Effect of Ultraviolet Light Exposure and Compost Tea Supplementation on Growth, Antioxidant Activities, and Microbiome of Hydroponically Grown Mustard Greens

Abstract

Hydroponic food production in greenhouses is challenged by reduced exposure to ultraviolet (UV) light and beneficial soil microorganisms, which predisposes plants to antioxidant deficiencies and disease susceptibility. The objective of this study was to investigate the effects of UV light exposure and compost tea treatment on hydroponically grown plants. Garnet Giant mustard greens were hydroponically grown in both indoor and outdoor greenhouse settings, with and without UV light blocking and supplementation of compost tea. Plants grown outside in greenhouses produced more dry mass than those grown indoors. Compost tea supplementation boosted nitrogen and mineral accumulations in the absence of UV-blocking. Increased UV exposure resulted in more red pigmentation and higher antioxidant activities of the mustard greens, while compost tea supplementation reduced antioxidant activities. Compost tea treatment increased beneficial bacteria and decreased fungal pathogens. Overall, exposure to UV radiation and beneficial microorganisms improved the performance and nutrient profile of the mustard greens.

Combined effect of an agro-industrial compost and light spectra composition on yield and phytochemical profile in mizuna and pak choi microgreens

“…This indicates that increasing the percentage of compost leads to a decrease in anthocyanins. In this respect, the application of compost tea on hydroponic mustard leaves [ 36 ], and vermicompost on fenugreek plants [ 37 ], reduced anthocyanin content, compared to control treatments; fact that it could be reported through anthocyanin synthesis was inhibited by nitrogen increase [ 38 ], which corresponds to the results we have obtained with higher proportion of compost in the growing media combination, that showed higher amount of nitrogen ( Table 1 ; Table 5 ; Table 6 ).…”

Nutritional and microbiological effects of vermicompost tea in hydroponic cultivation of maple peas (Pisum sativum var. arvense L.)

“…The organic waste ingested by earthworm provides energy for microbial growth (Ravindran et al, 2016 ). Lu et al ( 2022 ) experimentally confirmed that in the absence of UV blockage, VCT supplementation promoted nitrogen and mineral accumulation in mustard plant, increased beneficial bacteria, and reduced fungal pathogens. Therefore, adding VCT can influence the microbial community and promote plant growth.…”

Effect of Compost Tea in Horticulture

“…The influence of compost tea from Oyster Mushroom Waste on the growth and the flavonoid content in the black rice was evaluated by Khoerunnisa et al [71]; the results displayed an increase in both the growing rate and flavonoid content depending on the treatments administered to the plants, in particular it was showed that the administration of compost tea of 45% lead to best rice growth, while the concentration of 35% lead to a best flavonoids content [71]. An example of the combined use of compost tea with other treatments is given by Lu et al [72], who investigated how hydroponically grown plants respond to UV light exposure and compost tea treatment. Garnet Giant mustard greens were grown both indoors and outdoors, with or without UV light blocking and with or without the addition of compost tea.…”

“…The mustard greens' antioxidant capacities increased with increased UV exposure, while being supplemented with compost 9 of 13 tea decreased their antioxidant capacities. Treatment with compost tea enhanced good bacteria and lowered pathogenic fungi [72]. The impact of organic fertilizer solutions on the productivity, quality, and antioxidant capacity of hydroponically grown cucumber (Cucumis sativus L.) fruits produced in a greenhouse has been studied by Santiago-López et al [73].…”

“…Compost tea Wild ginger Maximize accumulation of minerals, phytochemicals, and antioxidant [68] Compost tea and potassium humates Lettuce Increased concentration of minerals, primarily amino acids, saccharides, and antioxidants [69] Compost tea and humic acids Faba bean Increased nutritional content, total sugars, and crude protein [70] Compost tea from Oyster Mushroom Waste Black Rice Increased growth rate and flavonoid content [71] Compost tea and UV exposure Garnet Giant Mustard Increased nitrogen and mineral accumulation [72] Compost and vermicompost tea Cucumber (Cucumis Sativus L.) Increased antioxidant capacity [73] Compost tea Grape Increased N, P, K, and chlorophyll content in petioles, higher production, and total sugar and anthocyanin content in grape skins [74] Compost tea Blueberry Increased K concentration in leaves and fruit, increased Na content of leaves [75] Humic acids isolated from vermicompost Ananas Improved growth, increased nutrient content (N, P, K, Ca, Mg) [76]…”