Effects of organic manures and fertilizers on organic matter and nutrients status of the soil

Abstract

A long-term field demonstration was initiated in 1995 to evaluate the effect of organic manures (FYM, poultry manure and pressmud) and mineral fertilizers on changes of pH, electrical conductivity (EC), organic C and nutrient contents under pearl millet – wheat cropping sequence. Continuous application of organic manures alone or in conjunction with NP fertilizer for 10 years decreased the soil pH. However, a reverse trend was observed in case of EC. Organic C content of the soil decreased from its initial value, when only NP fertilizers were applied and increased significantly with the application of organic manures applied alone or with NP fertilizers. The highest organic carbon content of the soil has approached to 0.99% in plot receiving 15 Mg FYM +150 kg N +30 kg P₂O₅ ha⁻¹. The application of organic manures with or without NP fertilizers could not sustain the original level of N. However, their application increased the available P, K and DTPA extractable Zn, Fe, Mn and Cu content of soil. Application of P, K and micronutrients can be avoided with the application of organic manures. The build-up of organic C and nutrient contents was higher in surface soil as compare to sub-surface soil.

Keywords:

• Organic manures
• pH
• EC
• organic C
• NPK