Investigation of Response of Upland Rice (<i>Oryza sativa </i>L.) to Blended NPSB Fertilizer in Fogera and Libo Kemkem Districts of Amhara Region

Abstract

A field experiment was conducted for three years to evaluate and determine economic optimum rate of NPSB blended + urea fertilizers for upland rice production in Fogera and Libokemkem districts of Amhara Region. Blended NPSB fertilizer rates of 100, 150, 200 and 250 kg ha<sup>-1</sup> were factorially combined with 100, 150, 200 and 250 kg urea ha<sup>-1</sup>. Zero fertilizer as control treatment and recommended NP as a reference treatment were included in the study. The treatments were laid in a randomized complete block design with three replications. The results show that, in Libokemikem district, the maximum grain yield of 4.9 t ha<sup>-1</sup> was obtained from 200 kg NPSB + 250 kg Urea ha<sup>-1</sup>, while the maximum dry biomass yield of 10.2 t ha<sup>-1</sup> was recorded from 250 kg NPSB + 250 kg Urea ha<sup>-1</sup>. In Fogera district, the maximum grain and biomass yields of 6.1 and 15 t ha<sup>-1</sup>, respectively were obtained from 250 kg NPSB + 200 kg Urea ha<sup>-1</sup>. The partial budget analysis of the pooled data indicate that at Libokemikem district, the maximum net economic return (NER) of Ethiopian birr (Birr) 48,529.70 with marginal rate of return (MRR) of 1284.9% was obtained from 200 kg NPSB + 250 kg urea ha<sup>-1</sup>. At Fogera district, the maximum NER of Birr 62,323.60 with MRR of 959.7% was obtained from 100 kg NPSB + 250 kg urea ha<sup>-1</sup>. However, it is not possible to draw conclusions that the significant yield increment recorded was due to the contribution of S and B blends in the NPSB blended fertilizer. Because, there were confounding effects of N and P nutrients in the NPSB 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 and B) through nutrient omission studies.