A field experiment was conducted to study the direct and residual effects of zinc-enriched organic manures in maize-sunflower cropping system. Sources of organic manures viz., farmyard manure, poultry manure, coir pith and biogas slurry alone as well as enriched with zinc @ 0, 12.5 and 25.0 kg ZnSO4 ha−1, were applied to the maize crop @ 1 t ha−1. Sunflower was raised as the residual crop without disturbing the existing layout and evaluated for the residual effect. The results revealed that irrespective of the manure sources, the seed and stalk yield of sunflower was significantly influenced by the residual effect of zinc enriched manure application. The seed yield of sunflower significantly increased to a tune of 15 per cent over control for residual effect of zinc sulphate application at 25 kg ha−1 while for that of manures, yield increase was to a tune of 12 per cent over control. Among the manures poultry manure was superior and recorded the highest uptake of Zn by sunflower seed for the residual effect followed by biogas slurry. The persistence of residual effect confirmed the fact that zinc application to each crop is not necessary in case of zincenriched manure application.
