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Kellie J. Walters, Bridget K. Behe, Christopher J. Currey and Roberto G. Lopez

, N.C. Raudales, R.E. Brumfield, R.G. Laury-Shaw, A. Wilke, A.K. Lopez, R.G. Burnett, S.E. 2019 Controlled environment food production for urban agriculture HortScience 54 1448 1458 Gordon, R. 2016 State of the vegetable industry survey shows growers

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Marc W. van Iersel, Geoffrey Weaver, Michael T. Martin, Rhuanito S. Ferrarezi, Erico Mattos and Mark Haidekker

Controlled environment agriculture, including greenhouses and indoor production facilities, is becoming an increasingly important part of the global food system. Totally enclosed, indoor vegetable growing facilities were developed in Japan beginning

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Manette Schönfeld and Cary A. Mitchell


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Thomas S.C. Li, K.E. Bedford and P.L. Sholberg

Traditionally, American ginseng (Panax quinquefolium L.) seeds are stratified for 18 to 22 months, before seeding, in a sandbox buried outdoors in late August or early September. Uncontrolled fluctuating temperature and moisture levels and the presence of pathogenic organisms in the seed box can cause seeds to sprout prematurely, rot, dry out and die. A study was initiated to shorten the lengthy stratification period, and to increase seed viability and percentage of germination by stratifying seeds indoors under a controlled environment. Seeds were subjected to various periods of warm [15 or 20 °C (59 or 68 °F)] and cold [2 °C (35.6 °F)] temperature stratification regimes in growth chambers. Embryo growth and viability, and seed moisture content were tested periodically during stratification. The best warm regime for embryo development, seed viability and germination after subsequent cold treatment was 15 °C (59 °F). The first “split” seeds, indicating incipient germination, were observed after 3 months of warm [15 °C (59 °F)] and 4 months of cold [2 °C (35.6 °F)] treatment, when average embryo length reached 6 mm (0.24 inch). Greenhouse germination of stratified seeds was as high as 80%. The results from this study indicate that good germination is possible when ginseng seeds are stratified indoors under a controlled environment and seeds can be made to germinate at any time of the year.

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David R. Dreesen and Robert W. Langhans

Abbreviations: CEGR, controlled environment growth rooms; HI, high irradiante levels; LI, low irradiance levels; MHI, medium high irradiance levels; MLI, medium low irradiance levels 1 Former graduate research assistant, currently research associate

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Norman R. Scott, Corinne Johnson Rutzke and Louis D. Albright

One of the deterrents to the commercial adoption of controlled-environment agriculture (CEA) on a broad scale is the significant energy cost for lighting and thermal environmental control. Advances in energy conversion technologies, such as internal combustion engines (ICs), microturbines and fuel cells, offer the potential for combined heat and power (CHP) systems, which can be matched with the needs of CEA to reduce fossil-based fuels consumption. A principal concept delineated is that an integrated entrepreneurial approach to create business and community partnerships can enhance the value of energy produced (both electrical and heat). Energy production data from a commercial dairy farm is contrasted with energy use data from two greenhouse operations with varying energy-input requirements. Biogass produced from a 500-cow dairy combined with a 250-kW fuel cell could meet nearly all of the energy needs of both the dairy and an energy-intensive 740-m2 CEA greenhouse lettuce facility. The data suggest CEA greenhouses and other closely compatible enterprises can be developed to significantly alter agriculture, as we have known it.

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Harry Janes, James Cavazzoni, Guna Alagappan, David Specca and Joseph Willis

