Molecular characterization of soil organic matter from native vegetation-pasture-sugarcane transitions in Brazil

Autor(es)

da Silva Oliveira, Dener Marcio ^{[1, 2]} ; Schellekens, Judith ^[1] ; Pellegrino Cerri, Carlos Eduardo ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Dept Soil Sci, 11 Paduas Dias Ave, BR-13418900 Piracicaba, SP - Brazil

^[2] Colorado State Univ, Nat Resource Ecol Lab, 1231 East Dr, Ft Collins, CO 80523 - USA

• Tipo de documento: Artigo Científico
• Fonte: Science of The Total Environment; v. 548, p. 450-462, APR 1 2016.
• Citações Web of Science: 10

Resumo

Replacing pastures (PA) with sugarcane (SG) has been deemed an agronomically feasible strategy for sugarcane expansion in Brazil. However, there are some uncertainties about the environmental impacts regarding this land use change (LUC), mainly related to soil organic matter (SOM), a key factor of environmental sustainability of Brazilian ethanol. LUC-related losses of SOM can overcome the C savings from biofuels. The molecular composition of SOM was evaluated to understand the C dynamics regarding LUC from PA to SG, using native vegetation (NV) as reference. Our study area was located in the south-central region of Brazil. Soil sampling was performed at three depths (0-0.1 m, 0.2-0.3 m and 0.9-1 m) in three representative sites with known LUC history and management practice since 1970. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was chosen to study SOM chemistry. Content and isotopic composition of soil organic C and N were also determined. The LUC caused decreases on C and N contents and on delta C-13 isotopic values. Depth was the major factor that influenced SOM composition, while the influence of LUC was mainly evident in surface soils and diminished rapidly with depth. The main difference in SOM composition undergoing the conversion PA-SG was a higher contribution from compounds associated to fresh litter inputs. The high contribution from fresh litter, having a relatively low mean residence time and increasing decomposition rates, is probably a major factor that drives C losses in areas undergoing sugarcane expansion. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/03953-9 - Dinâmica da matéria orgânica em organossolos de turfeiras tropicais (Diamantina-MG, Brasil) - desenvolvimento de proxies moleculares para a reconstrução de mudanças paleoambientais
• Beneficiário: Judith Schellekens
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 15/14122-6 - Estimativa das alterações nos estoques de C no solo associadas à expansão da cana-de-açúcar em áreas de pastagens no Brasil
• Beneficiário: Dener Márcio da Silva Oliveira
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 14/08632-9 - Matéria orgânica do solo em áreas de mudança de uso da terra para cultivo da cana-de-açúcar no Centro-Sul do Brasil
• Beneficiário: Dener Márcio da Silva Oliveira
• Modalidade de apoio: Bolsas no Brasil - Doutorado