Ebb and flood nutrient delivery system for sustainable automated crop production

For more than 40 years ebb and flood irrigation and nutrient delivery systems have been nurturing crops within greenhouse controlled environments. Bedding plants, potted plants, cut flowers and even tomatoes have been produced. An overview and critical discussion of the delivery of water, dissolved oxygen and plant nutrients to the root zone of the crop using the ebb and flood principles is discussed in this article. Ebb and flood systems have functioned within automated crop production systems from table transport devices to concrete floor heating systems. The benefits were the easily manageable means to uniformly provide water, dissolved oxygen and plant nutrients to the root zone of the crop, without requiring a fixed plumbing connection, either for inflow during flood or for drainage at ebb. The results were effective transport of water, nutrients and oxygen from the bottom of the root zone upwards, and with saturation of the bottom of the root zone, allowing minimal flushing of nutrients and other dissolved substances from the root zone. All unused irrigation water was collected and returned to storage for future use, creating a recirculating hydroponic system which conserved water and nutrients and directly benefited the environment by eliminating discharge. Fundamental design criteria and operation management practices; integration with concrete floor heating system; and, examples of successful applications are discussed, as are limitations and future applications.