Evaluation of Blended Fertilizer Formulas under Limed Condition of Acid Soil on Soybean (Glycine max) at Asossa District of Benishal-gul Gumuz Regional State

Abstract

Purpose: To evaluate the blended fertilizer formulas types, under unlimed limed condition of Asossa acid soil on soybean in Benishagul Gumuz of Ethiopia. Methods: Two factorial RCB design with three replications was used in the investigation. Five types of blended fertilizer formulas were tested under limed and unlimed condition in Factorial Randomized Complete Block Design. Lime and blended fertilizer types were used as factor. The amount of lime that was applied at each location was calculated on the basis of the exchangeable acidity, bulk density and 15 cm depth of the soil. One mole of exchangeable acidity would be neutralized by an equivalent mole of CaCO3. Accordingly, the amount of lime for this particular activity would be uniformly applied for all plots at 1.5 times of the exchangeable acidity (Equation 1) and incorporated in to the soil a month before seed sowing. Results: The effects of applied lime (CaCO3) and fertilizer types on growth and yield components of soybean were non-significantly (P>0.05) influenced except 100 seed weight, whereas the lime by blended fertilizer types interaction effects were not-significantly (P>0.05) affect all growth and yield components of soybean (Table 2). The highest plant height (71.58 cm) was obtained from NPKSZnB (Formula 5 modified) fertilizer type, however statistically non-significant from the other treatments. Conclusion: The partial budget analysis indicated that, it was not necessarily based on the highest marginal rate of return, rather based on the minimum acceptable marginal rate of return and the treatment with the high net benefit, relatively low variable cost together with an acceptable MRR becomes the tentative recommendation. Therefore we recommend the treatments (100 kg /ha NPSB) that have acceptable marginal rate of return, relatively high net benefit and relatively small total cost of production for soybean production in Asossa zone.