Abstract
There are many issues that will make producing sufficient food for the growing global population a difficult task. Controlled Environment Agriculture (CEA), integrating environmental control and hydroponic technology, can efficiently produce more food with less inputs. The new production practices of vertical farms have precision environmental control and subsequently more consistent and higher productivity with the advantage of being located almost anywhere, especially closer to population centers. A vertical Farm can be described as a fully indoor production system that uses electrical lamps for photosynthetic lighting and high density crops grown in multiple layers. CEA technology of supplementing atmospheric carbon dioxide (CO2) in greenhouse applications to compensate for low light levels, maintain plant photosynthesis, and enhance profits is practiced. However, due to the amount of ventilation generally required in greenhouse environments, maintaining CO2 concentrations can be expensive and impractical. The closed configuration of vertical farms can enhance CO2 use efficiency, however, the use of electrical lighting results in a large electrical power requirement. The goal of this study was to evaluate the level of daily light integrals (DLI) and atmospheric CO2 concentrations that would provide savings of electrical power usage and CO2 supplementation while producing a marketable head lettuce (Butterhead, cv. Fairly) product. Experiments were conducted in a 45 m2 environmentally controlled (air temperature, PPF, DLI, CO2, DO, EC and pH) vertical farm research facility with six values of DLI (9, 11, 13, 15, 17, 19 mol m-2 d-1) and six CO2 concentrations (400, 550, 700, 850, 1000, 1300 ppm), which were maintained constant from transplant through harvest. Plant shoot fresh and dry weights were measured at harvest and compared with resource use accounting of electrical energy for LED lighting, heat pumps for air conditioning, water pumps for nutrient solution circulation, and air pump to maintain dissolved oxygen in the nutrient solution for the roots. It was demonstrated that 1) a linear relationship of increase biomass to increase of DLI existed for all treatments; 2) plants within the 850 ppm CO2 concentration yielded the largest average fresh and dry shoot weights and yields decreased as CO2 was further elevated; 3) the physiological disorder tip burn was more pervasive and appeared sooner for either larger CO2 concentrations and larger DLIs. No tip burn was observed at 400 and 550 ppm CO2 concentrations within any DLI; 4) lettuce grown in lower light intensities had larger physical size dimensions, but were less dense and had less biomass, compared to lettuce grown in higher light intensities which had a smaller physical dimension, but were more dense and thus greater biomass; 5) the metrics for the average overall resource use efficiencies of plant production for fresh weight edible biomass were 69 gfresh kWh-1, 147 gfresh LCO2-1, 20.7 LH2O kgfresh-1 y-1 , and 86.0 kgfresh m-2 y-1; 6) the potential electrical savings from changing the DLI (mol m-2 d-1)/CO2 (ppm) combination from 17/400 to 13/850 in the small scale research facility, to which this study was conducted, is $59 per harvest and $762 for the year (14.4% savings). Larger commercial vertical farm operations lowering the DLI and increasing CO2 concentrations could have a much greater electrical savings potential.
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Claims 17
Claim · model-written summary
Biomass rose linearly with DLI across treatments.
- Taxon
- Lettuce
Lactuca sativat0 - Treatment
- DLIe0
- Outcome
- biomasse0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a linear relationship of increase biomass to increase of DLI existed for all treatments”
t0“Lettuce”
Claim · model-written summary
At 850 ppm CO2, fresh and dry shoot weights were largest.
- Taxon
- LettuceLactuca sativat0
- Treatment
- 850 ppm CO2 concentratione0
- Outcome
- fresh and dry shoot weightse0
- Direction
- largeste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants within the 850 ppm CO2 concentration yielded the largest average fresh and dry shoot weights and yields decreased as CO2 was further elevated”
t0“Lettuce”
Claim · model-written summary
Yield declined with CO2 above 850 ppm.
- Taxon
- LettuceLactuca sativat0
- Treatment
- CO2 was further elevatede0
- Outcome
- yieldse0
- Direction
- decreasede0
- Comparator
- 850 ppm CO2 concentratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants within the 850 ppm CO2 concentration yielded the largest average fresh and dry shoot weights and yields decreased as CO2 was further elevated”
t0“Lettuce”
Claim · model-written summary
Tip burn was more pervasive and earlier with larger CO2 concentrations.
- Taxon
- LettuceLactuca sativat0
- Treatment
- larger CO2 concentrationse0
- Outcome
- tip burne0
- Direction
- more pervasivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the physiological disorder tip burn was more pervasive and appeared sooner for either larger CO2 concentrations and larger DLIs”
t0“Lettuce”
Claim · model-written summary
Tip burn was more pervasive and earlier with larger DLIs.
- Taxon
- LettuceLactuca sativat0
- Treatment
- larger DLIse0
- Outcome
- tip burne0
- Direction
- more pervasivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the physiological disorder tip burn was more pervasive and appeared sooner for either larger CO2 concentrations and larger DLIs”
t0“Lettuce”
Claim · model-written summary
No tip burn occurred at 400 or 550 ppm CO2 at any DLI.
- Taxon
- LettuceLactuca sativat0
- Treatment
- 400 and 550 ppm CO2 concentrationse0
- Outcome
- No tip burne0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No tip burn was observed at 400 and 550 ppm CO2 concentrations within any DLI”
t0“Lettuce”
Claim · model-written summary
Lower light produced larger physical size dimensions.
- Taxon
- lettuceLactuca sativae0
- Treatment
- lower light intensitiese0
- Outcome
- physical size dimensionse0
- Direction
- largere0
- Comparator
- higher light intensitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce grown in lower light intensities had larger physical size dimensions, but were less dense and had less biomass, compared to lettuce grown in higher light intensities which had a smaller physical dimension, but were more dense and thus greater biomass”
t0“Lettuce”
Claim · model-written summary
Lower light produced less dense.
