Yield-limiting nutrients for maize (Zea mays L.) production in Luvisols, Northwest Ethiopia

Maize ( Zea mays L.) production in Ethiopia continues to exhibit substantial yield gaps, predominantly constrained by soil fertility limitations and suboptimal fertilizer management. This study evaluated maize yield responses to macro- and micronutrient omissions, identified limiting nutrients, quantified yield gaps, and assessed soil indigenous nutrient supply (SINS) in Luvisols of Dera district, Northwest Ethiopia. The study was conducted during the 2021 growing season across eight farmers' fields using a randomized complete block design with three replications. The maize variety BH-546 was grown under ten fertilizer treatments: (1) Full nutrient (NPKSZnB) application; (2–7) individual nutrient omissions (-B, -Zn, -S, -K, -P, -N); (8) recommended NP (138 kg N + 92 kg P 2 O 5 ha −1 ); (9) recommended NP + S (30 kg S ha −1 ); and (10) Zero fertilizer (F 0 ). Application rates followed agronomic recommendations: 138 kg N, 92 kg P 2 O 5 , 60 kg K 2 O, 10.5 kg S, 5 kg Zn, and 1 kg B ha −1 . Results revealed N as the most yield-limiting nutrient, with yield responses ranging from 3260.1 kg ha −1 (site 6) to 5925.9 kg ha −1 (site 4). Phosphorus limitations were observed at 75% of sites (1239.6–3428.7 kg ha −1 response range), while K effects were site-specific (50% of sites; 772.6–3176.2 kg ha −1 response range). Maximum mean yield responses followed the order: N (4487.6 kg ha −1 ) > P (1865.5 kg ha −1 ) > K (1243.9 kg ha −1 ), with corresponding agronomic efficiencies of 32.5, 46.6, and 24.9 kg grain kg −1 nutrient applied. Secondary and micronutrients (S, Zn, B) omissions showed no significant (p>0.05) effects on yield and yield-related parameters. The mean yield gaps resulting from N, P, and K omissions were 89.0%, 36.1% and 23.1%, respectively, confirming their limiting order as N > P > K. The SINS assessments corroborated these findings, revealing severe N deficiency (11% sufficiency) compared to moderate P (63.9%) and K (76.9%) availability. These findings underscore the imperative for prioritized N management, strategic P application, and site-specific K fertilization to bridge maize yield gaps in the Northwest Ethiopia. While this single-season study provides essential baseline data, multi-year investigations are recommended to account for interannual variability and refine fertilizer recommendations.