) of rice production systems can provide valuable insights for developing effective agricultural emission strategies and policies. This study broadens the scope of CF research and calculated the temporal and spatial variations in the CF of a typical emerging rice production system in China from 1992 to 2022. The results show that from 1992 to 2022, the net CF per hectare (CFArea) increased from 5.2 to 6.3 t CO2 equivalents (CO2 eq) hm−2, while the net CF per ton (CFYield) decreased from 1.11 to 0.84 t CO2 eq t−1. The carbon emission (CE) related to methane emission (CECH4) became the largest contributor to CE, rising from 16.8 % to 49.5 %. The CE related to straw utilization (CEStraw) decreased from 59.6 % to 29.5 %. The CE related to agricultural materials input (CEMaterials) and N2O and NH3 emissions (CENitro) ranging from 8.8 % to 10.5 % and 11.1 % to15.4 %, respectively. The carbon sequestration related to soil (CSSoil) could offset 14.3 % to20.9 % CE. Spatial analysis shows that regions like Jiamusi and Harbin are facing high CFs and significant environmental pressures. Increasing straw return to fields helped reduce both CEStraw and CEMaterials, while enhancing CSSoil, although it had minimal effect on reducing CECH4. Scenario analysis suggests that straw management is more effective in reducing emissions compared to managing agricultural materials. In conclusion, implementing sustainable straw return practices and enhancing soil carbon storage will be key strategies in reducing emissions from rice production systems.