Evaluation of carbon saturation level of Ferrosol and Dermosol under different land uses

Abstract

Fine soil particles especially silt + clay particles play important role in storing carbon (C). Thus the protective capacity of soils to store C is determined from relationship between % silt + clay content of soils and C associated on these particles. The difference between existing C content on silt + clay particles of soils and modelled protective capacity give an estimation of saturation level of that soil and are explained by using the term saturation deficit. Land use and land management influence on degree of saturation of protective capacity due to difference in C input and level of disturbance. The overall hypothesis of the research were (i) land use and soil properties influence the C saturation levels of soils (ii) soil organic carbon (SOC) mineralization will be higher from soils having lower silt + clay content and higher level of C saturation (iii) mean residence time (MRT) of SOC pool will be higher in soils having higher silt + clay and lower C saturation level (iv) carbon will be more protected within aggregates (< 2000 μm) compared to dispersed silt + clay (< 53 μm) and clay particles (< 2 μm) (v) stabilization of applied residue C will be higher in soils where protective capacity are less saturated with C (vi) desorption of indigenous soil C will be higher from soils having higher level of C saturation (vii) adsorption of added dissolved organic carbon (DOC) will be higher in soils having lower C saturation level.