Park & Open Space Fertilizer / Chemical Application Programs

Minimization of and training for chemical application

Fertilizers, herbicides, and insecticides have various ecological effects, toxicity, and chemical fate and transport based on the product’s chemical components. Depending on the chemicals’ characteristics, they can have unintended harmful effects on terrestrial and aquatic plants and animals, and can end up in our soil, water, and air. Nitrates from fertilizers can migrate through the soil profile and contaminate ground water supplies beyond safe drinking water levels.

Phosphorus from fertilizers contributes to eutrophication of surface water bodies that depletes oxygen levels and can lead to fish kills. This fact sheet provides guidance on program development for minimizing fertilizer and pesticide application.

Benefits / Pollution Reduction

Practicing proper fertilizer, herbicide, and pesticide application reduces the risk of these materials being transported by stormwater to downstream water bodies. Minimizing chemical use by employing best management practices (BMPs) for both application and material handling helps to eliminate a significant cause of stormwater pollution. Some BMPs have the potential to reduce costs associated with grounds keeping and maintenance, while improving the aesthetics and vegetative health of grounds where they’re implemented.

Program Development & Implementation

Programs designed to manage and minimize chemical application typically include a combination of the elements identified below. The BMPs and chemical alternatives discussed can provide the content for training programs and public education materials.

Integrated Pest Management

Integrated pest management (IPM) is a pest control system that employs mechanical, biological, cultural, and/or chemical mechanisms as determined by a thorough evaluation of the conditions rather than addressing every condition with chemicals.

The following are IPM strategies:

  • Cultural control – selected timing and location of plantings to avoid pests
  • Host resistance – planting vegetation that is resistant to pests
  • Mechanical control – weeding; setting insect traps
  • Biological control – stocking beetles to attack purple loosestrife; protecting naturally-occurring insect predators, parasites, and pathogens
  • Chemical control – using the least toxic pesticides available wherever possible

I PM strategies are employed only when pest populations reach an unacceptable economic or aesthetic threshold.

Chemical Preparation and Handling Best Management Practices

The following guidelines should be followed when preparing and handling chemicals:

  • Select the least toxic products available to minimize waste and applicator exposure
  • Use products only as directed, reading and following all labels
  • Inspect, maintain, and calibrate equipment used for mixing and application
  • Prepare only as much herbicide/pesticide as is needed
  • Be prepared with cleanup materials to cleanup spills immediately; use dry cleanup methods (e.g. squeegee and dust pan) rather than hosing down the spill site
  • Close containers tightly after each use, even if planning to reopen them soon
  • Store chemicals safely in a ventilated, well lit area that is away from drinking water wells or any other permanent or intermittent water bodies
  • Dispose of rinse water properly and recycle containers properly. For pesticides, triple rinsing or pressure rinsing with reuse of rinse water for future pesticide applications is recommended by the University of Minnesota. Proper rinsing of pesticide containers is also a requirement of Minnesota State and federal law.
  • Monitor all fertilizer/pesticide application quantities and sites in order to provide guidance for future treatments
  • Keep products in their original containers and mark the date of purchase on each container. Use older materials first.

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