Effect of Nitrogen Rate and Irrigation Regime on Tomato (Solanum lycopersicum L.) Yield in the low lands of North Shoa, Amhara Region, Ethiopia

Crop productivity can be increased by application of optimum water and fertilizer. A field experiment was conducted in Eferatagidm district, North Shewa, Amhara, Ethiopia, during the irrigation season of 2019 and 2020 with the objective of determining N rate and irrigation depth for optimum tomato yield. The experiment consisted of factorial combinations of three-irrigation depths (75% ETc, 100% ETc, and 125% ETc) and four N rates (0 kg N ha − 1 , 46 kg N ha − 1 , 92 kg N ha − 1, and 138 kg N ha − 1 ). The treatments were laid out in a split-plot design with four replications. The main plot was arranged for the irrigation regime while the subplot was for the nitrogen rates. Data on growth, yield, and yield-related traits of tomatoes include; plant height, number of fruit clusters per plant, fruit length, fruit diameter, number of marketable fruits, number of un-marketable fruits, the total number of fruits, marketable fruit yield, un-marketable fruit yield, total yield were collected. Data were subjected to analysis of variance using R studio. The results indicated that the experimental site had low total nitrogen content and application of N fertilizer significantly improved tomato yield. Increasing irrigation depth also significantly increased tomato yield. The result indicated that the highest mean marketable fruit yield (35903 kg ha − 1 ) was obtained from the combined application of 125% ETc with 92 kg N ha − 1 while the lowest (13655 kg ha − 1 ) marketable fruit yield was obtained from 75% ETc with 92 kg N ha − 1 . The partial budget analysis also indicated that the highest net benefit (266272 ETB ha − 1 ) as well as acceptable marginal rate of return (1240) for the invested capital was recorded from the combined application of 125% ETc with 92 kg N ha − 1 . Therefore, the application of 125% ETc with 92 kg N ha − 1 resulted in highest net benefit.