History of Controlled Environment Horticulture: Indoor Farming and Its Key Technologies

The most recent platform for protected horticultural crop production, with the shortest history to date, is located entirely indoors, lacking even the benefit of free, natural sunlight. Although this may not sound offhand like a good idea for commercial specialty-crop production, the concept of indoor controlled-environment plant growth started originally for the benefit of researchers—to systematically investigate effects of specific environmental factors on plant growth and development in isolation from environmental factors varying in uncontrolled ways that would confound or change experimental findings. In addition to its value for basic and applied research, it soon was discovered that providing nonlimiting plant-growth environments greatly enhanced crop yield and enabled manipulation of plant development in ways that were never previously possible. As supporting technology for indoor crop production has improved in capability and efficiency, energy requirements have declined substantially for growing crops through entire production cycles in completely controlled environments, and this combination has spawned a new sector of the controlled-environment crop-production industry. This article chronicles the evolution of events, enabling technologies, and entrepreneurial efforts that have brought local, year-round indoor crop production to the forefront of public visibility and the threshold of profitability for a growing number of specialty crops in locations with seasonal climates.

History of Controlled Environment Horticulture: Ancient Origins

In the first century CE, two Roman agricultural writers, Lucius Junius Moderatus Columella and Gaius Plinius Secundus (Pliny the Elder), referred to proto-greenhouses (specularia) constructed for the Emperor Tiberius (42 BCE–37 CE) presumably adjacent to his palace, the Villa Jovis on the Isle of Capri. Pliny stated in Historia Naturalis (Book 19, 23:64) that the specularia consisted of beds mounted on wheels that were moved into the sun, and on wintry days withdrawn under the cover of frames glazed with transparent stone (lapis specularis) to provide fruits of cucumis. According to Pliny, this was “a delicacy for which the Emperor Tiberius, had a remarkable partiality; in fact there was never a day on which he was not supplied it.” The cucumis fruits described by Columella and Pliny, long mistranslated as cucumbers, Cucumis sativus, were in fact long-fruited melons, Cucumis melo subsp. melo Flexuosus Group. They are known today as vegetable melons, snake melons, and faqqous, and were highly esteemed in Rome and ancient Israel.

Extraction of underwater fragile artifacts: research status and prospect

There are still many difficulties in the recovery and long-term preservation of underwater archaeological artifacts, in situ preservation should be the first choice before further procedures are considered. However, the materials, preservation status, and preservation environment of underwater artifacts are diverse, resulting in many fragile artifacts facing difficult situations. In order to prevent serious damage, it is a safe protective strategy to preserve them in a controlled environment for a long time after excavation. Extraction and transfer of fragile cultural relics are vital parts of this strategy. Due to the complexity of the underwater environment and the vulnerability of fragile artifacts, safety in extraction and transfer still faces enormous challenges. Researchers have developed new materials and technologies to tackle this problem. This paper focuses on introducing and developing prospects to different preservation techniques for fragile artifacts from underwater sites.

How real is real enough? Participant feedback on a behavioral simulation used for information-seeking behavior research

A challenge of studying information-seeking behavior in open web systems is the unpredictability of those systems. One solution to counteract this issue is employing a simulation to ensure experimental control. However, concerns arise over the realism of such an environment. This paper assesses the realism of a behavioral simulation used to study the evaluation behavior of 175 students from fourth grade through graduate school. We assess realism through the examination of targeted participant feedback about what would have made the simulated environment and tasks more realistic to these participants. Based on this feedback, we reflect on decisions made in designing the simulation and offer recommendations for future studies interested in incorporating behavioral simulation in their research design. We find that a thoughtfully designed simulation can elicit naturalistic behavior when the controlled environment is designed to be realistic in meaningful ways. Because the simulation does not have to perfectly match reality to elicit these behaviors, designing a simulation that is real enough is an effective method to study information-seeking behavior.

Morphological and Physiological Screening to Predict Lettuce Biomass Production in Controlled Environment Agriculture

