Effect of Blended NPSZnB Fertiliser Rates on Growth and Yield of Tef [Eragrostis tef (Zucc.) Trotter] Varieties in Haro Limmu District

Tef (Eragrostis tef (Zucc.) Trotter] is one of the most important cereal crops and predominant staple food in Ethiopia. However, its productivity is constrained by a number of problems, lack of site-specific fertilizer recommendation and high yielding varieties are crucial in the study area. Hence, a field experiment was conducted during 2020 main cropping season to identify most productive variety and determine most economically feasible blended NPSZnB fertilizer rate at Farmers Training Center in Ucha Kebele, Haro Limmu district. The experiment included five different NPSZnB fertilizer rates (0, 50,100, 150 and 200 kg ha-1) and three Tef varieties (Negus, Tesfa and local). The treatments were factorially combined and laid out in randomized complete block design with three replications. Days to 50% heading, days to 90% physiological maturity, plant height and thousand seed weight of Tef were significantly influenced by main effect of varieties, blended NPSZnB fertilizer rates and their interactions. Panicle length, dry biomass yield, lodging index, grain yield, straw yield and harvest index of Tef were significantly (P<0.001) affected by main effect of blended NPSZnB fertilizer rates and the interactions of the two factors, while the panicle length, dry biomass yield, lodging index and grain yield, straw yield and harvest index of Tef were significantly (P<0.01; 0.05) affected by main effect of varieties respectively. Highest (118.20 cm) plant height, dry biomass yield (9. 64 t ha-1), straw yield (7.02 t ha-1), grain yield (2.62 t ha-1), thousand seed weight (0.42 t ha-1) and harvest index (27.1%) were recorded from Tesfa variety with 150 kg NPSZnB ha-1 blended fertilizer rate. Similarly, the highest (7.42 t ha-1), straw yield, dry biomass yield (9.76 t ha-1), grain yield (2.34 t ha-1), thousand seed weight (0.4 g) and panicle length (44.20 cm)   were recorded from Tesfa variety with application of 200 kg NPSZnB ha-1 blended fertilizer rate and the highest total number of tillers (10.1) and effective number of tillers (9.7) were recorded with 150 kg NPSZnB ha-1 blended fertilizer rate. Grain yield of Tef showed increment by 91.22 % with the application of 150 kg NPSZnB ha-1 with Tesfa variety over the control. Highest net profit of ETB 83229.4 with marginal rate of return of 1553.71% was recorded from Tesfa variety with application of 150 kg NPSZnB ha-1 blended fertilizer rate. Therefore, farmers of the study area should use Tesfa variety based on the grain yield and net profitability benefits achieved with 150 kg NPSZnB ha-1 fertilizer rate to enhance Tef production and productivity. However, this experiment was conducted only for a single season and site, further study has to be done under different seasons and agro-ecologies to make more reliable recommendations.