Effect of blended nps fertilizer and compost on growth And yield of quality protein maize (zea mays l.) At jimma, Southwestern Ethiopia

Abstract

Maize (Zea maize L.) is among the leading cereals in production globally and an important potential food security crop in Ethiopia. However, its productivity is very low mainly due to low soil fertility. Studies on the combined use of organic and inorganic fertilizers for maize are lacking at Jimma conditions. Therefore, a field experiment was conducted to determine the effect of combined application of NPS fertilizer and compost on yield and yield components of maize on Nitisols of Jimma Zone, Southwestern Ethiopia during 2017 main cropping season. The experiment involved factorial combinations of five rates of NPS fertilizer (0, 45.5 kg ha-1 blended NPS+31.2 kg ha-1 urea, 91 kg ha-1 blended NPS+62.4 kg ha-1 urea, 136.5 kg ha-1 blended NPS+93.6 kg ha-1 urea, 182 kg ha-1 blended NPS+124.8 kg ha-1 urea) and five rates of compost based on N-equivalence of recommended fertilizer rate (0, 2.3, 4.6, 6.9 and 9.2 ton ha-1 ) laid out in 5x5 factorial arrangements in RCB design with three replications. The N fertilizer equivalence value of applied compost at the rates of 2.3, 4.6, 6.9 and 9.2 ton ha-1 were 23, 46, 69 and 92 kg N ha-1 on dry weight basis, respectively. Data on the growth, yield and yield components of maize and some selected soil physico-chemical properties and nutrient uptake of crop were subjected to ANOVA using SAS version 9.3software. The results revealed that combined application of NPS fertilizer and compost significantly (P<0.05) affected days to 50% tasseling, 50% silking, days to 90% maturity, leaf area index, number of leaves per plant, stem girth, plant height, number of grains per row, grain yield and above ground biomass. However, number of ears per plant, ear length, number of grains per ear, ear diameter, thousand grain weight and harvest index were not affected by combined application of NPS fertilizer and compost. The highest grain yield (8453.2 kg ha-1 ) and above ground biomass (15387.2 kg ha-1 ) was obtained from combined application of 182 kg ha-1 blended NPS fertilizer+124.8 kg ha-1 urea and 9.2 ton ha-1 compost. Whereas, the lowest grain yield (2612.7 kg ha-1 ) and above ground biomass (5139.9 kg ha-1 ) was obtained from the control .Grain yield was increased by 223.54% over control and 24.1% over recommended NPS fertilizer. Partial budget analysis revealed combined application of 136.5 kg ha-1 blended NPS fertilizer +93.6 kg ha-1 urea with 6.9 ton ha-1 realized the maximum net return (40,925.46 birr ha-1 ) with marginal rate of return (1228.6%). The NPS fertilizer and compost rates affected nutrient uptake and most of the soil properties evaluated and there were changes in total N, available P and soil bulk density (compost rates only) after harvest. Nonetheless, this one season and location study has to be reconfirmed in different seasons and over locations in order to make sound recommendation.