Soil carbon allocation, composition, and sequestration changes induced by cropping diversification in tropical systems

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Locatelli, Jorge Luiz ; Santos, Rafael Silva ; Tenelli, Sarah ; Soares, Matheus Bortolanza ; Del Grosso, Stephen ; Stewart, Catherine E. ; Popin, Gustavo Vicentini ; Bertol, Felipe Dalla zen ; Carvalho, Joao Luis Nunes ; Cherubin, Mauricio Roberto ; Cerri, Carlos Eduardo Pellegrino

• Tipo de documento: Artigo Científico
• Fonte: SOIL & TILLAGE RESEARCH; v. 248, p. 15-pg., 2025-01-26.

Resumo

Physical protection by carbon (C) occlusion inside soil aggregates is assumed to be a key mechanism for C stabilization. Nevertheless, little is known about how cropping diversification strategies affect C allocation and protection in soil aggregates and their stability, especially in highly weathered tropical soils. This study evaluated how cover crops and no-tillage affect soil organic matter (SOM) storage and aggregation in a tropical clayey Oxisol in the Brazilian Cerrado region. Changes in soil C and nitrogen (N) stocks, soil aggregate stability, C allocation within aggregates, and C speciation within aggregate classes using spectroscopy analysis were quantified. Soil C and N stocks under the most complex crop systems with cover crops increased by similar to 20 % and 29 %, respectively, compared to soybean-maize double cropping. The systems including cover crops increased soil aggregate stability, doubling large macroaggregation in the 5-10 and 10-20 cm depths. Increased aggregation under cover crops enhanced C contents within aggregates, i.e., similar to 48 %, 32 %, and 34 % higher for large macroaggregates, macroaggregates, and microaggregates, respectively, compared to soybean-maize double cropping (average considering different layers and cover cropping systems). Spectroscopy analysis showed that the diverse cropping systems increased the aromatic C (i.e., C=C/C-C) in large macroaggregates at the 0-5 cm layer while reducing oxidized groups, i.e., C=O/O=CO and C-O. Overall, our results revealed that cropping diversification is an effective strategy for increasing soil aggregate stability and physical protection of C (especially aromatic), and therefore can promote soil C storage in tropical soils. (AU)

• Processo FAPESP: 20/15230-5 - Centro de Pesquisa e Inovação de Gases de Efeito Estufa - RCG2I
• Beneficiário: Julio Romano Meneghini
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia
• Processo FAPESP: 21/10573-4 - Centro de Pesquisa de Carbono em Agricultura Tropical (CCARBON)
• Beneficiário: Carlos Eduardo Pellegrino Cerri
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs