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Assessment and control of duckweed in the Maskinonge River, Keswick, Ontario

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dc.contributor.author Warren, Jeff.
dc.contributor.author Neil, John H.
dc.coverage.spatial Ontario
dc.coverage.spatial Lake Simcoe
dc.coverage.spatial Maskinonge River
dc.coverage.spatial Keswick
dc.date.accessioned 2018-07-24T16:53:37Z
dc.date.available 2018-07-24T16:53:37Z
dc.date.copyright 1992
dc.date.created 1988-12-01
dc.identifier.uri http://hdl.handle.net/10214/14017
dc.description.abstract An explosive growth of duckweed (Lemna minor, Wolffia sp.) covered 100% of the lower Maskinonge River in 1987 and created problems to commercial and public users. This condition is believed to have been the result of enriched stormwater flow from the surrounding agricultural land gaining access to the water course. During June, July and August 1987, rainfall was above the thirty year average and concentrations of ammonia, nitrate and phosphorus were the highest concentrations reported since implementation of the MOE water quality monitoring program at the Woodbine Avenue location. There has been a recent increase in the acreage of sod farms in the Maskinonge River watershed. The amount of fertilizer applied to sod is significantly greater than quantities used for other agricultural crops. For these reasons changes in land fertilizer use was probably a contributing factor to the problem in 1987 and will be in the future unless corrective action is taken. The study reported herein addresses the cause of the problem and means for future control. Two means to control the problem are discussed; improvement in water quality and the use of herbicides as a preventative measure. Water quality improvement will require the identification of specific sources of nutrients to the watercourse and action to reduce or eliminate them. An objective for water quality equivalent to the Black River is proposed. Herbicide control using Reglone A in nursery areas was found to be an effective means of preventing duckweed growth. The report recommends that a detailed evaluation of all fertilizer use and other potential sources of plant nutrients be made by an enforcement agency and that best available agricultural practice be required as the means to achieve the proposed water quality objective. A water sampling program is recommended to improve the data available on water quality and to identify specific sources of nutrient inputs. It is recommended that herbicide control be continued as a preventative measure until such time as water quality improvements ensure that the 1987 duckweed problem will not reoccur. An estimate of cost to implement the water quality monitoring and herbicide control programs are provided.
dc.format pdf
dc.language.iso en
dc.publisher Queen's Printer for Ontario
dc.relation.ispartofseries Technical Report Imp. B.6
dc.rights Queen's Printer for Ontario, Crown Copyright, Non-Commercial Use Permitted
dc.rights.uri https://www.ontario.ca/page/copyright-information-c-queens-printer-ontario
dc.subject duckweed en_US
dc.subject Maskinonge River en_US
dc.subject water quality en_US
dc.subject nitrate en_US
dc.subject phosphorus en_US
dc.subject fertilizer en_US
dc.subject herbicide en_US
dc.title Assessment and control of duckweed in the Maskinonge River, Keswick, Ontario en
dc.type Technical Report
dc.rights.holder Queen's Printer for Ontario
dc.contributor.affiliation Limnos Ltd.


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