Int. J. Adv. Multidiscip. Res. (2023). 10(11): 45-59 45 International Journal of Advanced Multidisciplinary Research ISSN: 2393-8870 www.ijarm.com (A Peer Reviewed, Referred, Indexed and Open Access Journal) DOI: 10.22192/ijamr Volume 10, Issue 11 -2023 Research Article Response of Faba Bean (Vicia faba L.) to Phosphate Fertilizer Rates and Plant Population Density in the Highlands of Jimma Zone South Western Ethiopia Sisay Gurmu * , Eshetu Yadete and Muhidin Biya Jimma Agricultural Research Centre, P.O. Box 192, Jimma, Ethiopia *Corresponding author email: sis.sis1835@gmail.com Abstract Faba bean is an important pulse crop grown in the highlands (1800–3000 m.a.s.l) of Ethiopia, where the need for a chilling temperature is satisfied. However, the productivity of faba beans in Ethiopia is still far below its potential due to several constraints, such as lack of optimum plant population density and fertilizer rate. At Jimma there was no optimum recommendation of plant population density and P fertilizer rate, so the farmers and researchers uses the blanket recommendation of 250,000 plants ha -1 (40cm inter row with 10cm intra row spacing) and P fertilizer rate of 46 kg P 2 O 5 ha -1 . Hence, a field experiment was conducted to determine the optimum plant population density and P fertilizer rate for the crop production at Jimma Dedo district during the 2019 to 2021 main cropping seasons. The factorial combinations of phosphate fertilizer (23, 46, and 69 kg P 2 O 5 ha -1 ), and plant population densities of 476,190 (30*7cm), 333,333 (30*10cm), 256,410 (30*13cm), 357,143 (40*7cm), 250,000 (40*10cm), 192,308 (40*13cm), 285,714 (50*7cm), 200,000 (50*10cm), 153,846 (50*13cm) plants ha -1 were laid out in a randomized complete block design with three replications. A starter amount of nitrogen (N) fertilizer at the rate of 19 kg ha -1 was applied uniformly to all treatments per plots. Accordingly, the significant highest grain yield of 4.79 t ha -1 and highest net benefit of 135,444 Ethiopian Birr ha -1 with acceptable marginal rate of return of 671% was recorded from interaction effect of 46 kg P 2 O 5 ha -1 fertilizer rate together with 10 cm intra-row-and 50 cm inter-row spacing (200,000 plants ha - 1 ). Thus the fertilizer rate of 46 kg P 2 O 5 ha -1 and N at the rate of 19 kg ha -1 together with plant population density of 200,000 plants ha -1 (10 cm intra-row-and 50 cm inter-row spacing equivalent to 20 plants per square meter) was found to be optimum for faba bean production in South Western Ethiopia (Jimma areas) of acidic nitisols and similar agro-ecologies. Keywords Faba bean, Plant population, Phosphorus, Seed rate, and Fertilizer rate DOI: http://dx.doi.org/10.22192/ijamr.2023.10.11.004