Closing Greenhouse Gas Emission Gaps of Staple Crops in China

Abstract

China is facing the dual challenge of achieving food security and agricultural carbon neutrality. Developing spatially explicit crop emission profiles can help inform policy to mitigate agricultural greenhouse gases (GHGs), but previous life-cycle studies were conducted mostly at national and provincial levels. Here, we estimate county-level carbon footprint of China’s wheat and maize production based on a nationwide survey and determine the contribution of different strategies to closing regional emission gaps. Results show that crop carbon footprint varies widely between regions, from 0.07 to 3.00 kg CO2e kg–1 for wheat and from 0.09 to 2.30 kg CO2e kg–1 for maize, with inter-county variation generally much higher than interprovince variation. Hotspots are mainly concentrated in Xinjiang and Gansu provinces, owing to intensive irrigation and high plastic mulch and fertilizer inputs. Closing the regional emission gaps would benefit mostly from increasing crop yields and nitrogen use efficiency, but increasing manure use (e.g., in Northeast, East, and Central China) and energy use efficiency (e.g., in North and Northwest China) can also make important contributions. Our county-level carbon footprint estimates improve upon previous broad-scale results and will be valuable for detailed spatial analysis and the design of localized GHG mitigation strategies in China.

Toward Low-Carbon Rice Production in China: Historical Changes, Driving Factors, and Mitigation Potential

“…All data sources and processing methods are elaborated in Text S1. The GHG emissions from manure processing were excluded from the system boundary as we attributed them to animal husbandry systems . To ensure the representativeness of EF, this study applied average EF values for each agricultural input, which were sourced from multiple literature sources and databases (Tables S1 and S2).…”

“…Life cycle assessment (LCA) is a systematic methodological framework for evaluating the consumption of resources and environmental impacts associated with various stages of a product . Over the past few decades, the LCA has been widely employed to enhance the understanding of GHG emissions from the production of agricultural products. − Based on the LCA, carbon footprint (CF) was utilized as a comprehensive indicator to encompass all aspects of carbon emissions and carbon sequestration during agricultural production, such as indirect emissions from agricultural materials, direct emissions from field soil, and carbon sequestered into the soil. , Currently, numerous studies have quantified the CF for rice at the provincial or national level, − which provide valuable insights into the GHG emissions from rice production. However, environmental conditions and farming practices exhibit significant variations across diverse rice cropping regions.…”

Carbon Sequestration Strategies in Soil Using Biochar: Advances, Challenges, and Opportunities

“…It should be noted that even with such a standardized method as LCA, results can be vastly different and sometimes do not allow direct comparisons between these studies. 167,173 To a large extent, the differences between LCA studies are due to the inconsistency in the selection of system boundary, inventory models, and methodological decisions. 26,170 For instance, the contribution of biogenic C, including vegetation C sequestration, is usually excluded from C balance calculations according to IPCC guidelines.…”

“…It should be noted that even with such a standardized method as LCA, results can be vastly different and sometimes do not allow direct comparisons between these studies. , To a large extent, the differences between LCA studies are due to the inconsistency in the selection of system boundary, inventory models, and methodological decisions. , For instance, the contribution of biogenic C, including vegetation C sequestration, is usually excluded from C balance calculations according to IPCC guidelines . Recent evidence indicates that biogenic C matters in the C balance because there is a large time difference between the uptake (sequestration in plant) and emission (decomposition of plant residue) of biogenic C. , Whether biogenic C is included in the LCA will significantly affect the C sequestration potential of biochar .…”

Effects of elevated CO2 concentration gradients on rice grain quality under two cultivation practices in cold region

“…Rice cultivation in China requires 65% of the freshwater resources for diffuse irrigation (Alhaj Hamoud et al, 2018), so there is an urgent need to solve the problem of insufficient freshwater resources in rice production. The non‐flooded plastic film mulching rice cultivation technology has been created to solve the contradictory problem of water supply and demand (Liu et al, 2022; Xia et al, 2022).…”