Shifts in soil organic carbon for plantation and pasture establishment in native forests and grasslands of South America
- 10 June 2012
- journal article
- research article
- Published by Wiley in Global Change Biology
- Vol. 18 (10), 3237-3251
- https://doi.org/10.1111/j.1365-2486.2012.02761.x
Abstract
The replacement of native vegetation by pastures or tree plantations is increasing worldwide. Contradictory effects of these land use transitions on the direction of changes in soil organic carbon (SOC) stocks, quality, and vertical distribution have been reported, which could be explained by the characteristics of the new or prior vegetation, time since vegetation replacement, and environmental conditions. We used a series of paired‐field experiments and a literature synthesis to evaluate how these factors affect SOC contents in transitions between tree‐ and grass‐dominated (grazed) ecosystems in South America. Both our field and literature approaches showed that SOC changes (0–20 cm of depth) were independent of the initial native vegetation (forest, grassland, or savanna) but strongly dependent on the characteristics of the new vegetation (tree plantations or pastures), its age, and precipitation. Pasture establishment increased SOC contents across all our precipitation gradient and C gains were greater as pastures aged. In contrast, tree plantations increased SOC stocks in arid sites but decreased them in humid ones. However, SOC losses in humid sites were counterbalanced by the effect of plantation age, as plantations increased their SOC stocks as plantations aged. A multiple regression model including age and precipitation explained more than 50% (p < 0.01) of SOC changes observed after sowing pastures or planting trees. The only clear shift observed in the vertical distribution of SOC occurred when pastures replaced native forests, with SOC gains in the surface soil but losses at greater depths. The changes in SOC stocks occurred mainly in the silt+clay soil size fraction (MAOM), while SOC stocks in labile (POM) fraction remained relatively constant. Our results can be considered in designing strategies to increase SOC storage and soil fertility and highlight the importance of precipitation, soil depth, and age in determining SOC changes across a range of environments and land‐use transitions.Keywords
This publication has 74 references indexed in Scilit:
- The hydrologic consequences of land cover change in central ArgentinaAgriculture, Ecosystems & Environment, 2012
- Grazing effects on belowground C and N stocks along a network of cattle exclosures in temperate and subtropical grasslands of South AmericaGlobal Biogeochemical Cycles, 2009
- Why does rainfall affect the trend in soil carbon after converting pastures to forests?: A possible explanation based on nitrogen dynamicsForest Ecology and Management, 2008
- Change in soil carbon following afforestationForest Ecology and Management, 2002
- Soil organic matter dynamics in density and particle size fractions as revealed by the 13C/12C isotopic ratio in a Cerrado's oxisolGeoderma, 2001
- Land use change and biogeochemical controls of nitrogen oxide emissions from soils in eastern AmazoniaGlobal Biogeochemical Cycles, 1999
- Organic matter dynamics and aggregation in soils under rain forest and pastures of increasing age in the eastern Amazon BasinGeoderma, 1997
- Soil properties under Amazon forest and changes due to pasture installation in Rondônia, BrazilGeoderma, 1996
- Organic carbon and 13C contents in soils and soil size-fractions, and their changes due to deforestation and pasture installation in eastern AmazoniaGeoderma, 1994
- Nature and behaviour of organic matter in soils under natural forest, and after deforestation, burning and cultivation, near ManausForest Ecology and Management, 1991