Investigation of response of upland rice (Oryza sativa L.) to blended NPSZnB fertilizer in Fogera and Libo Kemkem Districts of Amhara Region, Ethiopia

A field experiment was conducted for three years to determine economic optimum rate of NPSZnB blended + urea fertilizers for upland rice production in Fogera and Libokemkem districts of Amhara Region. Blended NPSZnB fertilizer rates of 100, 150, 200 and 250 kg ha-1 were factorially combined with 100, 150, 200 and 250 kg urea ha-1. Zero fertilizer as control treatment and recommended NP fertilizer as a reference treatment were included in the study. The treatments were laid in a randomized complete block design with three replications. The results indicated that the highest grain yields of 4 and 6 t ha-1 at Libokemikem and Fogera districts, respectively were obtained from 250 kg NPSZnB + 200 kg urea ha-1. The highest biomass yields at both districts were obtained from 250 kg NPSZnB + 250 kg urea ha-1. The partial budget analysis of the pooled data indicate that, at Libokemikem district, the maximum net economic return (NER) of Ethiopian Birr (Birr) 37,474.80 with marginal rate return of (MRR) 2617.5% was obtained from 250 kg NPSZnB + 200 kg urea ha-1. At Fogera district the maximum NER of Birr 62,548.60 with MRR 1214.6% was obtained from 100 kg NPSZnB + 250 kg urea ha-1. However, it is not possible to draw conclusions that the significant yield increment recorded was due to the contribution of S, B and Zn blends in the NPSB blended fertilizer. Because, there were confounding effects of N and P nutrients in the NPSZnB blended fertilizer. As it is revealed in the results, the significant yield response recorded, however, was due to the increasing levels of N. Therefore, we recommend further investigation of* the response of NERICA-4 (upland rice) to each nutrient (P, S, Zn and B) through nutrient omission studies.