Effect of Soil Management on the Formation, Prevention and Control of Surface Crusts

Surface Soil crusting (SSC) is global phenomena that occur in variety of soil types and conditions prevalent in agricultural lands. The physical degradation results in a low hydraulic conductivity with problems of runoff and erosion and reduction in crop production due to reduced water infiltration and seedling emergence. Several factors influence the type and properties of soil crusts. These include surface roughness, soil water content, slope angle, topographic position, rainfall intensity, and crop cover. The SSC are generally divided into three main types, viz., structural crusts, sedimentional crusts, and Biological soil crusts. Soil crusting causes specific modification to the physical or structural properties of the soil surface. It causes decrease in steady - state water infiltration, induces soil erosion and soil degradation, physical impedance in seedling emergence and poor root growth, poor soil aeration in rhizosphere, affects nodule formation, frequent tillage requirement and delay in farm activities. Therefore, crusts decrease infiltration, accelerate ponding and runoff, causes inefficient irrigation and soil erosion. Soil aggregate stability is probably the single most important property affecting the rate of crust formation and final crust properties. Management of surface crusts can be best achieved by combining strategies that address both the physical processes of aggregate disintegration due to raindrop impact and the chemical process of dispersion. Anthropogenic soil crusting causes desertification and impedes vegetation establishment. Although surface crusting has been the subject of considerable research over the past 50 years or more, the practical management of soil crusts remains a challenge for many dryland communities.