Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11024793 | Geoderma | 2019 | 8 Pages |
Abstract
Millions of hectares (ha) of the Atlantic forest of Brazil have been deforested and replaced by pastures, quite a large proportion of this in the last 60â¯years. There have been few studies on the impact of this land-use change on stocks of soil organic matter (SOM) only one study reported the state of vigour of the pastures. The aim of this study was to estimate the overall change in SOM stocks 16â¯years after the removal of forest vegetation in this biome in southern Bahia and the installation of pastures of Brachiaria brizantha fertilized with N and maintained under controlled grazing. Soil samples were taken for evaluation of density and texture and for analyses of C and N total and 13C abundance to a depth of 100â¯cm at 100â¯m intervals along four transects of 400â¯m from the pastures into the forest. Grazing was found not to have any significant effect on soil density (compaction). The live weight gain of the Nellore cattle on both cultivars of B. brizantha, fertilized with 120â¯kgâ¯Nâ¯haâ1â¯yrâ1 as urea during 12â¯years, was close to 500â¯kgâ¯haâ1â¯yrâ1. The gain in soil C was similar under the two grass cultivars, being approximately 15â¯Mgâ¯Câ¯haâ1 to a depth of 30â¯cm and 20â¯Mgâ¯Câ¯haâ1 to 100â¯cm. The 13C abundance data showed that the large gain in soil C was due to the slow decomposition of the forest-derived C (total loss 12.6â¯Mgâ¯Câ¯haâ1 over 16â¯years) and the large accumulation of C derived from the Brachiaria (total gain 43.2â¯Mgâ¯Câ¯haâ1). These results confirm the potential of productive Brachiaria pastures to accumulate soil C in a tropical climate with year-round rainfall.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
Camila A. dos Santos, Claudia de P. Rezende, Ãrika F. Machado Pinheiro, José M. Pereira, Bruno J.R. Alves, Segundo Urquiaga, Robert M. Boddey,