Soil carbon, nitrogen and phosphorus changes under sugarcane expansion in Brazil

Autor(es)

Franco, Andre L. C. ^[1] ; Cherubin, Mauricio R. ^[1] ; Pavinato, Paulo S. ^[2] ; Cerri, Carlos E. P. ^[2] ; Six, Johan ^[3] ; Davies, Christian A. ^[4] ; Cerri, Carlos C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13416000 Piracicaba, SP - Brazil

^[2] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Dept Soil Sci, BR-13418900 Piracicaba, SP - Brazil

^[3] ETH, Dept Environm Syst Sci, CH-8092 Zurich - Switzerland

^[4] Shell Technol Ctr Houston, Houston, TX 77082 - USA

• Tipo de documento: Artigo Científico
• Fonte: Science of The Total Environment; v. 515, p. 30-38, MAY 15 2015.
• Citações Web of Science: 29

Resumo

Historical data of land use change (LUC) indicated that the sugarcane expansion has mainly displaced pasture areas in Central-Southern Brazil, globally the largest producer, and that those pastures were prior established over native forests in the Cerrado biome. We sampled 3 chronosequences of land use comprising native vegetation (NV), pasture (PA), and sugarcane crop (SC) in the sugarcane expansion region to assess the effects of LUC on soil carbon, nitrogen, and labile phosphorus pools. Thirty years after conversion of NV to PA, we found significant losses of original soil organic matter (SUM) from NV, while insufficient new organic matter was introduced from tropical grasses into soil to offset the losses, reflecting in a net C emission of 0.4 Mg ha(-1) yr(-1). These findings added to decreases in N-15 signal indicated that labile portions of SUM are preserved under PA. Afterwards, in the firsts five years after LUC from PA to SC, sparse variations were found in SUM levels. After more than 20 years of sugarcane crop, however, there were losses of 40 and 35% of C and N stocks, respectively, resulting in a rate of C emission of 1.3 Mg ha(-1) yr(-1) totally caused by the respiration of SUM from C4-cycle plants. In addition, conversion of pastures to sugarcane mostly increased N-15 signal, indicating an accumulation of more recalcitrant SUM under sugarcane. The microbe- and plant-available P showed site-specific responses to LUC as a function of different P-input managements, with the biological pool mostly accounting for more than 50% of the labile Pin both anthropic land uses. With the projections of 6.4 Mha of land required by 2021 for sugarcane expansion in Brazil to achieve ethanol's demand, this explanatory approach to the responses of SUM to LUC will contribute for an accurate assessment of the CO2 balance of sugarcane ethanol. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 12/22510-8 - Macroinvertebrados e os processos de engenharia do solo: controles sobre a estocagem de matéria orgânica do solo em áreas com mudanças no uso da terra
• Beneficiário: Andre Luiz Custodio Franco
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 13/17581-6 - QUALIDADE DO SOLO EM ÁREAS DE MUDANÇA DE USO DA TERRA PARA CULTIVO DA CANA-DE-AÇÚCAR NO CENTRO-SUL DO BRASIL - bases para avaliação da sustentabilidade ambiental do etanol
• Beneficiário: Maurício Roberto Cherubin
• Modalidade de apoio: Bolsas no Brasil - Doutorado