Abstract:
Haramaya University main campus, Eastern Ethiopia, with the objectives of evaluating the effect of methods of Rhizobium inoculation and phosphorus (P) rates on nodulation, yield components and yield of faba bean and to identify economically beneficial treatment (s) for higher yield of faba bean. Factorial combinations of five P levels (0, 23, 46, 69, 92 kg P2O5 ha-1) and four levels of Rhizobium inoculation methods (uninoculated, seed inoculated, soil inoculated, seed + soil inoculated) were laid out in a Randomized Complete Block Design with three replications. Interaction of Rhizobium inoculation method (RIM) and P rates significantly (P<0.05) affected number of pod per plant and grain yield. Except percent of effective nodules, plant height and days to 50% flowering all parameters were significantly (P<0.05) affected by P rates. Similarly, except hundred seed weight and harvest index, significant effect was observed due to RIM. Among the different rates of P, 46 kg P2O5 ha-1 resulted in the highest nodule dry weight (313.7 mg), nodule volume (1.98 ml), number of primary branches (2.63), number of seeds pod-1 (2.56), hundred seed weight (89.59 g) and above ground dry biomass (9648 kg ha-1). However the highest number of nodules (116.2), and harvest index (0.37) were recorded from 23 kg P2O5 ha-1. Seed + soil inoculation method resulted in the highest number of nodules (120.7), percent of effective nodules (88.67%), nodule dry weight (312.8 mg), nodule volume (1.84 ml), number of primary branches (2.19), plant height (146.2 cm), number of seeds pod-1 (2.52), hundred seed weight (85.10 g) and above ground dry biomass (9646 kg ha-1). Applying 46 kg P2O5 ha-1in combination with seed +soil inoculation increased number of pod plant-1 and grain yield by 67.9% and 63.8% over the control treatment respectively. The highest grain yield (4222 kg ha-1) with the highest net benefit of 55037 ETB ha-1 was obtained from the combined application of Rhizobium inoculation on seed + soil and application of 46 kg P2O5 ha-1which was found to be superior in increasing yield of faba bean production at Haramaya.
