Autoria: SANTA-ANNA, S. A. C. de; JANTALIA, C. P.; SA, J. M.; VILELA, L.; MARCHAO, R. L.; ALVES, B. J. R.; URQUIAGA, S.; BODDEY, R. M.

Resumo: Abstract: In Brazil?s central savanna region, government policy is to encourage the conversion of conventional plough tillage (PT) agriculture to no-till (NT) and raise the productivity of under-utilized pastures, including their conversion to integrated crop-livestock (ICL) systems, with the objective of increasing soil organic carbon (SOC) at the expense of atmospheric carbon dioxide. An experiment was established in 1991 by liming and fertilizing at two levels an area of native vegetation (NV). The treatments, replicated in randomized plots, included pastures, continuous cropping and ICL systems under PT or NT. The aim of this study was to quantify the SOC accumulation to 100 cm depth under these treatments over time. The high C:N ratios suggested that there was a high proportion of charcoal present in the soil. Increasing fertilizer inputs had no overall significant effect on SOC stocks. Stocks of SOC changed little under pastures. Analyses of ¹³C abundance showed that higher fertilizer inputs increased the decomposition rate of C derived from NV under pure grass pastures. Continuous cropping under NT preserved SOC and under PT there were significant losses. The highest SOC stocks were found under ILP treatments, but not all ILP treatments accumulated SOC even under NT. These results indicate that government initiatives to substitute PT with NT and to intensify beef cattle production will have only modest short-term gains in SOC accumulation.

Ano de publicação: 2016

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Cerrados

Palavras-chave: Abundância de Carbono, Carvão, Cerrado, Leguminosa Forrageira, Pastagens tropicais, Sequestro de carbono, Sistema de criação de gado integrado, Solo