以單晶片調控植物工廠內養液及光質

Abstract

本研究旨在以單晶片建立一套適用於植物工廠的養液與光質調控系統，並驗證其適用性。養液調控以導電度與酸鹼度感測器為感知元件，透過功率調節電路控制蠕動泵浦轉速進行流量調控以調整營養液濃度與酸鹼度。光質調控則是透過脈衝訊號調節驅動電路的輸出電流，達成LED燈板R、G、B三色各255 階的調變功能。各項感測資訊透過微控制器及藍牙模組與 APP 人機介面進行無線數據傳輸，具備即時監控與參數調整功能。 本研究同時探討四種光質對四種葉菜類作物育苗與育成期生長之影響，四種光質分別為冷白 LED (R25:G49:B26)、紅藍 LED (R87.5:G0:B12.5)、紅白 LED (R73.5:G16:B10.5) 及紅藍白 LED (R81.9:G6.4:B11.7)。結果顯示紅藍白 LED 適合用於小菘菜和京水菜之栽培，紅白LED適合皺葉萵苣之栽培。羽衣甘藍較為特殊，幼苗期使用紅藍白 LED，育成期使用紅白 LED 為最佳。本研究亦探討所開發的養液調控系統針對不同作物的調控方式，首先探討使用所開發的自動調控系統 (即時調控) 與傳統的手動調控方式 (一週一次) 對小菘菜和京水菜生長之影響；其次探討如何使用所開發的系統用於降低小菘菜的硝酸鹽濃度。結果顯示栽培期間養液導電度和酸鹼度有較大幅度的變動不利於作物生長，自動調控系統 (即時調控) 在地上部鮮重的表現上可高出 34 ~54 %。採收前需調整養液濃度的設定，小菘菜的硝酸鹽濃度可有效降低，但仍偏高，顯示此調整模式的不足，後續可增加搭配光質 (提高紅光比例) 或提高光量或光期 (日累積光量) 的調整，硝酸鹽濃度應可進一步再降低。 本研究建置的系統允許在栽培期間不需更換燈具就可依照設定的光配方調整光質，亦可全程提供穩定的營養液條件，提供作物於最佳的地上部光環境與最佳的地下部養液環境內成長。系統建置成本遠低於使用 PC 或 PLC 的系統，應該更有推廣的價值。

This study aims to develop a nutrient solution and light quality control system for crop production in plant factory by microcontroller and verify the suitability of the system. The nutrient solution system uses an electrical conductivity sensor and pH sensor as a sensing element; through power adjustment circuit to regulate the peristaltic pump flow rate to adjust the electrical conductivity and pH of the nutrient solution. Light control regulates the output current of the drive circuit through pulse width signal to control light panel RGB 0-255 stages of brightness. All sensors wireless transmits data via microcontroller and Bluetooth to Android application provides a real-time monitoring system. In this study, we first investigate the effects of different light quality treatments on four leafy vegetable crops growth. Experiment uses four different light quality: Cool White LED (R25:G49:B26), Red-Blue LED (R87.5:G0:B12.5), Red-White LED (R73.5:G16:B10.5) and Red-Blue-White LED (R81.9:G6.4:B11.7). The results showed that Komatsuna (Brassica rapa var. perviridis) and Mizuna (Brassica rapa var. laciniifolia) planted by RBW LED, Curled Lettuce (Lactuca sativa L. var. crispa) planted by RW LED has the best growth performance. Kale (Brassica oleracea var. sabellica) cultivation is more special, the seedling stage uses RBW LED , final growh stage uses RW LED has the best growth result. In addition, we investigate the regulation of nutrient solution system control methods for different crops. First of all, to explore the impact of the use of the developed automatic adjustment system (real-time adjustment) and traditional manual control (adjust once a week) on the growth of Komatsuna and Mizuna. Second, explore how to use the nutrient solution control system developed to reduce the nitrate concentration of Komatsuna. The results show plants grown slowly under traditional manual control and the big fluctuation of EC and pH values should be the reason. The automatic control nutrient solution treatment fresh weight was 34~54 % higher than manual control treatment. Before harvesting, the setting of the concentration of nutrient solution should be calibrate, and the nitrate concentration of the Komatsuna can be effectively reduced, but still high. The results show that the deficiency of this adjustment mode, by increasing the combination of light quality (increasing the red light ratio) or the adjustment of the light intensity or the photoperiod (Daily Light Integral) can be reduced. The system developed in this study allows the light quality to be adjusted according to the light recipe without changing the light source during cultivation, and can also provide stable nutrient solution conditions throughout the process, providing the best above-ground light environment and the best underground nutrient solution environment for plant. System construction costs are much lower than those using a PC or PLC system and should be more valuable.