Long-term Effects of FYM and N on Soil Health and Crop Productivity under Pearl millet - Wheat Cropping System

摘要

A long-term field experiment was initiated in October, 1967 to study the response of fertiliser N to pearl millet - wheat cropping system at various levels and modes of farmyard manure (FYM). The results indicated the superiority of integrated use of FYM and fertiliser N in increasing the productivity of pearl millet - wheat cropping system compared to application of fertiliser N alone. Both pearl millet and wheat crops responded linearly up to 120 kg fertiliser N ha~(-1) at FYM levels ranging from 0 to 45 Mg ha~(-1). Application of FYM in both the seasons (Kharif and Rabi) gave maximum yield followed by its application in Rabi or Kharif season alone. However, application of FYM in Rabi (winter) season was found to be more beneficial than its application in Kharif (rainy) season. The organic C, available N, P, K, S, Zn, Mn, Fe and Cu contents of soil changed distinctively during 37 years of experimentation. Continuous application of FYM for a period of 37 years improved organic C, available P, K, S, Zn, Mn, Fe and Cu content of soil. Soil fertility with respect to P and K can be maintained with the application of 15 Mg FYM ha~(-1) year~(-1) to their original contents but not for N. Application of P and K fertilisers can be avoided with the application of 15 Mg FYM ha~(-1) year~(-1) with 120 kg fertiliser N ha-1 in a pearl millet - wheat cropping system. It has been predicted that for each unit (0.1%) increase in soil organic C, the productivity of pearl millet can be increased by 273 kg ha~(-1) and that of wheat by 1591 kg ha~(-1). Application of FYM improved the hydraulic conductivity, infiltration rate, water stable aggregates, moisture retention capacity and mean weight diameter and reduced bulk density and dispersion percentage of soil. Increasing levels of FYM from 0 to 45 Mg ha~(-1) increased all fractions of C, N, P, K, S, Zn, Mn, Fe and Cu in soil. In this paper the importance and beneficial role of FYM in combination with fertiliser N for sustainable soil health and crop productivity under pearl millet-wheat cropping system has been discussed.