International Journal of Plant & Soil Science

West Bengal is characterised by a predominance of acidic soils, with more than 70% of the cultivated soils exhibiting acidic reactions and relatively high concentrations of Fe and Al. Under such soil conditions, molybdenum (Mo) availability is often restricted, which can adversely affect legume productivity. The yield of kharif black gram in the region remains considerably lower than the national average, partly owing to micronutrient limitations. Therefore, an experiment was conducted to evaluate the response of black gram variety PU-13 to different methods and levels of Mo application. The experiment was carried out at the Mondouri Farm of Bidhan Chandra Krishi Viswavidyalaya using an acidic, sandy loam soil with a light texture and relatively low fertility. The soil was characterised by appreciable levels of Fe, Mn and Al and inadequate Mo availability. Four rates of Mo were applied to the soil (0, 0.25, 0.5 and 0.75 kg ha⁻¹) in combination with two foliar concentrations, namely 0.1% (F1) and 0.2% (F2), to assess their effects on crop growth, yield components and nutrient uptake.

The results demonstrated that increasing the concentration of foliar-applied Mo enhanced the growth and yield-related characteristics of black gram. A similar positive response was observed when foliar application was combined with soil application of Mo. However, the beneficial effect was observed only up to the application of 0.25 kg Mo ha⁻¹ to the soil in combination with a 0.2% foliar spray. Beyond this treatment level, a decline in the measured growth and yield attributes was recorded. The maximum grain yield of 549 kg ha⁻¹ was obtained with the combined application of 0.25 kg Mo ha⁻¹ to the soil and a 0.2% Mo foliar spray. Molybdenum application also positively influenced the uptake of the major nutrients, particularly N, P and K. The greatest nutrient uptake was recorded under the S₃F₂ treatment combination. Post-harvest soil analysis further indicated an improvement in soil fertility status, with a positive NPK balance remaining in the soil after accounting for crop nutrient removal. Overall, the findings indicate that integrating soil and foliar application of Mo can improve the performance and nutrient utilisation of black gram cultivated under acidic, Fe-rich and low-fertility soil conditions. Among the treatments evaluated, the combined application of 0.25 kg Mo ha⁻¹ to the soil together with a 0.2% foliar spray proved to be the most effective treatment for maximising black gram productivity under the experimental conditions.