Proof-of-concept of harvest peak control using a strawberry cultivation emulator with artificial weather chambers

Strawberry (Fragaria × ananassa) production requires a precise regulation of harvest-peak timing to meet market demand; however, fruit ripening remains sensitive to environmental fluctuations. We developed a peak-shift control system using a maturation simulator and conducted a proof-of-concept trial in climate chambers reproducing greenhouse conditions. Two control scenarios were designed: delayed flowering, wherein the predicted peaks lagged by a week and were corrected using heating offsets, and premature flowering, wherein the peaks advanced by a week and were adjusted using cooling offsets. Temperature offsets were explored within ± 5 °C, updated approximately twice weekly, to converge the predicted peaks with the target date on December 21, 2019. Results demonstrated successful alignment within ± 1 day in three of four treatments, surpassing previously reported prediction models. Cooling and heating treatments broadened and shortened harvest distributions by 2-3 and 2-4 days, respectively, suggesting the potential for balancing yield concentration. Post-harvest evaluation revealed no significant differences in morphology, grade distribution, or class proportion, although heating significantly reduced the soluble solid content, indicating a trade-off between accelerated ripening and sweetness. To our knowledge, this study provides the first experimental demonstration of simulation-in-the-loop, proactive harvest-peak control in strawberry, forming a basis for digital-twin-based cultivation control.