ASSESSMENT OF CARBON POOLS IN PADDY UNDER VARIOUS GROWING PRACTICES OF UPLAND AND LOWLAND PADDY FIELDS

Abstract

A field experiment was conducted during 2018–19 to evaluate the carbon pools in paddy soils managed under different upland and lowland rice-growing practices. The study was undertaken in four villages of Parseoni taluka in Nagpur district. A total of 30 farmers practicing five distinct rice production systems—conventional lowland, organic lowland, integrated nutrient management (INM) lowland, conventional upland, and INM upland-were selected for the study. Soil samples collected at the maturity stage of paddy were analyzed for inorganic carbon, organic carbon and different labile carbon fractions, viz., cold-water-extractable organic carbon (CWOC), hot-water-extractable organic carbon (HWOC) and readily oxidizable carbon (ROC). The results revealed considerable variation in carbon pools among the different growing practices. Organic carbon content ranged from 5.15 to 6.28 g kg⁻¹, with the highest value recorded under organic lowland practice (6.28 g kg⁻¹) and the lowest under conventional upland practice (5.15 g kg⁻¹); however, the differences were statistically non-significant. Cold-water-extractable carbon varied from 28.47 to 52.40 mg kg⁻¹, with the maximum value under organic lowland and minimum under INM lowland practice. Hot-water-extractable carbon ranged from 53.34 to 66.20 mg kg⁻¹, with the highest value observed under organic lowland and the lowest under INM upland practice. Readily oxidizable carbon showed a range of 116.98 to 194.76 mg kg⁻¹, with the highest value recorded under organic lowland and the lowest under conventional lowland practice. Inorganic carbon also varied among the growing practices, with comparatively higher values under upland conditions