Gustavo de Angelo Lucaa, Izael Martins Fattori Juniora, Emerson Medeiros Del Ponteb, Fábio Ricardo Marina, c
- a“Luiz de Queiroz” College of Agriculture, University of São Paulo (ESALQ/USP), Av. Pádua Dias 11, Piracicaba, SP, 13418-900, Brazil
- bBrazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials (LNBR/CNPEM), Rua Giuseppe Máximo Scolfaro 10000, Polo II de Alta Tecnologia, Campinas, SP, 13083-100, Brazil
- cDepartment of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, 80521, USA
- dNatural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, 80521, USA
- eCenter for Nuclear Energy in Agriculture, University of São Paulo, SP, Brazil
- fCenter for Carbon Research in Tropical Agriculture (CCARBON), University of São Paulo, Piracicaba, SP, 13418-900, Brazil
Highlights
- Native vegetation showed greater POC and MAOC storage than croplands under CT and NT.
- POC storage was negatively driven by MAT and soil pH.
- MAOC storage was governed by mineral stabilization (silt + clay content).
- ΔPOC was positively related to NPP and soil pH, while ΔMAOC was negatively affected by MAP-PET.
- Soil MAOC accrual was not constrained by MAOC deficit, remaining below its maximum observed saturation capacity.
Abstract
The Brazilian Cerrado is a major global agricultural frontier, encompassing extensive croplands, pastures, and integrated production systems. While historical land use conversion has depleted soil organic carbon (SOC) stocks, developing strategic management practices is critical for soil recovery and climate change mitigation. Optimizing these strategies requires a precise understanding of the environmental drivers that govern the stabilization of particulate (POC) and mineral-associated organic carbon (MAOC) across the region’s diverse landscapes. We conducted a systematic meta-analysis combined with structural equation modeling to identify controls on POC and MAOC across land uses (croplands, pastures, integrated systems, and native vegetation), climate (mean annual temperature, MAT; mean annual precipitation minus potential evapotranspiration, MAP-PET), carbon input (net primary production, NPP), and soil properties (texture and pH). We further quantified ΔPOC and ΔMAOC following the conversion of native vegetation to agricultural systems. Native vegetation contained, on average, 7.3 g C kg−1 soil more MAOC than both croplands under conventional and no-tillage, and 3.4 g C kg−1 soil more POC than cropland under no-tillage. POC storage was negatively controlled by MAT and soil pH (r2 = 0.18), while MAOC depended primarily on silt and clay content (r2 = 0.55). Conversion of native vegetation to agricultural systems produced a broad range of ΔPOC and ΔMAOC responses. ΔPOC was positively associated with NPP and soil pH (r2 = 0.21), suggesting that increasing plant productivity through improved soil fertility is key for sustaining POC after land use change. Across systems, MAOC remained below its maximum mineralogical capacity, indicating no evidence of MAOC saturation limitation. These findings highlight the role of mineral protection in regulating stable SOC pools and the need for site-specific strategies to maximize plant inputs and minimize losses, thereby alleviating negative agricultural effects on SOC.
Keywords
Tropical climate; Soil organic matter fractionation; Structural equation models; Oxisols; Carbon saturation deficit; Integrated crop-livestock
