控制環境內波士頓萵苣立體化栽培之研究

Abstract

本研究旨在探討於環控室內以人工光源立體化栽培波士頓萵苣 (Lactuca sativa) 的各項操作條件，環控室內部主要包含空調設備、自製栽培床架、循環養液供應系統、監控系統、人工光源及二氧化碳施肥系統等。環控室面積為5 m2，可擺放三個栽培床架，明/暗期溫度控制在25 / 20 ℃，二氧化碳濃度控制在1200 ppm。 如採批次量產方式，經過7 天育苗與28天的育成，於四層的栽培架中採用循環方式且每日循環養液12 次，每次15 分鐘，在栽培期終了每一栽培架可收穫76株平均鮮重為120.1 ± 19.6 g的萵苣。將環控室放大十四倍可每日穩態量產 152株平均重量為120 g 的萵苣，單位面積年產能相當於95 kg/m2/year，遠高於美國康乃爾大學的配備人工光源的750 m2精密溫室水耕栽培萵苣的69 kg/m2/year年產能。 本研究初步證實於環控室內完全不使用農藥，以人工光源立體化量產低硝酸鹽的波士頓萵苣在技術上為可行。透過成本分析初步也瞭解本系統在未包括人工費用與廠房及設備的折舊之下的栽培成本為12.58元/100 g。這更說明了只要在廠房與設備成本上做合理控管，本系統在財務上也是相當吸引人的。

The focus of this study is to investigate on various operating conditions in a controlled environment using tubular florescent lamp as the light source to grow Boston lettuce (Lactuca sativa) in multi-layer benches. The controlled chamber equipped with air conditioning system, benching system, re-circulating nutrient system, monitoring and control system, artificial lighting system and carbon dioxide enrichment system. Area of the air-tight chamber is 5 square meters and is suitable for 3 benches each with 4 layers. The light / dark temperature is controlled at 25 / 20 degree C and the carbon dioxide is controlled at 1200 ppm. It takes 35 days to grow Boston lettuce from seeding to harvesting. Seedling stage is 7 days and the rest 28 days is the production stage. Only the production stage is conducted in the growth chamber. In the multi-layer bench, When the nutrient is re-circulating 12 times per day, 15 minutes per each time, totally 76 heads of lettuce can be harvest with the fresh weight of 120.1 ± 19.6 g/head. Estimated annual production per square meter of our system is 95 kg, which is much higher than 69 kg, which is unit area annual production of the 750 m2 Cornell’s hydroponic greenhouse equipped with artificial light. This study proof that growing Boston lettuce with low nitrate content without using pesticide and totally relied on artificial light in a multi-layer benching system is possible. Through cost analysis, we also derived that the production cost of the Boston lettuce is 12.58 NT dollars per 100 g without considering labor cost and depreciation of structure and equipment. Thus making the system not only technological viable but also economically abstractive. This is the first step of the plant factory research and there is still a long way to go.