Soil organic carbon mineralization rates in aggregates under contrasting land uses

Abstract

Measuring soil organic carbon (SOC) mineralization in macro-aggregates (250-2000 μm), micro-aggregates (250-53 μm) and the < 53 μm fraction helps to understand how spatial separation of SOC inside soil aggregates regulates its dynamics. We hypothesized that (i) compared with macro-aggregates SOC mineralization rate of micro-aggregates would be slower, (ii) adsorption of SOC on < 53 μm fraction decreases the SOC mineralization rate, and (iii) land use has a significant influence on SOC decomposition rate. To test these hypotheses we collected topsoil from Dermosol (Acrisols in FAO Soil Classification) sites under three contrasting land uses namely native pasture (NP), crop-pasture rotation (CP) and woodland (WL).