A qualitative systems approach to controlled environment agriculture (CEA) is presented by means of several multi-institutional projects integrated into a demonstration greenhouse at the Burlington County Resource Recovery Complex (BCRRC), N.J. The greenhouse has about 0.4 ha of production space, and is located about 800 m from the about 40-ha BCRRC landfill site. A portion of the landfill gas produced from the BCRRC site is used for microturbine electricity generation and for heating the greenhouse. The waste heat from the turbines, which are roughly 15 m from the greenhouse, is used as the main heat source for the greenhouse in the winter months, and to desalinate water when heating is not required. Recovery of this waste heat increases the energy efficiency of the four 30-kW turbines from about 25% to 75%. Within the greenhouse, aquaculture and hydroponic crop production are coupled by recycling the aquaculture effluent as a nutrient source for the plants. Both the sludge resulting from the filtered effluent and the inedible biomass from harvested plants are vermicomposted (i.e., rather than being sent to the landfill), resulting in marketable products such as soil amendments and liquid plant fertilizer. If suitably cleaned of contaminants, the CO2 from the landfill gas may be used to enrich the plant growing area within the greenhouse to increase the yield of the edible products. Landfill gas from the BCRRC site has successfully been processed to recover liquid commercial grade CO2 and contaminant-free methane-CO2, with the potential for this gas mixture to be applied as a feedstock for fuel cells or for methanol production. Carbon dioxide from the turbine exhaust may also be recovered for greenhouse enrichment. Alternatively, algal culture may be used to assimilate CO2 from the turbine exhaust into biomass, which may then be used as a biofuel, or possibly as fish feed, thus making the system more self-contained. By recycling energy and materials, the system described would displace fossil fuel use, mitigating negative environmental impacts such as greenhouse gas emissions, and generate less waste in need of disposal. Successful implementation of the coupled landfill (gas-to-energy · aquaponic · desalination) system would particularly benefit developing regions, such as those of the Greater Caribbean Basin.

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Charles F. Forney and David G. Brandl

Solutions of glycerol and water provide a convenient and inexpensive system to control the relative humidity (RH) in small controlled-environment chambers. The relationship between the specific gravity (SG) of a glycerol-water solution and its equilibrium RH is described by the equation SG = [-0.189 (RH) + 19.9]0.0806. Gas can be humidified by bubbling it through jars containing solutions of glycerol-water with the desired equilibrium RH. The effects of flow rate, volume of solution, temperature, and pressure on the equilibrium RH are discussed.

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Mark G. Lefsrud and Dean A. Kopsell

Controlled plant growing systems have consistently used the standard earth day as the radiation cycle for plant growth. However, the radiation cycle can be controlled using automated systems to regulate the exact amount of time plants are exposed to irradiation (and darkness). This experiment investigated the influence of different radiation cycle periods on plant growth and carotenoid accumulation in kale (Brassica oleracea L. var. acephala DC.). Plants were grown in a controlled environment using nutrient solutions under radiation cycle treatments of 2, 12, 24 and 48 hours, with 50% irradiance and 50% darkness during each cycle. The radiation cycles significantly affected kale fresh weight, dry weight, percent dry matter, and the accumulation of lutein, β-carotene, and chlorophyll a and b. Maximum fresh weight occurred under the 2-hour radiation cycle treatment, whereas maximum dry weight occurred under the 12-hour treatment. Maximum accumulation of lutein, β-carotene, and chlorophyll a occurred with the 12-hour radiation cycle at values of 14.5 mg/100 g, 13.1 mg/100 g, and 263.3 mg/100 g fresh weight respectively. Maximum fresh weight production of the kale was not linked to increases in chlorophyll, lutein, or β-carotene. Consumption of fruit and vegetable crops rich in lutein and β-carotene carotenoids is associated with reduced risk of cancers and aging eye diseases. Increased carotenoid concentrations in vegetable crops would therefore be expected to increase the value of these crops.

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Jorge M. Fonseca, James W. Rushing, Nihal C. Rajapakse, Ronald L. Thomas and Melissa B. Riley

The purpose of this review is to promote a discussion about the potential implications of herb production in controlled environments, focusing on our recent works conducted with feverfew. Research suggests that the content of secondary metabolites in medicinal plants fluctuates with changing environmental conditions. Our studies with feverfew (Tanacetum parthenium [L.] Schultz-Bip., Asteraceae) lend support to this hypothesis. Feverfew plants exposed to different water and light conditions immediately before harvest exhibited changes in content of some secondary metabolites. The highest yield of parthenolide (PRT) was in plants that received reduced-water regimes. Phenolics concentration however, was higher in plants receiving daily watering. Light immediately before harvest enhanced accumulation of PRT, but reduced the phenolic content. Notably, PRT decreased at night whereas total phenolics decreased during the photoperiod and increased at night. PRT also increased with increased plant spacing. UV light supplementation increased PRT only in plants that had undergone water stress, whereas phenolics increased when UV was applied to continuosly watered plants. Clearly, production of medicinal plants under greenhouse conditions is a promising method for controlling levels of phytochemicals through manipulation of light and water as discussed here, and possibly other environmental factors such as temperature and daylength. However, better understanding of how the environment alter secondary metabolite levels is needed as it was revealed that manipulating the environment to favor increased accumulation of one group of phytochemicals could result in a decline of other key metabolites.