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19 pages, 7586 KiB

Open AccessEditor’s ChoiceArticle

Predictive Modeling and Computer Vision-Based Decision Support to Optimize Resource Use in Vertical Farms

by KC Shasteen and Murat Kacira

Sustainability 2023, 15(10), 7812; https://doi.org/10.3390/su15107812 - 10 May 2023

Cited by 4 | Viewed by 1905

Abstract

This study evaluated several decision-support tools that can be used to create a control system capable of taking advantage of fluctuations in the price of resources and improving the energy use efficiency of growing crops in vertical farms. A mechanistic model was updated [...] Read more.

This study evaluated several decision-support tools that can be used to create a control system capable of taking advantage of fluctuations in the price of resources and improving the energy use efficiency of growing crops in vertical farms. A mechanistic model was updated and calibrated for use in vertical farm environments. This model was also validated under changing environmental conditions with acceptable agreement with empirical observations for the scenarios considered in this study. It was also demonstrated that lettuce plants use carbon dioxide (CO₂) more efficiently later in their development, producing around 22% more biomass during high CO₂ conditions during the fourth-week post-transplant than in the first week. A feedback mechanism using top-projected canopy area (TPCA) was evaluated for its ability to correlate with and provide remote biomass estimations. It was shown that for a given set of constant environmental conditions, a scaling factor of 0.21 g cm⁻² allowed the TPCA to serve as a rough proxy for biomass in the period prior to canopy closure. The TPCA also was able to show deviation from expected growth under changing CO₂ concentrations, justifying its use as a feedback metric. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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21 pages, 1259 KiB

Open AccessArticle

Seeds of Industry Sustainability: Consumer Attitudes towards Indoor Agriculture Benefits versus Its Advanced Technology

by Joseph Seong, Simone Valle de Souza and H. Christopher Peterson

Sustainability 2023, 15(3), 2369; https://doi.org/10.3390/su15032369 - 28 Jan 2023

Cited by 8 | Viewed by 1755

Abstract

Indoor agriculture (IA) mitigates, to some extent, global problems such as increasing demand for food and limited natural resources. Though the potential benefits of IA as a sustainable agricultural production method are widely discussed, the success of the industry depends on consumer acceptance [...] Read more.

Indoor agriculture (IA) mitigates, to some extent, global problems such as increasing demand for food and limited natural resources. Though the potential benefits of IA as a sustainable agricultural production method are widely discussed, the success of the industry depends on consumer acceptance of IA innovative technology and their willingness to consume leafy greens produced under this technology. Using cluster analysis, four distinct groups of U.S. leafy green consumers were identified: “IA Skeptics”, “IA Open”, “IA Supportive”, and “IA Engaged”. A strong positive consumer cluster emerged with no evidence of an existing cluster of consumers who could be referred as “Knowledgeable Rejectors”, often found from the studies of consumer acceptance for novel food technologies. We concluded that, overall, U.S. leafy green consumers are ready to accept IA produce, but a significant number of consumers are yet to clearly decide on their attitude towards IA technology. Based on the evidence found from this study, we identified market opportunities for the IA industry with consumers of leafy greens given their broad willingness to consume IA produce and suggest marketing strategies to expand consumer awareness and acceptance of IA produce. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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15 pages, 650 KiB

Open AccessArticle

Influence of Day and Night Temperature and Radiation Intensity on Growth, Quality, and Economics of Indoor Green Butterhead and Red Oakleaf Lettuce Production

by Sean T. Tarr, Simone Valle de Souza and Roberto G. Lopez

Sustainability 2023, 15(1), 829; https://doi.org/10.3390/su15010829 - 3 Jan 2023

Cited by 6 | Viewed by 2691

Abstract

Lettuce (Lactuca sativa) is among the most consumed vegetables worldwide and is primarily field-grown; however, indoor agriculture enables year-round, precise production. Through precise manipulation of the mean daily temperature (MDT) and photosynthetic photon flux density (PPFD), crop color, morphology, [...] Read more.

