The cost of irrigation sources and water treatment in greenhouse production

Uncertainty about the cost of water treatment is a potential barrier to adoption of irrigation treatment and recycling. The objective of this study was to estimate the cost of irrigation-water filtration and sanitation based on a survey of 11 greenhouse operations. Screen filtration of ebb-and-flood irrigation water cost ($0.02-$0.17 per 1000 gal) less than filtration using synthetic fiber rolls ($0.08-$2.97 per 1000 gal). Technologies to control pathogens and biofilm ranged between $0.07 per 1000 gal for chlorine gas to $1.00 per 1000 gal for a copper ionization system. Irrigation water sources ranged in cost from $0.02 per 1000 gal for pond water to $6.43 per 1000 gal for municipal water. Sanitation increased this cost by $0.07-$1.00, and water-soluble fertilizers added $3.80. Case studies of three growers illustrated that water quality issues such as equipment clogging or plant pathogens can increase production cost, and in many cases, water treatment and recirculation provide economic savings. Our analysis emphasizes that the cost and quality of the initial water source, the cost of production losses from quality issues, and the cost of treatment should all be considered to make informed decisions on irrigation water sources and system design.