Soil organic carbon, dehydrogenase activity, nutrient availability and leaf nutrient content as affected by organic and inorganic source of nutrient in mango orchard soil

Changes in soil organic carbon, dehydrogenase activity, nutrient availability and leaf nutrient concentrations in a mango orchard soil was evaluated from four years (2007-2011) field experiment on a Typic Ustocrepts soil of subtropical region in Lucknow, India. Organic (FYM, vermicompost, mulching, Azotobacter, PSM and Trichoderma harzianum) and inorganic (N, P, K) substrates were applied each year within the tree basin. It was observed that soil and leaf nutrients concentrations significantly increased in organic and inorganic amended soils as compared to control. Vermicompost, organic mulching and microbial inoculation significantly enhanced soil organic carbon content, available nutrients, dehydrogenase activity and leaf nutrient concentrations. Dehydrogenase activity was highest (1.85 ìg TPF g-1 h-1) in organically treated soils. Surface soil (0-10 cm depth) showed higher dehydrogenase activity (1.29 to 1.85 ìg TPF g-1 h-1) as compared to lower soil depths in all the treatments.