Browsing by Author "Ramawatar Singh"
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ThesisItem Open Access Studies on Distribution and Mobility of Iron and Manganese down The Profile and Catena(Birsa Agricultural University, Ranchi, 1974) Ramawatar Singh; B.P.SrivastavaSeven soil profiles have been studied in two catenary sequence at Ranchi Agricultural College Farm, Kanke with a view to study the mobility of iron and manganese down the profile and catena. The morphological, physical, chemical and mineralogical properties as well as different forms of iron and manganese have been studied. The soils under study show a change in colour from yellow ish brown to brown in the well-drained soils and grey to olive in the some what poorly to poorly drained soils. Texture become heavier with depth and slope from sandy clay loan to clay. The amount of concretions increases with depth and is formed by alter nate vetting and drying in the subsoil. Mottlings are present in the poorly drained soils. Sand decreases with an increase in the clay content, Clay skins, slicken slides and gleyed spots are also observed in somewhat poorly to poorly drained profiles. Organic carbon and total nitrogen decrease with depth. C/N ratio increases with slope and decreases with depth. Mineralogical study indicates that the profiles under study are developed on granite gneiss parent rock. Quartz and feldspar are the dominant minerals. Generally the bottom land profiles are more chemically weathered. Topography has affected the mobility of nutrients in general and iron and manganese in particular in Chotanagpur auilu. It has been observed that total amount of these elements are concentrated in the lower horizons. The exchangeable or acid soluble forms are principally accumulated at the surface in thewell drained soils and in the B horizon under poor drainage. So on the basis of the soil development the profiles can be arranged as: Catena A, Profile Catena B, Profile IV> V VI > VII But on the basis of chemical weathering they can be rearranged as: Catena B, Profile VII 7 VI This differential behaviour of degree of chemical weathering and profile development is assigned to topography which has also affected the above properties of the soil. Mechanism for mobilizations of iron and manganese and their immobilization has been described. The formation of Red yellow light grey catenary soils of Ranchi Agricultural College, Farm has been explained on the basis of Mattsons' theory.