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.
