Soybean is one of the forage legumes it can be planted for high-protein feed, such as grazing, haying, or ensiling. The objective of the experiment was to evaluate the effects of fertilizer level and row spacing on soybean (Glycine max (L.) Merrill) agronomic performance, forage yield, and nutritive value under irrigation conditions. The field study was conducted in a factorial arrangement of randomized complete block design (RCBD) using two factors (three-row spacing and four fertilizer levels) with three replications .The row spacing 50, 60, and 70 cm were combined with 0, 100, 120, and 140 kg ha NPS fertilizer rates. Blended NPS (Nitrogen, phosphorus and sulfur) fertilizer was applied at the time of planting for all treatments. The agronomic characteristics and forage yield data were collected at 50% flowering stage, weighed (for yield estimation), dried, and then ground subsamples taken for analysis of crude protein (CP), crude protein yield (CPY), ash, dry matter, organic matter, dry organic matter digestibility (DOMD), fiber contents, in vitro dry matter digestibility (IVDMD) and metabolizable energy (ME). The collected data were subjected to a general linear model for statistical analysis system (SAS) version 9.0. The result indicated that there was significant interaction (P < 0.05) effect in the fertilizer level and spacing only in the number of nodules, but for nutritional value of forage soybean DM, CP, CPY, and ME. had an interaction effect. Both spacing and NPS fertilizer application showed significant differences (P < 0.001) in the majority of agronomic characteristics like -1plant height, number of branch, number of leaf per plant, number of nodule, dry matter yield, and leaf to steam ratio. The agronomic parameters and nutritional quality had better performance in 140 kg ha -1 NPS application and 70 cm row spacing than in lower fertilizer levels. However, the dry matter yield and crude protein yield were better on narrow (50 cm) spacing. Overall, significantly (P < 0.001) maximum dry matter yield (12.2 t ha ) was recorded from 50 cm row spacing, while the lowest dry matter yield (8.4 t ha ) was from 70 cm row spacing. Regarding fertilizer levels, maximum dry matter yield was recorded from high-level NPS fertilizer application (10.9 t ha -1 ) while the lowest (8.7 t ha ) was recorded from no NPS fertilizer application. The highest CP content (17.33%) was recorded from 140 kg NPS fertilizer application while the lowest (13.24%) was from no NPS fertilizer application. The highest CP content was recorded from 70 cm row spacing (16%) while the lowest CP (14.7%) was recorded from 50 cm row spacing. The highest net benefit (40212 birr) and the highest marginal rate of return (859.85%) from 140 and 100 kg NPS fertilizer applications with 50 cm row spacing, respectively. Therefore, forage soybean with 100 kg ha 1 NPS fertilizer rate and 50 cm row spacing are given priority in terms of marginal rate of return and are recommended for wider utilization under smallholder farmers' conditions in the farming system with similar agro-ecologies using irrigation season. Animal evaluation feed trial should be implemented to know the effect of the feeding value of forage soybean [Glycine max (L) Merrill]. -1 -1 -1 -