PHOSPHORUS USE EFFICIENCY AND PRODUCTIVITY OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES AT FEDIS AND HARAMAYA UNIVERSITY RESEARCH SITES, EAST HARARGHE ZONE, OROMIA, ETHIOPIA

Abstract

Phosphorus (P) deficiency in soils is one of the major factors limiting common bean production in Ethiopia. Common bean (Phaseolus vulgaris L.) is an important food and cash crop in East Ethiopia. Productivity of the crop is, however, low at national as well as regional levels, mainly due to low soil fertility. Phosphorus (P) deficiency is particularly important in alkaline soils of East Ethiopia affecting growth and yield of seed legumes in general and that of common bean in particular. The present study was conducted with the main objective to determine the influence of phosphorus fertilizer application on nodulation and yield of common bean varieties, and to evaluate their phosphorus use efficiency at Fedis and Haramaya University (Rare) Research Sites in East Hararghe Zone during 2022 cropping season under rain-fed conditions.The experiments were laid out in an RCBD that consisted of two factorial combinations of sixteen Common bean (Phaseolus vulgaris L.) varieties and two phosphorus rates with a total of 32 treatments. A total of 16 common bean varieties which are widely grown in Ethiopia were used for the experiment; namely, Awash-melka, Awash 1, Awash 2, Ayenew, Babile, Batu, Chercher, Dursitu, Fedis, Gonfa, Haramaya, Hirna, Hundane, Kunfazek, Nasir and Xinfi varieties and two levels of phosphorus fertilizer (0 kg P ha-1 and 30 kg P ha-1) were used for the treatment combinations. Triple super- phosphate was used as P source. Composite soil sample was taken for determination of selected soil physio-chemical properties before planting. At early flower-setting, during maturity stages and after harvesting, plant samples were collected and analyzed for their shoot P content, shoot biomass, nodulation and yield components. Moreover, grain yield P content and straw P content were analyzed to estimate P use efficiency of varieties. Results indicated that nodule number, nodule dry weight and shoot dry weight parameters were significantly (p <0.05) affected by the interaction effect of varieties and P rates at low soil P-level at Fedis site.The highest nodule number per plant (98.66) and highest nodule dry weight per plant (0.46 g) were obtained from a treatment combination of Xinfi variety and 30 kg P ha-1); and the highest shoot dry weight (38.56 g) was produced from a treatment combination of Fedis variety with 30 kg P ha-1 at Fedis experimental site. The highest hundred seeds weight (52.5 g), grain phosphorus (37.23 kg P ha-1) and grain yield (3596 kg ha-1), were produced from a treatment combination of Ayenew variety and 30 kg P ha-1; and the highest total pods per plant(27.4), highest straw phosphorus (26.66) and highest biological yield (5833.4 kg P ha-1) were obtained from the treatment combinations of Chercher, Awash 2 and Xinfi varieties by 30 kg P/ha; whereas the highest seed number per plant was yielded by a treatment combination of Hundane variety (5.93) and 0 kg P ha-1by medium soil P-level at Haramaya experimental site. The highest grain yield value (3596.6 kg/ha) was produced by Ayenew variety; whereas the lowest value (1156.4 kg/ha) was obtained from Batu variety with the P application of 30 kg/ha. The highest grain phosphorus content (37.23 kg P/ha) was also obtained from Ayenew variety and the lowest (7.46 kg P/ha) from Batu variety with P application of 30 kg P/ha. Generally, the application of fertilizer have provided valuable results regarding grain yield and grain P-content only in a single common bean variety known as Ayenew at Rare site