Substitution of Inorganic Nitrogen with Organic Amendments for Improvement of Soil Properties, Microbial Community, and Enzymatic Activity in Maize-Wheat Cropping System Under Sub-temperate Ecology

Integrated nutrient management (INM) comprised of farmyard manure (FYM) and chemical fertilizers augmented soil fertility in terms of nutrient availability and microbial activity. Combined application of different sources of nutrient has positive effects on soil health; however, potential of INM has still to be explored along with newly introduced natural formulations i.e., Jeevamrit and Beejamrit.

Hence, the present study (2019–2021) aims to reduce 50% inorganic nitrogen (N) with organic amendments and its effect on soil health laid out in a randomized complete block design replicated three times with seven treatments, viz. 10 t ha⁻¹ FYM + 5% Jeevamrit, 10 t ha⁻¹ FYM + 10% Jeevamrit, 50% N + 10 t ha⁻¹ FYM + 5% Jeevamrit, 50% of N + 10 t ha⁻¹ FYM + 10% Jeevamrit, Beejamrit + 5% Jeevamrit, Beejamrit + 10% Jeevamrit, 100% recommended dose of fertilizers (RDF).

The bulk density, soil organic carbon, microbial population, enzymatic activities, and nutrient availability were determined in the 0–15 cm soil layers. The treatment 50% N + 10 t ha⁻¹ FYM + 10% Jeevamrit improved the soil bulk density, soil organic carbon, soil organic carbon sequestration, bacterial and fungal population, enzymatic activities, primary (N, P, K) as well as secondary (S, Ca, Mg) nutrients, and micronutrients (Fe, Cu, Mn). Comparatively higher fungal population, total porosity, and water holding capacity were observed in Beejamrit + 5% Jeevamrit than 100% RDF, while electrical conductivity was higher under 100% RDF. Soil pH was reduced under 100% RDF and numerically higher values of Zn and B were observed in 50% N + 10 t ha⁻¹FYM + 10% Jeevamrit.

Therefore, the integrated use of nutrients in our study may help to replace 50% of N from inorganic fertilizers with higher nutrient availability, microbial load, and enzymatic activities in the rhizosphere.