Title : Effect of mineral nitrogen, phosphorus, and potassium fertilizers on the productivity of faba bean (Vicia faba L.) in acidic soils of wolaita zone, southern ethiopia
Nutrient depletion along with soil acidity are among the major factors that limit faba bean production in Ethiopia. Therefore, afield experiment was conducted in the Kokate Marachare sub-district of Sodo Zuria district in Wolaita Zone during the 2019 and 2020 cropping seasons, to determine the response of faba bean to different rates of nitrogen (N), phosphorus (P), and potassium (K) fertilizers under lime treated soil conditions. The treatments consisted of three rates of nitrogen fertilizer (0, 23, and 46 kg N ha–1), three rates of phosphorus fertilizer (0, 46, and 92 kg P2O5 ha–1), and three rates of potassium fertilizer (0, 30, and 60 kg K2O ha–1). A faba bean variety named Tumsa was used as the test crop. The experiment was laid out as a randomized complete block design (RCBD) and replicated three times per treatment. Data were collected on growth, yield components, yield and nutrient use efficiency. The data were subjected to analysis of variance. The results indicated that nitrogen, phosphorus, and potassium interacted to influence plant height, number of branches per plant, and stem girth. The interaction of 23 kg N × 92 kg P2O5× 60 kg K2O ha–1 increased plant height, number of branches per plant, and stem girth of the faba bean plant by about 18%, 62.6%, and 55.6%, respectively, over the control treatment. Similarly, significantly highest average above-ground dry biomass yield (11.8 t ha–1), number of pods per plant (17), number of seeds per pod (4), stover yield (6.83 t ha–1), hundred seed weight (88 g), and seed yield were obtained from the interaction of 23 kg N × 92 kg P2O5× 60 kg K2O ha–1. The average seed yield of the crop obtained in response to the application of 23 kg N × 92 kg P2O5× 60 kg K2O ha–1 exceeded the average seed yield obtained from the control plot by about 360%. However, the highest mean net benefit (163,067.5 ETB ha–1) with an acceptable marginal rate of return of 3,987% was obtained from the N, P, and K fertilizers combination at 23 kg N-46 kg P2O5-30 kg K2O ha–1, respectively. Thus, N, P, and K fertilizers combination at 23 kg N-46 kg P2O5-30 kg K2O ha–1are suggested for faba bean production in the acidic soils of the Woliata Zone.