Restoring particulate and mineral-associated organic carbon through regenerative agriculture

[Geoengineering News]

https://www.pnas.org/doi/10.1073/pnas.2217481120

Authors

Aaron M. Prairie https://orcid.org/0000-0001-8192-9329 a.pr...@colostate.edu, Alison E. King https://orcid.org/0000-0002-4155-577X, and M. Francesca Cotrufo https://orcid.org/0000-0002-6191-8953

May 15, 2023

120 (21) e2217481120

https://doi.org/10.1073/pnas.22174811

Significance

Regenerating soil organic carbon (SOC) in agricultural soils is one of the most realizable nature-based solutions to mitigate global warming and sustain food production. To better understand SOC formation and persistence we need to separate it into two distinct forms, particulate organic carbon (POC) and mineral associated (MAOC). This study presents results from a global meta-analysis on the response of SOC, POC, and MAOC, to regenerative agricultural practices including no-till, cropping system intensification, and integrated crop–livestock (ICL). We found that regenerative practices increased both POC and MAOC, thus improving soil health and promoting long-term carbon storage. Our most interesting finding was the tremendous potential to increase SOC pools through synergistic interactions between multiple practices especially in ICL systems.

Abstract

Sustainability of agricultural production and mitigation of global warming rely on the regeneration of soil organic carbon (SOC), in particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) forms. We conducted a global systematic meta-analysis of the effects of regenerative management practices on SOC, POC, and MAOC in cropland, finding: 1) no-till (NT) and cropping system intensification increase SOC (11.3% and 12.4%, respectively), MAOC (8.5% and 7.1%, respectively), and POC (19.7% and 33.3%, respectively) in topsoil (0 to 20 cm), but not in subsoil (>20 cm); 2) experimental duration, tillage frequency, the intensification type, and rotation diversity moderate the effects of regenerative management; and 3) NT synergized with integrated crop–livestock (ICL) systems to greatly increase POC (38.1%) and cropping intensification synergized with ICL systems to greatly increase MAOC (33.1 to 53.6%). This analysis shows that regenerative agriculture is a key strategy to reduce the soil C deficit inherent to agriculture to promote both soil health and long-term C stabilization.

Overall response of carbon concentrations (g C kg soil−1) in total SOC, MAOC, and POC to regenerative agricultural management in topsoil (A, 0 to 20 cm) and subsoil (B, 20 to 100 cm). NT systems are compared to CT systems. Cropping intensification includes i) eliminating summer fallow in monocrop systems, ii) increasing the number of annual crops grown per year, iii) planting cover crops, and iv) incorporating perennial crops in rotation. Effect sizes were considered significant if 95% CI did not overlap zero.

Source: PNAS