Soil Chemistry

The course presents basic concepts of soil science, with special attention to chemical, physical and biological processes that influence crop production and quality. What is a soil ? Mineral and organic constituents . Soil as an open system: profile formation, mass transfer into air and water. Soil as a multicomponent system: gaseous, solid and liquid phases. Soil minerals: parents materials and weathering products. Clays and oxides. Soil organic matter: elemental composition, plant derived biomolecules, humic substances. Types of humus. Carbon cycle. (2CFU) How soil can be described ? Physicochemical properties. Physical properties: texture, structure, real and bulk density, porosity. The interfacial relationship: adsorption and exchange. Surface charges, double layer theory, exchange reactions. Cation and anion exchange. Base saturation. Basics of water interactions in soil: water potential. Soil acidity: what is pH and how it is measured. Chemistry of acid soils and correction of soil acidity: lime requirement. Calcareous soils: effects on nutrient phytoavailability. Saline soils. Soil and nutrients (2 CFU). Biogeochemistry of soil nitrogen, and of soil phosphorus. The bioavailability concept. Influence of root and microrganisms on bioavailability. Evaluation of fertility status by soil analysis. Basics on soil sampling an on the main analitycal methodologies (1 CFU frontal lessons and 2 CFU lab and classroom activities).