Quantitative Pedogenesis to Assess Soil Maturity vis-à-vis – Impact on Soil Quality in Easternghats of Odisha

Abstract

The present investigation is aimed at determination of various pedogenic indices to understand soil maturity in catenary sequence of varying physiographic confluences of Easternghats of Odisha occurring on Sambalpur and Koraput districts. Important pedogenic indices (PI) including redness rating (RR), relative profile development (RPD), relative horizon distinctness (RHD), sand/ silt, silt/ clay, CEC/ clay, index of weathering (Iw), exchangeable aluminium percentage (EAP) and ratios of dithionite-citrate extractable iron (Fed) and ammonium oxalate extractable iron (Feo) were used to assess soil maturity. Hierarchical clustering was employed to unfold varying degree of pedogenic processes across the geomorphic situations of the state. The physiographic confluence of Easternghats, Gahrjat Hills and Mahanadi Basin (Sambalpur district) represents formations of red ferruginous Alfisols in foot hills and uplands of granite-gneissic, quartzite and Khondalite (Typic Rhodustalfs) and in uplands of charnockite landscapes (Rhodic Paleustalfs) with high RR, RPD, RHD, EAP, (Fed-Feo)/ Fed and low sand /silt, silt/ clay, Iw and Feo/Fed attributing to rapid rate of pedogenesis with higher degree of maturity of soil profiles indicating to their relict nature i.e. paleoformations through progressive pedogenesis. Soils on inter-hill valleys, valleys and plains of any geologic formation revealed stagnated rates of pedogenesis indicated by gleyization with formations of Aquic Rhodustalfs, Aquic Haplustalfs, Oxyaquic Haplustalfs and Typic Endoaqualfs with low RPD, RHD, EAP and high Iw and Feo/Fed. Such an occurrence represents regressive pedogenic process under reduced conditions. Soil quality index (SQI) showed inverse relationship to pedogenic indices. Valleys and plains support promisingly crop diversification with high SQI and low PI, whereas, uplands and foot hills, representing the inverse characteristics, are being better promoted for agri-horticulture, agro-forestry and horti-silvicultural practices. The current research endeavor put an ample scope to upscale its inventory in similar physiographic and agro-climatic regions of the country.