ABSTRACT
Soil is basically the material formed at the atmosphere, rock or sediment interface on the Earth, being largely affected by plant chemical action. Deep-rooted higher plants brought about an acceleration in the rate of production of soils through concomitant processes of mineral weathering and the deposition of plant products, including exudates and litter, to produce organic matter following processing by microorganisms. Vascular deep-rooted plants also played an important physical part in the sustained development of soils. Weathering literally occurs when minerals in or from rocks are exposed to the weather at Earth–surface conditions. The formation of the initial soil layer on a rock permits the retention of water which interacts with the rock and continues to produce new minerals such as silicate clays. The fine-grained clays in the soil zone are formed by reworking alterite zone minerals and transforming them chemically to a certain extent.
