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Title: Impact of Fertigation versus Slow Release Fertilizer Formulations on Nitrate Enrichment of Nursery Drainage Water

Author
item WILSON, CHRIS - University Of Florida
item Albano, Joseph

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2010
Publication Date: 4/1/2011
Citation: Wilson, C., Albano, J.P. 2011. Impact of Fertigation versus Slow Release Fertilizer Formulations on Nitrate Enrichment of Nursery Drainage Water. HortTechnology. 21:176-180.

Interpretive Summary: In the production of ornamental crops, nitrogen supplied in fertilizer can leach through the pot and contaminate water resources. The ecology of natural ecosystems that receive nitrogen contaminated water can change through a process called eutrophication. To reduce the risk of excess nitrogen in water resources on a horticultural crop operation, a study was conducted to compare nitrogen leaching rates of a controlled-release fertilizer (solid) versus a soluble fertilizer (liquid). What we learned was that using a controlled-release fertilizer can reduce the amount of nitrogen in leachate by over 90% versus a soluble fertilizer. The significance of this work is that growers located within nitrogen-limited watersheds facing nitrogen water quality regulations may be able to use controlled-release fertilizer formulations as a potential tool (in addition to appropriate application rates and irrigation management) for reducing production impacts on water quality.

Technical Abstract: Nitrate-nitrogen losses in surface drainage and runoff water from ornamental plant production areas can be significant. In nitrogen-limited watersheds discharge of nitrogen (N) from production areas can have significant, negative impacts on non-target aquatic systems. This study monitored nitrate-N concentrations in production area drainage water originating from a foliage plant production area. Concentrations were monitored during the transition from 100% reliance on fertigation using urea and nitrate-based soluble formulations (SF) to a nitrate-based controlled release formulation (CRF). During the SF use period, NO3-N concentrations ranged from 0.5-322.0 ppm, with a median concentration of 31.2 ppm. Conversely, nitrate-N concentrations during the slow-release fertilization program ranged from 0-147.9 ppm with a median concentration of 0.9 ppm. Nitrate-N concentrations in drainage water during the CRF program were reduced by 94-97% at the 10th, 25th, 50th, 75th, 90th, and 95th percentiles relative to the SF fertilization program. Nitrate-N concentrations in drainage water from foliage plant production areas can be significantly reduced by using CRF fertilizer formulations relative to SF formulations/fertigation. Similar results should be expected for other similar, potted crops. Managers located within nitrogen-limited watersheds facing nitrogen water quality regulations should consider use of CRF fertilizer formulations as a potential tool (in addition to appropriate application rates and irrigation management) for reducing production impacts on water quality.