Fast growth and rapid turnover is an important crop trait in controlled environment agriculture (CEA) due to its high cost. An ideal screening approach for fast-growing cultivars should detect desirable phenotypes non-invasively at an early growth stage, based on morphological and/or physiological traits. Hence, we established a rapid screening protocol based on a simple chlorophyll fluorescence imaging (CFI) technique to quantify the projected canopy size (PCS) of plants, combined with electron transport rate (ETR) measurements using a chlorophyll fluorometer. Eleven lettuce cultivars (Lactuca sativa), selected based on morphological differences, were grown in a greenhouse and imaged twice a week. Shoot dry weight (DW) of green cultivars at harvest 51 days after germination (DAG) was correlated with PCS at 13 DAG (R2 = 0.74), when the first true leaves had just appeared and the PCS was <8.5 cm2. However, early PCS of high anthocyanin (red) cultivars was not predictive of DW. Because light absorption by anthocyanins reduces the amount of photons available for photosynthesis, anthocyanins lower light use efficiency (LUE; DW/total incident light on canopy over the cropping cycle) and reduce growth. Additionally, the total incident light on the canopy throughout the cropping cycle explained 90% and 55% of variability in DW within green and red cultivars, respectively. Estimated leaf level ETR at a photosynthetic photon flux density (PPFD) of 200 or 1000 µmol m−2 s−1 were not correlated with DW in either green or red cultivars. In conclusion, early PCS quantification is a useful tool for the selection of fast-growing green lettuce phenotypes. However, this approach may not work in cultivars with high anthocyanin content because anthocyanins direct excitation energy away from photosynthesis and growth, weakening the correlation between incident light and growth.

Photosynthetic efficiency, growth and secondary metabolism of common buckwheat (Fagopyrum esculentum Moench) in different controlled-environment production systems

Light-emitting diodes (LEDs) and high-pressure sodium lamps (HPS) are among the most commonly used light sources for plant cultivation. The objective of this study was to evaluate the effect of two controlled-environment production systems differing in light sources on growth, photosynthetic activity, and secondary metabolism of common buckwheat. We hypothesized that LED light with the majority of red and blue waves would increase physiological and biochemical parameters compared to sunlight supplemented with HPS lamps. The experiment was performed in a phytotronic chamber (LEDs) and in a greenhouse (solar radiation supplemented with HPS lamps as a control). The effects were analyzed at the flowering phase with biometric measurements, leaf chlorophyll index, the kinetics of chlorophyll a fluorescence, content of soluble carbohydrates and phenolics in the leaves. Applied LED light decreased the biomass but stimulated the production of phenolics compared to control plants. In control plants, a positive correlation between flavonoid content and energy dissipation from photosystem II (DIo/CSm) was found, while in plants under LEDs total pool of phenolic content correlated with this parameter and the quantum yield of electron transport (φ Ro and ψ Ro) was lower than that of the control, probably affecting buckwheat biomass.

A PROENVIRONMENTAL VALUE CONSTRUCT TO DEAL WITH PLASTIC POLLUTION

Plastics are man-made synthetic materials. They are made mostly from crude oil even though natural gas and coal could also be used for manufacturing plastics. The multiplicity of its uses together with its versatile properties has made it indispensable to modern living. The average life of plastics differs in various industrial sectors. The generation of waste depends on the mean-product lifetime of the product into which plastics have been integrated. And when this waste is not handled properly (recycled or incinerated under controlled environment), the problem of pollution emerges. Plastics in the form of microplastics have been found in food chains as well, threatening human wellbeing. A model to better understand the source - use and afteruse of plastics is the central focus of this article. It looks at the need for building a sustainable model to deal with plastic pollution.

​Study of the Zootechnical Performance of Tilapia cabrae and Oreochromis schwebischi in a Controlled Environment: The Case of the Mbolet Fish Farm in Lambaréné, Gabon

Background: The study of the zootechnical performance of Tilapia cabrae and Oreochromis schwebischi was carried out at the Mbolet fish farm in Lambaréné in Gabon in order to evaluate the growth and reproductive performance of these two species. Methods: For this purpose, 226 fish (113 of T. cabrae with an average weight of 30.55±9.5 g and 113 O. schwebischi with an average weight of 20.64±10.5 g), were distributed in four 6 m2 tanks with two replicates per species for the growing phase which lasted 60 days. For the reproductive phase, 42 selected mature fish, including 6 males and 36 females of each species, were placed in six 2 m2 ponds with three replicates per species for 78 days. Result: The survival rate, the number of reproductions per species and the absolute, relative and system productivities were determined. It was found that the average weight gain, daily individual growth and specific growth rate were significantly (p less than 0.05) higher in T. cabrae, 48.1±5.51 g, 0.8±0.092 g/day and 1.57±0.066% g/day respectively, than in O. schwebischi, 27.11±9.23 g, 0.45±0.15 g/day and 1.38±0.051% g/day respectively. At the end of reproduction, the absolute productivity of T. cabrae (234.75±24.71 larvae/female/egg-laying) was significantly higher (p less than 0.05) than that of O. schwebichi (104.68±46.64 larvae/female/laying). System productivity was significantly higher (p less than 0.05) in O. schwebichi (11.34±2.29 larvae/m2/day) compared to that of T. cabrae (4.12±1.73 larvae/m2/day). Thus, on a fish farm, the use of these species may be possible.