Assessment of Nutrient Dynamics under Integrated Application of Inorganic, Organic and Biofertilizers in Red Loam Soil

Abstract

Integrated nutrient management (INM) was evaluated through a 60-day incubation experiment using red loam soil to assess temporal changes in available nitrogen (N), phosphorus (P), potassium (K), and sulphur (S). Soil samples were incubated with combinations of recommended or soil test-based inorganic fertiliser, farmyard manure (FYM), and a biofertiliser consortium, with sampling at 15, 30, 45, and 60 days after incubation (DAI). The treatments produced distinct nutrient-release patterns over time. Available N generally increased up to 30 DAI under sole inorganic fertilisation, whereas treatments combining inorganic fertilisers with FYM and biofertilisers maintained the increase up to 45 DAI before a slight decline. Available P increased up to 45 DAI in most treatments and then declined at 60 DAI, with higher values under treatments integrating FYM and the biofertiliser consortium. Available K increased continuously throughout the 60-day incubation period, particularly under integrated treatments. Available S increased during the early-to-mid incubation period and was generally higher under integrated or soil test-based nutrient treatments than under the control, with treatment-dependent declines later in the incubation. Overall, combining inorganic, organic, and biological nutrient sources influenced the timing and persistence of nutrient availability in red loam soil. These findings characterise the time-dependent release of major nutrients under controlled incubation conditions.