How Organic Fertilizers can be used as a Plant Nutrient Source in Hydroponics: A Review

Sustainable crop production can be achieved by integrating the concept of modern agriculture with hydroponics for plant production and organic agriculture with the use of organic fertilizer as an alternative to the chemicalbased nutrient solution. Organic fertilizers contain a significant amount of essential nutrients needed by the plant for growth and development. Various approaches have been studied to test the viability of organic fertilizer as a nutrient source in hydroponics, such as replacing inorganic substrates with organic substrates, partial replacement, and full replacement of chemical-based nutrient solutions with organic fertilizers. Full replacement of nutrient solutions with organic fertilizers is deemed to be the most sustainable approach. However, unlike nutrient solution, which has an established optimum operation parameter, organic fertilizer as a nutrient solution in hydroponics faces several challenges, such as variability of the quality of organic fertilizers, nutrient management and optimization of the operating parameters. This review provides a general overview of the various approaches to utilize organic fertilizer as a plant nutrient source in hydroponics. In addition, this review provides a synthesis of hydroponics and its applicability to sustainable production, nutrient content of commonly used organic fertilizers and chemical-based nutrient solutions, a comparison of the plant growth and quality using organic fertilizer and chemical-based nutrient solutions and important operating parameters on utilizing organic fertilizers in hydroponics.