Lettuce (Lactuca sativa) is among the most consumed vegetables worldwide and is primarily field-grown; however, indoor agriculture enables year-round, precise production. Through precise manipulation of the mean daily temperature (MDT) and photosynthetic photon flux density (PPFD), crop color, morphology, and yield can be altered. Therefore, we quantified how MDT and PPFD interact and developed models predicting yield and economic viability. Eleven days after sowing, green butterhead lettuce ‘Rex’ and red oakleaf lettuce ‘Rouxaï RZ’ were transplanted into six deep-flow hydroponic tanks with day/night and MDTs of 22/15 °C (20 °C), 25/18 °C (23 °C), or 28/21 °C (26 °C), under light-emitting diodes providing a low or high PPFD of 150 or 300 µmol·m⁻²·s⁻¹ for 17-h·d⁻¹. As PPFD increased, shoot fresh mass (SFM) of ‘Rex’ increased by 29% (33.4 g). SFM of ‘Rouxaï RZ’ and shoot dry mass (SDM) of both cultivars was influenced by the interaction of MDT and PPFD. The greatest ‘Rouxaï RZ’ SFM (158.8 g) and SDM (6.42 g) were recorded at >20 °C MDT under the high PPFD; the lowest SFM (76.0 g) and SDM (3.17 g) occurred at 20 °C under the low PPFD. Similarly, ‘Rex’ SDM was greatest (7.36 g) and lowest (3.78 g) under the aforementioned MDTs and PPFDs. Increasing from the low to high PPFD increased tipburn incidence on ‘Rouxaï RZ’ from 0 to 25% and ‘Rex’ from 47 to 100%. ‘Rouxaï RZ’ had darker yellow-red foliage at lower MDTs under the high PPFD. A high MDT and low PPFD resulted in a lighter green. Finally, for the greatest SFM, while reducing energy costs as interpreted from the economic analysis, we recommend growing ‘Rex’ and ‘Rouxaï RZ’ under a PPFD of 150 and 300 µmol·m⁻²·s⁻¹, respectively, at an MDT of 23 to 26 °C depending on the cost of temperature control. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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10 pages, 2050 KiB

Open AccessArticle

Effects of Air Anions on Growth and Economic Feasibility of Lettuce: A Plant Factory Experiment Approach

by Sora Lee, Min-Jeong Song and Myung-Min Oh

Sustainability 2022, 14(22), 15468; https://doi.org/10.3390/su142215468 - 21 Nov 2022

Cited by 4 | Viewed by 2439

Abstract

Anions are molecules that have gained one or more extra electrons, and oxygen anions are the anions most commonly present in the atmosphere. Several studies have reported an improvement in plant respiration and growth through the application of air anions in several plants. [...] Read more.

Anions are molecules that have gained one or more extra electrons, and oxygen anions are the anions most commonly present in the atmosphere. Several studies have reported an improvement in plant respiration and growth through the application of air anions in several plants. In this study, the effect of air anions on the growth of lettuce was explored, and further, the economic feasibility of this technique was analyzed in a plant factory. Two cultivars of lettuce were cultivated for 4 weeks with the application of negatively ionized air in a commercial plant factory. The exposure to air anions improved the growth of the lettuce plants in the plant factory. A profitability analysis of applying air anions revealed that the annual net profit per 1500 m² cultivation area was about USD 60,000 and USD 70,000 for red leaf lettuce and Lollo bionda lettuce, respectively. Therefore, the application of air anions to lettuce in plant factories or greenhouses could increase crop production and has high economic feasibility. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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18 pages, 1157 KiB

Open AccessArticle

Red to Blue Light Ratio and Iron Nutrition Influence Growth, Metabolic Response, and Mineral Nutrients of Spinach Grown Indoors

by Viktorija Vaštakaitė-Kairienė, Aušra Brazaitytė, Jurga Miliauskienė and Erik S. Runkle

Sustainability 2022, 14(19), 12564; https://doi.org/10.3390/su141912564 - 2 Oct 2022

Cited by 8 | Viewed by 1935

Abstract

Leafy greens are increasingly being produced indoors with electric lighting from light-emitting diodes (LEDs). Red (R) and blue (B) LEDs are commonly used to ensure healthy plant growth, but biofortification techniques can potentially maximise nutritional quality. The aim of the study was to [...] Read more.

Leafy greens are increasingly being produced indoors with electric lighting from light-emitting diodes (LEDs). Red (R) and blue (B) LEDs are commonly used to ensure healthy plant growth, but biofortification techniques can potentially maximise nutritional quality. The aim of the study was to evaluate the effects of B (peak = 450 nm) and R (peak = 665 nm) light ratios (R:B) of 9:1, 3:1, and 1:3 on growth, metabolic response, and the accumulation of mineral nutrients in spinach ‘Corvair F1’ and ‘Space F1’ grown in hydroponic solutions with different iron (Fe) concentrations (2, 5, and 15 mg L⁻¹). Plant biomass and leaf length, width, and number generally decreased as the R:B decreased, leading to a high concentration of Fe in the solution. A higher Fe dose increased the contents of some other minerals but depended on the R:B and cultivar. For example, Zn generally increased with increasing Fe but Cu content decreased, especially in ‘Space F1’. There were less-profound effects of the R:B and Fe dose on metabolites or antioxidant capacity. The research findings suggest that the overall nutritional quality of spinach could improve with lighting and Fe biofortification strategies and thus increase the sustainability of indoor crop production. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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11 pages, 1010 KiB

Open AccessArticle

Adding UVA and Far-Red Light to White LED Affects Growth, Morphology, and Phytochemicals of Indoor-Grown Microgreens

by Triston Hooks, Ling Sun, Yun Kong, Joseph Masabni and Genhua Niu

Sustainability 2022, 14(14), 8552; https://doi.org/10.3390/su14148552 - 13 Jul 2022

Cited by 9 | Viewed by 2441

Abstract

White light emitting diodes (LED) have commonly been used as a sole light source for the indoor production of microgreens. However, the response of microgreens to the inclusion of ultraviolet A (UVA) and/or far-red (FR) light to white LED light remains unknown. To [...] Read more.

