ISSN 2360-7971
Soil fertility depletion and soil acidity are critical problems for crop production in western Ethiopia. Therefore, a field experiment was conducted on the Nitisols of the Asossa Agricultural Research Centre to characterise the soil fertility status of the farm and investigate the response of yield and yield components of maize (Zea mays L.) to different blended fertiliser rates and types. The treatments consists of: control, three rates of N and P combined (92/46, 115/57 and 138/69 N/P2O5 kg ha-1 and two formula of blended fertilizers with different rates, formula 2 consists of 100 kg NPSB+ 73.9 N,150 kg NPSB +110.8 N and 200 kg NPSB + 147.8 N kg ha-1 and formula 4 consists of 100 kg NPSZnB + 75.1 N, 150 kg NPSZnB + 112.6 N 1 and 200 kg NPSZnB +150.2 N kg ha-1. The treatments were laid out as a randomised complete block design with three replications. To characterise the experimental area soil, two pedons were opened from cultivated and uncultivated adjacent plots. The experimental soil was strongly acid to moderately acidic in pH, had vcarbon, was mediumrganic carbon, to very low in total nitrogen, was below the critical level of available P (Olsen extractable), and had high CEC. Application of blended fertilisers (NPSB, NPSZnB) hastened days to tasseling, silking, and maturity by 10, 7, and 15 days, respectively, as compared to combined N and P rates. Application of blended fertiliser significantly (p < 0.01) increases the plant height, cob weight, ear length, 100 kernels weight, number of kernels per row, and ear height as compared to combined N and P and the control. The analysis of variance revealed that fertiliser types and rates significantly (P < 0.01) affected biomass yield, grain yield, straw yield, and harvest index. However, there was no significant difference between the two blended fertiliser types. Maximum grain yield (7056.2 kg ha-1) was recorded with 200 kg NPSZnB + 150.2 N kg ha-1 application, while minimum grain yield (2996.0 kg ha-1) was recorded from the control treatment. The application of 150 kg NPSB + 110.8 N kg ha-1 had the highest marginal rate of return (MRR%) and net benefit. Therefore, we recommended the treatment (150 kg NPSB + 110.8 N kg ha⁻¹) since it produced a high marginal rate of return, a high net benefit, and a relatively small total cost of production for maize production in the Asossa area.
Keywords; Blended, pedons, yield, uptake, efficiency, recovery, net benefit