Effect of organic materials on grain yield and soil properties in maize (Zea mays)-wheat (Triticum aestivum) cropping system

A field experiment was conducted during 1994-95 and 1945-96 to evaluate som e locally available organic plant residues as supplementry source of nutrie nts in maize (Zea mays L.)-wheat (Triticum aestivum L. emend. Fiori & Paol. ) cropping system. Grain yield, nutrients uptake by maize increased signifi cantly with increase in levels of NPK. Response to 100% NPK was 1.51 and 1. 36 tonnes/ha over control yield of 1.87 and 1.62 tonnes/ha in maize and whe at crops respectively. Integration of 75% N through chemical fertilizers 25% N through organic sources gave equal yield to 100% NPK in maize. The fa rmyard manure and white popinac leaves had registered their residual effect on succeeding wheat crop by producing equivalent yield as 100% NPK Among d ifferent organic sources, farmyard manure proved superior to blackgram (Pha seolus mungo L.) straw followed by white popinac leaves while wheat straw p roved inferior source of N substitution. The water-holding capacity, organi c carbon, available nitrogen and phosphorus increased with increase in the organic residues while available K and bulk density decreased. The values w ere more evident in integration of 50% N from chemical fertilizer + 50%N th rough organic sources, viz farmyard manure, white popinac leaves and blackg ram straw.