White light emitting diodes (LED) have commonly been used as a sole light source for the indoor production of microgreens. However, the response of microgreens to the inclusion of ultraviolet A (UVA) and/or far-red (FR) light to white LED light remains unknown. To investigate the effects of adding UVA and FR light to white LEDs on plant biomass, height, and the concentrations of phytochemicals, four species of microgreens including basil, cabbage, kale, and kohlrabi were grown under six light treatments. The first three treatments were white LED (control) and two UVA treatments (adding UVA to white LED for the whole growth period or for the last 5 days). Another three treatments consisted of adding FR to the first three treatments. The total photon flux density (TPFD) for all six light treatments was the same. The percentages of UVA and FR photons in the TPFD were 23% and 32%, respectively. Compared to white LEDs, adding UVA throughout the growth period did not affect plant height in all the species except for basil, where 9% reduction was observed regardless of the FR light. On the contrary, the addition of FR light increased plant heights by 9–18% for basil, cabbage, and kohlrabi, regardless of the UVA treatment, compared to white LED. Furthermore, regardless of UVA, adding FR to white LEDs reduced the plant biomass, total phenolic contents, and antioxidant concentrations for at least one species. There was no interaction between FR and UVA on all the above growth and quality traits for all the species. In summary, microgreens were more sensitive to the addition of FR light compared to UVA; however, the addition of FR to white LEDs may reduce yields and phytochemicals in some species. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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Review

Jump to: Research

14 pages, 462 KiB

Open AccessReview

How the Distribution of Photon Delivery Impacts Crops in Indoor Plant Environments: A Review

by Rachael Warner, Bo-Sen Wu, Sarah MacPherson and Mark Lefsrud

Sustainability 2023, 15(5), 4645; https://doi.org/10.3390/su15054645 - 6 Mar 2023

Cited by 3 | Viewed by 1973

Abstract

Indoor plant production allows for increased controllability over plant growth, particularly with the employment of specific lighting regimes. This article reviews research investigating the influence of various light regimes that provide crops with the same light spectrum and daily light integral (DLI), yet [...] Read more.

Indoor plant production allows for increased controllability over plant growth, particularly with the employment of specific lighting regimes. This article reviews research investigating the influence of various light regimes that provide crops with the same light spectrum and daily light integral (DLI), yet with different lighting schedules and intensities. The structure of these light regimes includes changing photoperiod duration and light intensity, cyclic lighting schedules (increased number of light/dark cycles over 24 h, same total illuminated time and intensity), and intermittent and fluctuating lighting (with intervals ranging from 60 s to 60 min). The most common crops investigated were leafy greens, although some fruiting, ornamental, and model crop Arabidopsis are included. Under constant DLI, extending photoperiod and reducing light intensity generally increased the total amount of biomass accumulation and increased light interception. Increases in the number of shortened light/dark cycles contributed to decreased yield, leaf area, and photosynthetic rate, compared to the more standard single light/dark cycle. Intermittent and fluctuating lighting regimes generally reduced biomass accumulation and light interception. These results indicate that the total amount of light delivered to crops is important, but how that light is delivered can influence crop growth. This review will be useful for growers and researchers when designing lighting systems and regimes to produce horticultural crops in indoor plant environment systems. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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25 pages, 2671 KiB

Open AccessReview

Principles of Nutrient and Water Management for Indoor Agriculture

by Noah James Langenfeld, Daniel Fernandez Pinto, James E. Faust, Royal Heins and Bruce Bugbee

Sustainability 2022, 14(16), 10204; https://doi.org/10.3390/su141610204 - 17 Aug 2022

Cited by 28 | Viewed by 9445

Abstract

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by transpiration [...] Read more.

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by transpiration is restored with solution that replaces the nutrients that were taken up with the water. The concentration of nutrients in this refill/irrigation solution is determined by multiplying the optimal concentration of each nutrient in plant tissue by the water-use efficiency (WUE; ratio of dry mass to water transpired). Optimal leaf nutrient concentrations are well established, but WUE in controlled environments varies widely and is less well characterized. Elevated CO₂ increases photosynthesis and demand for nutrients, but partially closes stomata and reduces transpiration; so high CO₂ dramatically increases WUE. The concentration of the refill/irrigation solution must be adjusted to account for a two-fold range of WUE, from 3 g L⁻¹ in ambient CO₂ in lower humidity, to 6 g L⁻¹ in elevated CO₂ in higher humidity. WUE and nutrient requirements vary during the vegetative and reproductive stages of growth, and adjustment of the solution over the lifecycle can be beneficial. Measurement of solution electrical conductivity (EC) is helpful, but if the solution is appropriate, low EC usually means healthy plants and active nutrient uptake. The ammonium to nitrate ratio is critical to pH management. We have applied these principles across multiple species and environments to achieve long-term, steady-state nutrient concentrations with no discharge or leaching of solution. Full article

(This article belongs to the Special Issue Sustainable Crop Production and Management: The Perspective of Controlled Environment Agriculture)

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