Particle Size Distribution, Soil Organic Carbon Stock and Water Retention Properties of Some Upland Use System of Odisha and Assessing their Interrelationship

Abstract

Analyzed particle size distribution, soil water retention properties and organic carbon (SOC) stock of some upland cropping/land use systems of a watershed of Odisha (Kadalipal watershed, Dhenkanal, Odisha) viz., forest grazing land, maize, rice, groundnut, cucumber, okra, cowpea, cashew nut plantation and barren land and assessed their interrelationship. An overview of soil texture of the samples revealed that sandy clay loam texture constituted about 60% of all samples in different cropping systems and at different depths. Clay loam, sandy loam and loamy texture represented 20, 15 and 5%, respectively. Bulk density (BD) of surface layer ranged from 1.39 Mg m-3 in C7 (cashew plantations) to 1.48 Mg m-3 in forest grazing land (CO). The average clay content in the soil profile ranged from 23.8% in C0 (grazing land) to 32.6% in C6 (cowpea). The SOC at surface (0-0.15 and 0.15-0.30 m) layers were higher in forest grazing land (9.6 to 10.8 g kg-1) and inside cashew plantation (12.3 to 13.5 g kg-1) whereas, SOC was low in crop cultivated plots. Continuous tillage and cultivation of nutrient exhaustive crops might have favoured rapid rate of mineralization than that of accumulation of SOC in these fields. Among crop fields, legumes (groundnut, cowpea) hold promise for greater accumulation of SOC in the long-term. Soil water retention was found to be significantly correlated with SOC at 0-0.15 m depths only rather than the SOC of whole profile. Soil pH, BD, porosity had significant relationship (P< 0.05) with SOC content.