Assessment of soil carbon and biochemical indicators of soil quality under rainfed land use systems in North Eastern region of Punjab, India

The changes in land use systems result in remarkable variations in SOC and its dynamics which subsequently govern soil biochemical processes, microbial and metabolic indices in soil. The detail understanding about the responses of different C pools to land uses is essential for maintaining the soil quality. The present study was undertaken in six rainfed land use systems of north eastern Punjab, India comprising of agriculture, horticulture, agri-horticulture, forestry, agroforestry and barren lands. The soil samples (0-15 cm) were collected and analyzed for soil carbon fractions and biochemical activities. The oxidisable carbon fractions i.e. very labile carbon, labile carbon, less labile carbon, recalcitrant carbon and total organic carbon contents in soil varied significantly from 0.09%-0.22%, 0.09%-0.23%, 0.02%-0.15%, 0.15%-0.72% and 0.83%-4.68%, respectively. The soil dehydrogenase activity, soil microbial biomass carbon, metabolic and microbial quotients showed significant variations and ranged from 5.4 -10.9 mu g TPF g(-1) soil h(-1), 34.9 -184.5 mu g g(-1)soil, 0.0011-0.0034, 45.0-195.5, respectively. Agri-horticulture and forestry system were observed to be best environment friendly and sustainable system in rainfed regions. Carbon management index (28.9%), metabolic potential (9.8%) and total organic carbon (5.4%) were three topmost soil quality indicators for soil health in rainfed land use systems.