Integrated Fundamentals of Soil Science: Processes, Properties and Sustainable Management

Soil chemical properties regulate nutrient availability, contaminant mobility, microbial transformations, salinity development and organic matter persistence. This chapter synthesises the principal chemical attributes of soils, with emphasis on soil reaction, buffering capacity, electrical conductivity, salinity, colloidal surfaces, ion exchange and organic matter chemistry. Soil pH is presented as a central diagnostic property because it influences nutrient solubility, microbial activity, mineral weathering and the behaviour of potentially harmful elements. Buffering capacity is explained through carbonate, cation exchange, aluminium hydrolysis and organic matter functional group systems, highlighting its relevance to lime requirement and soil management. Electrical desorption processes. Cation and anion exchange are considered in relation to nutrient retention, base saturation, phosphate fixation and contaminant movement. Finally, the chapter reviews contemporary understanding of soil organic matter fractions, including particulate organic matter, mineral-associated organic matter and pyrogenic carbon, with attention to their roles in carbon persistence, nutrient cycling and soil function under changing environmental conditions. Conductivity and salinity are discussed in relation to osmotic stress, sodicity, saltwater intrusion and the management of salt-affected soils. The chapter also examines inorganic and organic colloids, including clay minerals, iron and aluminium oxyhydroxides, allophane, imogolite and humic substances.