Abstract:
Production and productivity of common bean is decreased mainly by soil fertility depletion,
inappropriate rate of poor nutrients availability and application without soil test, and
inefficient crop response. Crop specific fertilizer recommendation is necessary for sustainable
crop production. Accordingly, a field experiment was conducted during the main rainy season
of 2019 to evaluate the effects of types and rates of blended fertilizers on selected soil
chemical properties and yield and yield components of common bean at Jinka Agricultural
Research Center in Debub Ari district, Southern Ethiopia. The experiment consisted of 11
treatments viz. control (without any fertilizer), RNP (64N and 46P2O5), 100 kg NPS, 150 kg
NPS, 200 kg NPS, 100 kg NPSB, 150 kg NPSB, 200 kg NPSB, 100 kg NPSZnB, 150 kg
NPSZnB, and 200 kg NPSZnB ha-1 blended fertilizers. Muriate of Potash containing 0-0-60
was applied at planting in all treatments except the control plot. The experiment was laid out
in Randomized Complete Block Design with three replications. Soil samples were collected
from the experimental field (0-20 cm depth) before planting and after harvest to determine
selected soil properties. After harvesting, the crop was partitioned into straw and grain for the
determinations of N, P, and K concentrations, uptakes, and calculation of N and P fertilizer
recoveries and use efficiencies. The experimental soil is sandy loam in texture, slightly acidic
in reaction, very low in organic carbon, low in total nitrogen, low in available P, low in
available K, medium in available B, and low in available Zn, medium extractable S, and
moderate in CEC. The analysis of variance showed that the application of blended fertilizers
were significantly (p < 0.05) increased most yield and yield parameters of the common bean
compared to the control plots. The maximum grain yield (3477.0 kg ha-1) was obtained from
the application of 200 kg ha-1of NPSB followed by the treatment of 200 kg NPSZnB, 150 kg
NPSB, 150 kg NPSZnB and 200 kg NPS ha-1 while the minimum (1857.9 kg ha-1) was obtained
from the control. The result indicated that nutrient content and uptake by common bean
increased when the blended fertilizer rates increased. The application of 150 kg NPSB ha-1
had maximum and acceptable Marginal rate of return (MRR %) and net benefit. Therefore,
this type and rate of blended fertilizer (150 kg NPSB ha-1) can tentatively be recommended
since it produced a high marginal rate of return, high net benefit, and relatively low total cost
of production, for common bean production in the study area
