Controls of soil respiration in the global croplands

Authors: Pokhrel, Pramod; Bandaru, Varaprasad

Submitted to: Journal of Geophysical Research-Biogeosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2026
Publication Date: 7/24/2026
Citation: Pokhrel, P., Bandaru, V. 2026. Controls of soil respiration in the global croplands. Journal of Geophysical Research-Biogeosciences. 131(7). Article e2025JG009371. https://doi.org/10.1029/2025JG009371.
DOI: https://doi.org/10.1029/2025JG009371

Interpretive Summary: Soil respiration (Rs) is a key factor driving soil carbon balance under croplands. Understanding factors influencing Rs helps in improving soil carbon models and helps informing land management strategies. Given that there is limited information on how different factors influence Rs under global croplands, we conducted a meta-analysis using 102 published studies. We found that surface soil temperature primarily regulated Rs, with a significant portion of fluxes well under 15 Mg C ha-1 yr -1 in all climatic regions. Soils of snow regions had 22-35% higher Rs fluxes than the global average. Soil moisture primarily limited fluxes in arid and semi-arid environments, but the effect was minimal in warm-temperate and snow regions, where temperature limited Rs. No-tillage (NT) management reduced overall Rs by 21%; an additional 10% increase in NT cropland potently offset 0.28 Pg C y-1 Rs from global croplands. Our study findings highlight the effect of environmental and soil variables in cropland Rs on a regional scale, providing valuable information to the carbon modeling community.

Technical Abstract: Unlike natural ecosystems, agricultural practices influence microclimatic conditions in croplands. This drives fluctuations in soil respiration (Rs), yet there is limited understanding of how soil environmental variables and management regulate Rs across climatic regions. We analyzed 362 records from 102 published studies that measured Rs in croplands across global climate regions and assessed the effects of soil temperature, moisture, and tillage practices on cropland Rs. Surface soil temperature primarily affected Rs, with most annual Rs well under 15 Mg C ha-1 across all climatic regions. Soils of snow regions had 22%–35% higher Rs than the global average. The current global cropland annual Rs of 13.9 ± 6.4 Pg C could increase by 15%–30% by the end of 21st century, if soil temperatures rise by 2.3–4.5°C and current cropping practices continue. Soil moisture primarily limited Rs in arid and semi-arid environments but had minimal effect in warm-temperate and snow regions, where temperature limited Rs. No-tillage (NT) management reduced Rs by 21%; a 10% increase in NT adoption could offset 0.28 Pg C annual Rs from global croplands. However, high crop residue coupled with elevated soil temperatures (>25°C) can offset this benefit by enhancing microbial decomposition in cooler regions. Our findings suggest that soil temperature explained more variance in cropland Rs than differences among tillage types or crop species. Snow regions exhibit higher temperature sensitivity, with Rs potentially increasing by 22%–35% under warming scenarios. The region-specific temperature-Rs relationships of cropland carbon loss provide a quantitative basis for land management policies targeting soil carbon conservation.