Carbon stocks and lability in land use and management systems in southwestern Goiás, Brazil

Abstract

The southwest region of the Goiás state, Brazil, is suitable for several agricultural activities, even in more fragile soils such as Typic Quartzipsamments. This study aimed to evaluate the carbon stocks and lability of a Typic Quartzipsamment under land use and management systems in southwestern Goiás. The experiment was conducted in a completely randomized design and consisted of areas subjected to five land use and management systems [native Cerrado vegetation (Brazilian Savanna), pasture under intensive grazing, pasture under extensive grazing, soybean and maize rotation, and eucalyptus]. Soil samples were collected at the 0-0.1 and 0.1-0.2 m layers. The land use and management systems affected the carbon stocks and quality. In the 0-0.2 m layer, the carbon stocks ranged between 15.9 and 29.2 Mg ha-1. The areas with eucalyptus and under intensive grazing promoted increases in the carbon stocks that ranged between 72 and 84 %, when compared to the areas with Cerrado vegetation and soybean and maize rotation. The carbon contents in the F1, F2 and F4 fractions were higher in the areas with eucalyptus and under intensive grazing. In the 0-0.1 m soil layer, the areas with eucalyptus and under intensive grazing had an increase in the carbon management index by 33 and 36 %, respectively, when compared to the reference area with native Cerrado vegetation.

KEYWORDS: Soil organic matter, carbon quality, carbon management index.