Biogeochemistry of Soil Organic Matter

Benefits of MOS in conservation management systems:Physical (structure and aggregation) forming larger structures that favor the root system of cultivated plants.Chemical: By improving the CEC of soils, complexing exchangeable aluminum and reducing the adsorption of P. This is especially helpful in Brazil's tropical soils.Biological: Promotes soil microbiota and enzymesSoil management involving mechanical intervention (plowing, harrowing, scarification, etc.) breaks up soil aggregates, macro- and micro-aggregates, increasing the area of exposure of MOS to microbial attack. In addition, with greater aeration, micro-organisms attack this MOS more easily and contribute to its mineralization. Grass residues have a higher C/N ratio, often above 30/1, which is why the balance between immobilization and mineralization tends towards microbial immobilization, until this C/N ratio becomes narrower, at which point this balance will tend towards mineralization. Soybean waste has a narrower C/N ratio, below 20/1, which makes mineralization the predominant process.