Enhancing high-tunnel tomato productivity through nitrogen and phosphorus optimization in western Amhara, Ethiopia

Abstract Background : High-tunnel tomato production technology has emerged as a vital technology in western Amhara, Ethiopia, to address the production challenges during the rainy season. However, its productivity is low, mainly because of the absence of recommended rates of N and P nutrients. Therefore, two-year experiments were conducted in the 2023 and 2024 main seasons to optimize N and P nutrients. Methods : The experiment involved four levels of nitrogen (0, 160, 320, and 480 kg N ha −1 ) and four levels of phosphorus (0, 40, 80, and 120 kg P 2 O 5 ha −1 ), arranged in a factorial RCBD with three replications. Phenology, growth, yield, and quality data were collected and analyzed using R software V.4.0. Results : The results revealed that the combined application of N and P fertilizers significantly ( P < 0.01) affected the productivity of tomato. The combined application of 320/120 kg ha −1 N/P 2 O 5 was the optimal combination for flower number cluster −1 (7.71), fruit number cluster −1 (6.27), fruit set percentage (81.15%), marketable yield (88.21 tons ha −1 ), total yield (90.71 tons ha −1 ), fruit firmness (13.01 N), and total soluble solids (4.37 °Brix). Conversely, the lowest performance was observed in the untreated plots and plots treated with either of the two nutrients. The regression analysis found that the combination rate can be extended up to 358/128 kg ha −1 N/P 2 O 5 for maximum yield. Conclusion : This combination greatly enhanced tomato productivity and provided the highest net benefit of 3,506,745.00 ETB ha −1 with a marginal rate of return of 2370.5%, which is recommended for high-tunnel tomato production in the study area.