Effect of different organic sources on nutrient dynamics and microbial count of black gram [Vigna mungo (L.) hepper]

Concerning fertilization, the pulse crops are more responsive to organic manures but indiscriminate and continuous use of chemical fertilizers has venomous effects on physical, chemical and biological properties of the soil thereby affecting the sustainability of crop production, besides causing environmental pollution.

The study aimed at understanding the effect of different organic amendments on nutrient dynamics of black gram (Vigna mungo), which was carried out at the IFS unit, College of Agriculture, Vijayapur, during Kharif-2019 to study the effect of different combinations of organic sources on nutrient availability, nutrient uptake and soil microbial load in black gram.

The application of vermicompost + ghanajeevamrutha @ 100% RDP + Rhizobium + PSB recorded significantly higher soil organic carbon (SOC) (0.70%), soil available nitrogen (291.39 kg ha^-1), phosphorus (36.30 kg ha^-1) and potassium (580.53 kg ha^-1) and significantly higher uptake of nutrients i.e., nitrogen (52.07 and 75.43 kg ha^-1), phosphorus (10.12 and 16.08 kg ha^-1) and potassium (37.67 and 55.42 kg ha^-1) at 45 and 75 DAS compared to all other treatments. Similarly, application of FYM + vermicompost @ 100% RDP + Rhizobium + PSB has recorded the highest microbial count of bacteria [24.40 × 10⁶ CFU (Colony Forming Units) g^-1], fungi (17.0 × 10³ CFU g^-1) and actinomycetes (7.50 × 10³ CFU g^-1), demonstrating the importance of usage of organics for improving the nutrient availability, uptake and microbial load in black gram.