Soil Stabilization in Semiarid and Arid Land Agriculture

Soil and water conservation is essential for sustaining food production and for preserving the environment. This review considers the potential of four types of soil amendments, namely gypsum, organic polymers, organic matter waste materials, and fly ash, as soil stabilizers. Addition of gypsum to soil can limit clay swelling and dispersion, and thus improve soil structural stability, by both soil solution electrolyte effects and cation-exchange effects. Synthetic organic polymer addition to soil surface aggregates leads to their stabilization, improved bonding between adjacent aggregates, and clay flocculation. Organic matter, also used for promoting aggregate stabilization, enhances soil microbial activity that transforms the newly added organic matter into polysaccharides and long chain aliphatic compounds capable of binding and stabilizing aggregates. Fly ash additives can improve soil physical characteristics including texture, structure, water holding capacity, hydraulic properties, and aeration. However, fly ash has a number of inherent qualities that under certain circumstances may limit its usefulness for soil stabilization, and which may even result in increased erosion and soil loss.