Challenges of using organic fertilizers in hydroponic production systems

摘要

In countries that allow organic food production to occur in hydroponic production systems, use of organic nutrient sources is increasing for several reasons, including the ability to obtain organic certification for food crops and/or to reduce nitratelevels in crops that are consumed by humans. These studies report on the production of butterhead lettuce {Lactuca sativa L. 'Rex') in nutrient film technique (NFT) culture with conventional fertilizer versus a formulated organic fertilizer product line. As an overview from our experiences, using organic instead of conventional fertilizers in recirculating culture generates new challenges for growers: achieving plant yields that occur with inorganic nutrient sources is more difficu pH fluctuates more dramatically; only limited products that meet organic certification requirements are available to adjust pH; electrical conductivity readings are not an optimal method on which to base nutrient additions; and organic nutrient sources may contain excessive (e.g., micronutrients) or unneeded (e.g., sodium) constituents that necessitate routine ion-specific monitoring.