Watermelon is a significant Cucurbitaceae crop that is widely cultivated around the world. However, production and productivity of the crop in Ethiopia are very low compared to the global average of 32.6 t ha −1 , which is mostly associated with soil fertility depletions as a result of inappropriate application of fertilizer. Therefore, this field experiment was conducted to enhance the production and productivity of watermelon by identifying economically optimum rates of Eco‐Green and blended (NPSB) fertilizer in West Dembia district, Northwest Ethiopia. The experiment was designed in factorial combinations of four levels of Eco‐Green (0, 75, 150, and 225 L ha −1 ) and four levels of blended NPSB fertilizer (0, 125, 250, and 375 kg NPSB ha −1 ), which were laid down in a randomized complete block design (RCBD) with three replications. The results of the study revealed that Eco‐Green and blended NPSB fertilizers had significant effect on growth, fruit yield and quality attributes of watermelon. Furthermore, the combined effect of Eco‐Green and blended NPSB fertilizers had a significant ( p < 0.001) influence on number of total fruit per plant, marketable fruit yield, total fruit yield, pulp weight, and total soluble solids. The highest marketable (59 t ha −1 ) and total fruit yield (83 t ha −1 ) were recorded from the treatment combinations of 150 L Eco‐Green ha −1 and 250 kg NPSB ha −1 fertilizer rates with net benefit of (1,228,825 ETB ha −1 ) and acceptable marginal rate of return of (27552.8%). Therefore, the combined application of this rate was recommended for economical and sustainable watermelon production in the study area and similar agroecology. However, this result is one season and location data and needs to be confirmed across locations and over seasons for broader applicability.
Amare et al. (Thu,) studied this question.