The Effect of Sheep Manure Compost on Application Rate of Chemical Fertilizers in Grain Corn Planting

This study was conducted to evaluate the effect of sheep manure compost (direct and residual) combined with application of chemical fertilizer (N, P, K) in order to reduce application of chemical fertilizers and to obtain the optimum use of organic and chemical fertilizer in corn planted during 2002-2005 at Safi-Abad agricultural research center, Dezful. The experimental design was a completely randomized block with factorial arrangement. The treatments were at four levels of chemical fertilizers consisting of 50, 75, 100 and 125% of recommended rates on the basis of soil testing which were used from urea, triple super phosphate and potassium sulphate and four levels of sheep manure compost including of 0, 5, 10 and 20 t/ha. The results showed that the main effect of chemical fertilizers with the residual effect of sheep manure compost on grain corn, 1000-grain weight and uptake of N, P and K by grain were significant. Application of sheep manure compost increased soil organic carbon and available P and K significantly. Therefore, with regard to the condition of this experiment and economic analysis of the results, use of 50% chemical fertilizers (N, P, K) in combination with 5 t/ha sheep manure compost is recommended for corn production.