Applying Siphonic Type Ebb and Flood System in Plant Factory for Producing Lettuce and Rucola
Date Issued
2016
Date
2016
Author(s)
Yu, Shu-Chi
Abstract
Plant factory using artificial light (PFAL) can precisely control aero and root-zone environment of plants, enabling the steady annual production of high quality and nutrient-rich vegetables. However, the electricity cost is nearly 25 to 30% of the operating cost. In all attempts of reducing electricity fee and consumptions, off-peak operation, selective spectra and light intensity with carbon-dioxide enrichment are common practices. Few research has focusing on the adjustment of root-zone environment. Most common culturing systems in PFAL are nutrient film technique (NFT) and deep flow technique (DFT). The purposes of this study has two folds. The first is to investigate on the feasibility of the siphonic type ebb and flood system in producing 3 cultivars of red leaf lettuce, 2 cultivars of green leaf lettuce and rucola. Use DFT system as the check. Compare not only the growth, the secondary metabolites, but also the electricity and water consumptions of two culturing systems. The study on power consumption from sowing to harvesting same fresh weight of red leaf, green leaf lettuce and rucola shown that the ratio is about 3: 1: 2. This ratio can be the guideline on pricing. Siphonic type ebb and flood system at 5/60 interval can saved 93.8% of pumping energy and saved almost 70% on nutrient solution consumption. Red leaf lettuce grows much slowly but with high anti-oxidizing capability, should have higher price. The concentration of secondary metabolites are highly influenced by the spectra of artificial light. The second purpose of this study is to investigate on the effects of the lighting spectra and intensity on the fresh weight accumulation and secondary metabolites concentration and to find the proper light source for particular cultivar of red/green lettuce and rucola. Power yield (PY, in gFW per degree of electric energy consumed) and quantum yield (QY, in gFW per mole of quanta) of all cultivars produced in this study were calculated. These quantitative measures can be very helpful in evaluating the proper light source with proper period-settings of ebb and flood system, evaluating various growth conditions, comparing with other researcher’s outcomes and compare among crops, among various culturing system. Hopefully, all these comparisons can be helpful to the emerging plant factory industry.
Subjects
Plant Factory
Ebb and Flood
Lettuce
Rucola
Secondary metabolites
Type
thesis
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