Residual Effect of Permanent Manurial Trial on Soil Physical, Chemical and Biological Properties under Northern Dry Zone of Karnataka, India

Abstract

A field experiment was conducted at Regional Agricultural Research Station (RARS), Vijayapura, Karnataka, India, during kharif 2024-25. The study aimed to evaluate the residual effect of permanent manurial trial (initiated during 2017-18) on soil physical, chemical and biological properties established. Treatments comprised of unfertilised control (T1), sole inorganics (T2), 50% N through FYM + 50% through inorganic sources (T3), 50% N through Vermicompost + 50% through inorganic sources (T4), 50% N through sunhemp + 50% inorganic sources (T5), 50% N through Gliricidia loppings + 50% inorganic sources (T6) and 50% N through crop residues + 50% inorganic sources (T7). The experiment was laid out in randomised complete block design replicated thrice. In 2024, maize crop was taken as uniformilty trial without addition of manures and fertilizers. The study revealed that, the treatment receiving 50% N through FYM + 50% through inorganic sources (T3) significantly reduced soil bulk density, improved water holding capacity, soil organic carbon (SOC), available nitrogen, cation exchange capacity (CEC) and dehydrogenase activity followed by treatment receiving 50% N through Vermicompost + 50% through inorganic sources (T4). Across treatments, SOC and nutrient availabilities declined with soil depth, underscoring the dominance of surface-applied organics and root activity in topsoil layers. The investigation suggests that, Integrated Nutrient Mangemnet (INM) practices has long-term benefits in improving soil health and fertility in semi-arid vertisols.