Influence of agricultural practices on the dynamics of carbonates in soils

Abstract

Despite being an important stock of carbon in soils, soil inorganic carbon (or SIC) has been largely underestimated compared to soil organic carbon (SOC). The main arguments for this are the supposed little variation in its content in soils after thousands of years. However, recent studies have recorded changes in the SIC pool over decades because of agricultural practices. The SIC forms most of the C in arid and semi-arid regions, which have a key role in the global C cycle, since the conversion to agricultural lands will generate processes of accumulation and/or dissolution of SIC. This review aims to analyse scientific investigations related to carbonates in the soil, seeking to know the influence of agricultural practices, recommended irrigation, fertilization and tillage on SIC reserves, to elucidate the dominant processes and their possible effect on the current climate change scenario. The results indicate that fertilisation and the use of pH correctors have a direct effect on the elimination of carbonates and the potential to release enormous amounts of CO₂ into the atmosphere in the medium term. However, the information collected regarding irrigation and tillage is not enough to conclude which is the dominant process, nor to calculate the sequestration or release rates of C.