Abstract:
Low soil fertility and limited nutrient supply is one of the causes for low teff production and
productivity at national level and in the Tembaro district. The overall objective of this study was,
therefore to evaluate different rates of mineral fertilizer to optimize teff yield in Tembaro district.
To realize this objective, a field experiment was conducted during the main cropping season of
2018. The treatments consisted of factorial combinations of control, five DAP and urea rates (50
kg DAP+50 kg urea/ha, 75 kg DAP+75 kg urea/ha, 100 kg DAP+100 kg urea/ha, 125 kg
DAP+125 kg urea/ha and 150 kg DAP+150 kg urea/ha) and five rate blended fertilizers,
containing different proportions of N, P, S and B (61kg NPSB +44.5 kg urea/ha,91.5 kg
NPSB+66.75kg urea/ha,122 kg NPSB+89 kg urea/ha,152.5 kg NPSB+111.25 kg urea/ha and 183
kg NPSB+133.5 kg urea/ha. The experiment was laid down in Randomized Complete Block
Design with four replications on farmer’s field. Accordingly, the soils have pH of 5.33-5.42,
with44-46% clay, 28-32% silt and 28-32% sand, 0.119-1.3% TN,13.94-15.22mg/kg available
S,8.21-9.11mg/kg available P,0.71-0.75mg/kg available B,0.96-1.2% OC,1.66-2.07% OM,5.7-
6.8cmol(+)/kg Exchangeable Ca,2.9-2.3cmol(+)/kg Exchangeable Mg,0.79-0.81cmol(+)/kg
Exchangeable K,0.06-0.09cmol(+)/kg Exchangeable Na, 49.7-50.6% PBS and 19.8-
23.6cmol(+)/kg CEC at (Semen Ambukuna) and (Belela) experimental sites, respectively before
sowing. The textural class of soil at both experimental sites was clay. Generally, one year mineral
fertilizer application blended (NPSB) plus urea and DAP plus urea fertilizers) may be slightly
decrease the soil fertility status both experimental area after harvested except available P soil
slightly increased in both experimental sites as compared to before sowing. Effect of fertilizer
was also significant (p<0.05) for all growth parameters, yield, yield components, except total
number of leaves. Fertilizer and location interact to significantly affecting 90% maturity, leaf
area, number of tillers and apparent recovery efficiency of P. The maximum grain yield of teff
(2426kg/ha) was recorded for183kg NPSB+133.5kg Urea/ha and statistically similar with
application of 100kg DAP+100kg urea/ha and 152.5kg NPSB+111.3kg urea/ha, while the
minimum value (470.8kg/ha) was obtained from the control plots at study area. The maximum
mean grain yield (1655.28kg/ha) was obtained at Belela, while the lowest mean yield
(1596.72kg/ha) was recorded at Semen Ambukuna. Therefore, recommended the treatment (100
Kg DAP + 100 kg ha-1) since it produced high marginal rate of return and relatively small total
cost of production, for teff production in Tambaro area. Furthermore, based on yield, net benefit
and relatively low total cost of production the farmer of Tambaro area also can use 152.5 kg
NPSB + 111.3 kg urea in case of absence of DAP in market. However, it was suggested that
further research across all soil types, in different years and locations may be required to draw a
sound recommendation for teff production in the area. This study provides insights for
smallholder farmers to incorporate recommended rate of N and P fertilizer for soil fertility
amendment for boosting teff production.