Nutrients Recycling in Hydroponics: Opportunities and Challenges toward Sustainable Crop Production under Controlled Environment Agriculture, Volume II (2024)

This Research Topic is part of the Nutrients Recycling in Hydroponics: Opportunities and Challenges toward Sustainable Crop Production under Controlled Environment Agriculture series.

Hydroponics is a method of growing plants in water, or in an inert media, without soil and using mineral nutrient solutions in a water solvent to supply complete nutrition for plant growth. Hydroponics can give precise control over plant growth parameters which can lead to yield and quality improvement. In principle, nutrient solutions used in hydroponics can either be reused or discarded. Nowadays, the cultivation of leafy vegetables, medicinal herbs, and other plants with pharmaceutical value are commercially grown under recycled hydroponics with controlled environments.
In recycled hydroponics, nutrient solutions passed through the growing medium are collected into a reservoir and reused repeatedly. In this system, both water and mineral nutrients are used efficiently and therefore minimizes the wastage of fertilizer and the environmental damage. Hydroponic systems have been widely used in controlled environment agriculture (CEA) facilities, or plant factories, using artificial grow lights, such as light-emitting diodes (LED), Hybrid Electrode Fluorescent Lamps (HEFL), fluorescent lamps (FL), etc. Management of the hydroponic nutrient solution composition, along with the adjustment of environmental conditions may enhance the final nutritional quality, regulate bioactive compounds, increase antioxidants, and other phytochemical content.
Hydroponics may however be challenged by the accumulation of root exudates that affect plant growth and reduce crop yield and quality. Lower growth and yield performance of several crops including lettuce, strawberry, several leafy vegetables, and ornamentals have been reported in recycled hydroponics. In fact, retardation of growth and yield of crops grown in recycled hydroponics because of increased concentration of phytotoxic root exudates may be observed. Certain phytotoxic chemicals may have a significant impact on plant growth. Moreover, recycled nutrient solutions often require sterilization to minimize pathogen loads. In this regard, chemicals and physical treatments such as hypochlorite, ozone, and UV-light, are being used for sterilization.
The present Research Topic invites submissions of Original Research, Reviews, and Methods manuscripts falling within one or more of the subjects below. Perspective and Commentary articles about existing research are also welcome.
• Recycled hydroponics for growing high-value vegetables, medicinal and aromatic plants under greenhouse, Controlled Environments Agriculture (CEA).
• Management of hydroponics nutrient solution composition and concentration for agricultural yield maximization and quality improvement of the product, together with relevant physiology experiments towards an understanding of the mechanisms behind this.
• Modification of environmental controls for the enhancement of nutritional quality, regulation of bioactive compounds, antioxidants, and other target chemical components of the crop, together with relevant physiological experiments.
• Use of artificial growth lights like LED, HEFL, and FL for efficient production and quality improvement of the crops.
• Limitations of the reuse of culture solutions under successive cultivation in indoor farming, and plant factories.
• Development of autotoxicity due to the accumulation of phytotoxic root exudates in recycled solutions.
• Methods of recovering autotoxicity from the reuse of nutrient solutions for sustained crop yield and quality.
Please note that descriptive studies that report responses of growth, yield, or quality to agronomical treatments will not be considered if they do not progress physiological understanding of these responses.
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.