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Title: NUTRIENT RELEASE FROM CONTROLLED-RELEASE FERTILIZERS IN ACID SUBSTRATE IN A GREENHOUSE ENVIRONMENT: II. LEACHATE CALCIUM, MAGNESIUM, IRON, MANGANESE, ZINC, COOPER, AND MOLYBDENUM CONCENTRATIONS

Author
item BLYTHE, EUGENE - UC-RIVERSIDE
item MERHAUT, DONALD - UC-RIVERSIDE
item NEWMAN, JULIE - UC-RIVERSIDE
item Albano, Joseph

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2006
Publication Date: 6/1/2006
Citation: Blythe, E.K., Merhaut, D.J., Newman, J.P., Albano, J.P. 2006. Nutrient release from controlled-release fertilizers in acid substrate in a greenhouse environment: ii. leachate calcium, magnesium, iron, manganese, zinc, cooper, and molybdenum concentrations. HortScience.41(3):788-793.

Interpretive Summary: Controlled release fertilizers (CRF) are designed to provide a steady supply of nutrients to plants over a specificed time. Nutrient release for such fertilizers is typically dependent on temperature with an increasing temperature yielding an increase in nutrient release. In the project we studied the release characteristics for calcium, magnesium, iron, manganese, zinc, copper and molybdenumover a 47-week period for four commonly used CRF (Osmocote, Nutricote, Polyon, and Multicote). We found that the release rates for the selected nutrients were relatively high during the first 10 to 20 weeks of the study, and then gradually decreased during the remaining portion of the experiment. Few differences were observed among fertilizer types.

Technical Abstract: Leachate from containerized substrate containing one of four different controlled-release fertilizers (Osmocote, Nutricote, Polyon, or Multicote) were monitored for concentrations of Ca, Mg, Fe, Mn, Zn, Cu and Mo during a 47-week period. Environmental and cultural practices simulated an unheated greenhouse production program typically used for low-nutrient-requiring crops such as azalea and camellia. Leachate concentrations of all nutrients were relatively high during the first 10 to 20 weeks of the study, and then gradually decreased during the remaining portion of the experiment. Few differences were observed among fertilizer types. Of the elements monitored, only Fe and Mn leachate concentrations were above critical concentrations as provided in the Clean Water Act by the U.S. EPA.