Carbon Mineralization in Soil Aggregate Classes Under Leguminous Tree Planting in North Fluminense, Brazil

Abstract

The physical protection of soil organic matter through its occlusion in aggregates is a mechanism which reduces their accessibility by microorganisms. When the physically protected carbon (C) becomes accessible to the microbiota, it generates a flow of CO₂. The objective of this study was to evaluate the C mineralization rate in macro and microaggregates of macerated and non-macerated soils under different leguminous tree, pasture, and secondary forest (capoeira). The CO₂ mineralization curves showed that maceration increased the amount of C mineralized in macroaggregates, mainly in leguminous tree. Maceration provided an increase of approximately 50% and 47% in acacia and ingá, respectively, and 35% in sabiá. Capoeira and pasture did not respond to maceration.

Keywords:
microbial activity; physical protection; carbon lability; organic matter