Long-term Effects of Nutrient Management on Soil Health and Crop Productivity under Pearl Millet-Wheat Cropping System

摘要

An on-going long-term experiment under pearl millet-wheat cropping system was selected to investigate the effect of organic manures (FYM, poultry manure and pressmud) and fertilisers on the sustainability of pearl millet-wheat system. Application of organic manures (151 FYM or 7.5 t pressmud or 5 t poultry manure ha~(-1) yr~(-1)) alone resulted in poor yield of pearl millet and wheat crops. However, a significant increase in yield was obtained when organic manures were applied in conjunction with recommended dose of N for these crops and that was comparable with recommended dose of applied NP alone or NP applied in combination with organic manures. Continuous application of organic manures alone or in conjunction with NP fertiliser for 16 years of pearl millet-wheat cropping system decreased the soil pH. However, an increase in EC was also observed. Organic C content of soil decreased from its initial value, when only NP fertilisers were applied and increased significantly with the application of organic manures applied alone or with NP fertilisers. Application of organic manures with or without NP fertilisers could not sustain the initial level of N. However, their application increased the available P, K and DTPA extractable Zn, Fe, Mn and Cu content of soil. The soil fertility with respect to P, K and micronutrient (Zn, Mn, Fe and Cu) can be maintained with the application of 151 FYM or 7.5 t pressmud or 5 t poultry manure ha"1 yr1. Thus, application of P, K and micronutrients fertilisers can be avoided with the application of organic manures. About 17.0, 20.6 and 18.6% of organic C was retained in soil during the period of 16 years added through FYM, poultry manure and pressmud, respectively, under pearl millet - wheat cropping system. The build-up of organic C and nutrient contents was higher in surface soil compared to sub-surface soil.