Integrated effects of reduction dose of nitrogen fertilizer and mode of biofertilizer application on soil health under mung bean cropping system

To study the integrated effects of reduced dose of chemical fertilizer with different methods and times of application of Rhizobium biofertilizer on soil health and fertility under mung bean (Vigna radiata) cropping, field experiments were carried out during three years (2009, 2010, and 2011) in West Bengal, India, in randomized block design. In the first year, varietal screening of mung bean under recommended dose of chemical fertilizer (20:40:20) were performed with five available varieties adapted to local climate. Reduced nitrogen fertilizer doses (20%, 30%, 40%, 50%, and 60%) and the recommended dose, as well as the Rhizobium biofertilizer application (basal, soil, and spray), were done, and data were recorded for pH, electrical conductivity, organic carbon, total nitrogen, total phosphorus, total potassium, and bacterial population of soil, both before sowing and after harvesting. The results indicated significant improvement in the soil quality with gradual buildup of soil macronutrient status after harvesting of crop. Application of biofertilizer has contributed significantly towards higher soil organic matter, nitrogen, phosphorus, and potassium. The use of biofertilizer significantly improved soil bacterial population count in the soil thereby increasing the soil health.