Integrated effect of organic and inorganic manuring on yield sustainability in long-term fertiuzer experiments

Incorporation of farmyard manure @ 10–15 t ha⁻¹ yr⁻¹ with recommended NPK fertilizer doses to the kharif crop in the sequence in long term fertilizer experiments of ICAR has a pronounced effect in enhancing the efficiency of chemical fertilizers. The cropwlse pooled. results over 25 years have indicated significant improvements in crop productivity with the integrated use of organic and inorganic fertilizers by 11 to 44 and 15 to 26 per tent, respectively over optimal (100% NPK) and superoptimal (150% NPK) levels of chemical fertilizers at most of the locations. Beneficial residual effect varying between 11 to 31 per cent has also been observed on the succeeding crop in the sequences in different soil groups. In addition to the sustainable yield gains, use of organic manure has also significantly increased the availability of the limiting nutrients in the soil and thus maintained the fertility of different soils.