GOHYDRO D4.2 Evaluation results from experiments in semi-controlled realistic installations
Creators: name: Zervas, Panagiotis
name: Koukourikos, Antonis
name: Rusu, Teodor
name: Moraru, Paula
name: Bhim Ghaley
name: Cowden, Reed
name: Makarona, Eleni
Publisher: name: Zenodo
Year: 2023

description: The activity <em>T4.2 Experimentation in controlled realistic installations</em>, had as an objective - <em>To carry out pilot trials and provide feedback for the refinement and calibration of the GOhydro platform</em>. In order to fulfill this objective USAMV Cluj built 2 GOhydro platforms, identical, to be able to do experiments in parallel, both in semi-controlled conditions and in operational conditions. The GOhydro platform was built considering the recommendations of <em>Deliverable 2.1 Multi-modal Sensor Kit Specifications and Requirements</em>. To achieve semi-controlled conditions, one of the platforms was included in the grow tent Eden Grow XL Growbox Growtent homegrowing with dimensions of 240 x 120 x 200 cm. USAMV performed the test with the GOhydro platform in semi-controlled conditions, with 2 species: basil (2 varieties: Germaline Basilic Bio and Basil Grand Vert) and lettuce (3 varieties: Paris White, Little Gem and Lolla Rossa). The methodology used for the research was derived from deliverable <em>D4.1: Trial protocols for microgreens production in hydroponic units</em>. The growing conditions of the two species of microgreens (basil and lettuce) are specific to semi-controlled conditions, using the Eden Grow plant growing tent. Thus, a temperature was kept in the atmosphere with a maximum oscillation of 3-4 °C, an atmospheric humidity oscillation of 8-10 %, and respectively a constant amount of light (of 1217 μmolm<sup>-2</sup>s<sup>-1</sup>). The irrigation water had a constant temperature of 19-21 °C, a pH of 6.8-7, an electrical conductivity between 1.4-1.5 mS, and respectively a quantity of 6.4-6.5 mg L<sup>-1</sup> dissolved oxygen. Among the 2 species tested, lettuce ensures distinctly significantly positive Fresh Weight production. By comparison with the Duncan test, it results that the best amount of Fresh Weight is provided by Lettuce - Lolla Rossa, with 889.86 g/m<sup>2</sup>. Basil provides the highest amount of Dry Weight, with a very distinctly significantly positive difference. The variability of the data recorded for total phenols is very high, and the statistical processing did not highlight results with a significant difference. Lettuce contains 98-107.33 mg/kg, and basil 141-186.33 mg/kg total phenols. From the morphological analysis of plant development, both in basil and in lettuce, no disease attack is registered, due to the maintenance of the health of the water in the feed basin and a quantity of around 6.4-6.5 mg L<sup>-1</sup> of dissolved oxygen. An exception is made in the case of lettuce, the Paris White variety, which registers until the end, grade 3 in the degree of attack. This is due exclusively to this variety in which the seed had an inadequate quality for the production of hydroponic microgreens. In conclusion, the experiment in the GOhydro platform, in semi-controlled conditions (plant growth tent) shows productive pathways to ensure an optimal development of hydroponically grown microgreens. It is very important to control vegetation factors, temperature, atmospheric humidity, etc. However, cultivation technology is very important. This resulted in some useful recommendations such as necessity to know and determine the actual germination of the seeds. Following the work conducted in Work Package 1 with identifying ideal growing conditions using environmental controls for Microgreen production, we conducted controlled environment experiments in the pilot sites of Denmark and Romania to test and validate these previous results. In Denmark, we grew six different species of Microgreens: Basil, Coriander, Kale, Kohlrabi, Mustard, and Radish. These Microgreens were experimented on using multiple factors, such as Fertilization (yes or no), Light Recipe (of which there were five total recipes from two different types of lights), and Seeding Density (high and standard). The experiment was conducted as a complete random block design with highly controlled environmental conditions, such as air temperature, relative humidity, pH, EC, and light incidence. We showed that there were highly significant differences between all tested species, and as a result we conducted statistical analyses at a higher resolution to parse apart the influence of our different experimental factors on each individual species. Overall, we found much species-specific variation in accumulation of secondary metabolites due to experimental factors. However, we did find some general trends whereby Phenolic accumulation was best explained by Light Recipe: specifically, it was the High Far Red recipe which performed the best. However, there was a tradeoff in this case, as the High Far Red produced the most Phenolics, but also the least amount of Antioxidants. For Anthocyanins, we found it was more nuanced: we saw that light intensity, fertilization, and seeding density, depending on the species, explained the most variation. The same dynamic response was seen for Flavonoids as well. Therefore, these validation experiments have shown the sensitivity of these six different Microgreen species to different combinations of our experimental factors. Overall, we did not find any single best recipe, but we did identify species-specific responses and some general tradeoffs that were shown. These results can be instructive for producers that have specific production outcomes in mind, and can be used to tailor different efforts in combination with our previous deliverables on Microgreen production methodologies.