Assessment of soil biochemical properties and soil quality index under rainfed land use systems in submontane Punjab, India

Abstract

The conversion of natural systems to cultivated systems contributes to changes in the activities of microbial communities and biochemical processes in the soil. A total of 80 surface soil samples (0-15 cm) from 6 rainfed land use systems viz. agriculture, horticulture, agri-horticulture, forest, agroforestry and eroded lands were analyzed for biochemical properties and to derive soil quality index. The soils are slightly acid to neutral in reaction (pH-6.4-6.9) with 0.09-0.23 dS m−1 electrical conductivity (EC), loamy sand to sandy loam in texture, 1.4-6.1 g kg−1 soil organic carbon (SOC), 86-406 kg ha−1 available nitrogen, 29.3-32.6 kg ha−1 available phosphorus,65-226 kg ha−1 available potassium,10.3-21.3 mg kg−1 DTPA-Mn, 12.1-34.2 mg kg−1 DTPA-Fe, 0.34-1.01 mg kg−1 DTPA-Cu and 0.76-1.15 mg kg−1 DTPA-Zn, respectively under different land use systems. Among soil biochemical properties, the enzymic activity among land use systemsis varied from 7.4 to 12.8 µg TPF g−1 h−1 for dehydrogenase activity, 22.3 to 34.5 µg pNP g−1 h−1 for acid phosphatase, 43.4 to 60.1 µg pNP g−1 h−1 for alkaline phosphatase, 3.31 to 4.77 µg NH4-N g−1 soil min−1 for urease activity-, basal soil respiration −0.13 to 0.30 µg CO2 g−1 soil h−1 for basal respiration , 46.5 to 242.6 µg g−1 soil for soil microbial biomass carbon (MBC) and 8.68 to 30.6 g kg−1 for total easily extractable glomalin (TEGP), respectively. The principle component analysis showed that SOC, EC, TEGP, MBC and DTPA-Zn are robust soil quality indicators under different land use systems in submontane Punjab. The forestry system has higher values for physicochemical, biochemical properties and soil quality index as against agri-horticulture, horticulture, agroforestry, agriculture and eroded system. In subsystems, eucalyptus-based forestry and mango based agri-horticulture systems are served as a better system for soil quality assessment in submontane Punjab, India.