- Taxon
- lettuceLactuca sativae0
- Treatment
- lower light intensitiese0
- Outcome
- densee0
- Direction
- lesse0
- Comparator
- higher light intensitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce grown in lower light intensities had larger physical size dimensions, but were less dense and had less biomass, compared to lettuce grown in higher light intensities which had a smaller physical dimension, but were more dense and thus greater biomass”
t0“Lettuce”
Claim · model-written summary
Lower light produced less biomass.
- Taxon
- lettuceLactuca sativae0
- Treatment
- lower light intensitiese0
- Outcome
- biomasse0
- Direction
- lesse0
- Comparator
- higher light intensitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce grown in lower light intensities had larger physical size dimensions, but were less dense and had less biomass, compared to lettuce grown in higher light intensities which had a smaller physical dimension, but were more dense and thus greater biomass”
t0“Lettuce”
Claim · model-written summary
A production resource metric was 69 gfresh kWh-1.
- Taxon
- LettuceLactuca sativat0
- Outcome
- resource use efficienciese0
- Value
- 69 gfresh kWh-1e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the metrics for the average overall resource use efficiencies of plant production for fresh weight edible biomass were 69 gfresh kWh-1, 147 gfresh LCO2-1, 20.7 LH2O kgfresh-1 y-1 , and 86.0 kgfresh m-2 y-1”
t0“Lettuce”
Claim · model-written summary
A production resource metric was 147 gfresh LCO2-1.
- Taxon
- LettuceLactuca sativat0
- Outcome
- resource use efficienciese0
- Value
- 147 gfresh LCO2-1e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the metrics for the average overall resource use efficiencies of plant production for fresh weight edible biomass were 69 gfresh kWh-1, 147 gfresh LCO2-1, 20.7 LH2O kgfresh-1 y-1 , and 86.0 kgfresh m-2 y-1”
t0“Lettuce”
Claim · model-written summary
A production resource metric was 20.7 LH2O kgfresh-1 y-1.
- Taxon
- LettuceLactuca sativat0
- Outcome
- resource use efficienciese0
- Value
- 20.7 LH2O kgfresh-1 y-1e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the metrics for the average overall resource use efficiencies of plant production for fresh weight edible biomass were 69 gfresh kWh-1, 147 gfresh LCO2-1, 20.7 LH2O kgfresh-1 y-1 , and 86.0 kgfresh m-2 y-1”
t0“Lettuce”
Claim · model-written summary
A production resource metric was 86.0 kgfresh m-2 y-1.
- Taxon
- LettuceLactuca sativat0
- Outcome
- resource use efficienciese0
- Value
- 86.0 kgfresh m-2 y-1e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the metrics for the average overall resource use efficiencies of plant production for fresh weight edible biomass were 69 gfresh kWh-1, 147 gfresh LCO2-1, 20.7 LH2O kgfresh-1 y-1 , and 86.0 kgfresh m-2 y-1”
t0“Lettuce”
Claim · model-written summary
Changing DLI/CO2 from 17/400 to 13/850 could save $59 per harvest.
- Taxon
- LettuceLactuca sativat0
- Treatment
- 13/850e0
- Outcome
- potential electrical savingse0
- Direction
- savingse0
- Value
- $59 per harveste0
- Comparator
- 17/400e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the potential electrical savings from changing the DLI (mol m-2 d-1)/CO2 (ppm) combination from 17/400 to 13/850 in the small scale research facility, to which this study was conducted, is $59 per harvest and $762 for the year (14.4% savings)”
t0“Lettuce”
Claim · model-written summary
Changing DLI/CO2 from 17/400 to 13/850 could save $762 for the year.
- Taxon
- LettuceLactuca sativat0
- Treatment
- 13/850e0
- Outcome
- potential electrical savingse0
- Direction
- savingse0
- Value
- $762 for the yeare0
- Comparator
- 17/400e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the potential electrical savings from changing the DLI (mol m-2 d-1)/CO2 (ppm) combination from 17/400 to 13/850 in the small scale research facility, to which this study was conducted, is $59 per harvest and $762 for the year (14.4% savings)”
t0“Lettuce”
Claim · model-written summary
Changing DLI/CO2 from 17/400 to 13/850 could save 14.4% savings.
- Taxon
- LettuceLactuca sativat0
- Treatment
- 13/850e0
- Outcome
- potential electrical savingse0
- Direction
- savingse0
- Value
- 14.4% savingse0
- Comparator
- 17/400e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the potential electrical savings from changing the DLI (mol m-2 d-1)/CO2 (ppm) combination from 17/400 to 13/850 in the small scale research facility, to which this study was conducted, is $59 per harvest and $762 for the year (14.4% savings)”
t0“Lettuce”
Claim · model-written summary
Larger vertical farms could gain greater electrical savings by lowering DLI and raising CO2.
- Taxon
- LettuceLactuca sativat0
- Treatment
- lowering the DLI and increasing CO2 concentrationse0
- Outcome
- electrical savings potentiale0
- Direction
- greatere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Larger commercial vertical farm operations lowering the DLI and increasing CO2 concentrations could have a much greater electrical savings potential”
t0“Lettuce”
The same questions in other papers
co2 · yield · Lactuca sativa (garden lettuce)Results differ
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- positive
- positive
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242 papers in the same direction as this paper · 54 in the opposite direction · 3 reporting no difference from an alternative
- positive
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See all 300 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.