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.