Effect of Seed and Blended Fertilizer (NPSB) Rates on Yield and Yield Components of Tef (Eragrostis tef /Zucc./Trotter) in Duna District, Southern Ethiopia

Low soil fertility and poor crop management practices including use inappropriate seeds rates are among the major constraints limiting the productivity of tef in Ethiopia in general and in the study area in particular. Thus, field experiment was conducted to assess the effect of rates of seed and blended fertilizer (NPSB) on growth, yield components and yield of tef and to identify economically feasible rates of seed and blended NPSB in the study area. Factorial combination of three level of tef seeding rates (3, 5 and 7 kg ha-1) and five levels of NPSB (0, 50,100, 150, 200 kg ha-1) fertilizer and 100 kg of urea (46 kg N ha-1) were used. The treatments were laid out in a Randomized Complete Block Design (RCBD) with three replications. The results revealed that the dry biomass yield were significantly (P < 0.01) affected by the main effects of NPSB fertilizer rates and panicle length affected by the effects of seed rates while, days of heading, days to 90% physiological maturity, plant height and culm length were affected by main effects of blended NPSB fertilizer and seed rate. The highest total dry biomass yield (7885 kg ha-1), panicle length (42.29 cm) were recorded at NPSB rate of 200 kg ha-1 . The maximum days of heading (63.56), days to 90% physiological maturity (103.56 days) were recorded at 0 NPSB, plant height (102.01 cm) and culm length (68.91 cm) were recorded at 200 NPSB and 150 NPSB kg ha-1, respectively. With regards to the effect of seed rate, highest total dry biomass yield (7773 kg ha-1), panicle length (42.73 cm was recorded at seed rate of 3 kg ha-1. Maximum days of heading (63.53 days), days to 90% physiological maturity (102.73 days), plant height (103.26 cm) and culm length (67.49 cm) were recorded at 3, 3, 7, and 3 kg ha-1, respectively. The interaction of the two seed and blended fertilizer (NPSB) rates also significantly affected grain yield, total tillers, productive tillers, straw yield and lodging percent. The highest grain yield (2975 kg ha-1), total tillers (21.13 m-2), productive tillers (20.13 m-2), straw yield (6192 kg ha-1) and lodging percent (74.33%) were recorded at combination of the highest rates of 200 kg NPSB fertilizer with 7 kg seed rate ha-1 while, highest grain yield were recorded at combination of 200 kg ha-1 NPSB fertilizer with 5 kg ha-1. The partial budget analysis revealed that combined applications of 200 kg blended NPSB fertilizer with seed rate of 5 kg ha-1 gave higher net benefit of 58882.85 Birr ha-1 with MRR of 1449.01%, which is above the acceptable minimum range of MRR 100%. Based on the result of this study, it can be tentatively concluded that tef at seed rate of 5 kg ha-1 and NPSB rate of 200 kg ha-1 to be appropriate for tef production in study area. However, since the experiment was conducted for one season at one location, it is suggested that the experiment has to be repeated over seasons and locations using this and other improved tef varieties in order to give a comprehensive recommendation