Melon (Cucumis melo L.) is one of the important fruits cultivated in Taiwan. Proper water management significantly impacts both the production and quality of melons. During the period of 2022- 2023, this project developed a model for evaluating the water status of melon ’Jia-Yu’, crop coefficients for each growth stage, water use coefficients for key production areas, crop coefficients of Penman–Monteith equation in soil cultivation, and timing for seedling water supply. This year, field verification of these models was carried out. The water status evaluation model was used to assist in determining irrigation timing, while crop coefficients were applied using the reference evapotranspiration-crop coefficient procedure (ET₀-Kc procedure) to estimate the crop's water requirements. The results showed that applying the ET₀-Kc procedure in combination with post-fruit reduction irrigation could reduce water usage in seedling farms by approximately 19.3% for spring crops and 25.7% for summer-autumn crops without compromising fruit quality (including fruit weight, length, width, flesh thickness, sweetness, and cracking rate). On the other hand, applying the melon water status evaluation model to seedling farm cultivation conditions showed that the model's negative predictive value and accuracy were at an acceptable to good level, though the positive predictive value was somewhat low. Future modifications to the model could improve the balance between predicting positive (water shortage) and negative (normal) conditions. Regarding soil irrigation water use information, during the high temperature summer cultivation period, reducing irrigation resulted in a significant decrease in yield. However, reducing irrigation by 20% in autumn cultivation increased sugar content, and reducing water supply by 40% could improve the good fruit rate to 71%. This suggests that appropriate water-saving strategies should be considered for autumn production.

▲Fig.1. ET0-Kc procedure off-site verification results in 2024.

▲Fig.2. Field validation water status evaluation model performance in 2024.

▲Fig.3. Estimated water consumption per hectare for melon cultivation during the entire growth period in 2014. (green dots: water consumption for conventional cultivation; red dots: 20% reduction in water consumption; blue dots: 40% reduction in water consumption)

▲Fig.4. The melon fruit characteristics of the first crop.

▲Fig.5. The melon fruit characteristics of the second crop.