Significance of clay minerals in development of alluvial soils of Aravalli range.

Abstract

Fertile lands of eastern Rajasthan uplands are gradually declining their inherent capacity to the produce crops. A study has been conducted on alluvial soils; surrounded by Aravalli hills and deposited by Banas river. Different soils located over landforms with varied slopes and rainfall density and annual average rainfall were sampled for morphological, physico-chemical and mineralogical investigations. Present study is aimed to link the mineralogy of various size fractions and other physico-chemical characteristics as an evidence of pedogenetic process in development of alluvial soils. Our study indicates that the soils are coarser (sandy or sandy loam) in texture, consisting predominantly of quartz followed by feldspars and mica. Specific trend was not observed in minerals present in the clay matrix. Presence of unstable talc mineral in the clay fraction of soil over upper rolling plain indicates juvenile nature of soils.