Safe Fertilizers

Tuesday, November 27, 2012

To commercial farmers, fertilizers are a vital ingredient in the success of their harvests.  Fertilizers fortify crops so that yields are larger and hardier, and they replace essential nutrients to soils depleted by harvests.  To home gardeners and landscapers, fertilizers beautify lawns and increase productivity of vegetable and flower gardens. Unfortunately for both commercial and residential users, fertilizer use can be dangerous.

The potential hazards of fertilizer stem from its composition. Two of the most common fertilizers, urea and ammonium nitrate, can be harmful if used in any manner that deviates from label instructions.

Urea and ammonium nitrate are nitrogen-based fertilizer products. (According to the Canada Department of Agriculture, urea is the most used dry source of nitrogen for plants and crops around the world.) Although nitrogen is produced in nature, it is not present in quantities large enough to sustain the high yields necessary to commercial farmers. Hence, nitrogen-based fertilizer products are applied. But dangers may arise when large quantities of these fertilizers are applied to fields and heavy rainfalls wash the concentrated ammonium into surface water. Air quality is another concern, as ammonia in a confined space can contaminate the air. Another danger is the criminal misuse of ammonium nitrate: It has been used in the production of bombs and methamphetamine.

In 2003, the Canadian Fertilizer Institute (CFI) and other industry leaders established the Fertilizer Safety Security Council (FSSC) to promote the safe and secure manufacturing, handling, storage, transportation and application of fertilizers with the intent of protecting people from the risks associated with their accidental release or criminal misuse. This organization offers information, training and counsel to agricultural management and workers, agri-retailers and the general public.

In addition, the Canadian Food Inspection Agency has instituted the federal Fertilizers Act and Regulations, which require that fertilizer and supplement products imported into or sold in Canada be safe for humans, plants, animals and the environment, and that they be properly labeled. This mandate covers a wide range of products sold for agricultural, commercial, and home and garden purposes. The manufacture, proper use and safe disposal of these products are controlled by provincial and municipal rules and regulations.

Still, many residential and commercial growers turn to organic fertilizers to avoid the potential hazards of urea and ammonium nitrate. Although these fertilizers tend to work more slowly, they are growing in popularity due to the increasing awareness of the need for environmental stewardship. Common organic ingredients include the following:

  • Poultry, cow, horse and sheep manure
  • Fish
  • Compost
  • Blood meal
  • Bone meal
  • Plant nutrients
  • Minerals including phosphorus, potash (often from granite dust, greensand or wood ashes), calcium and magnesium 
  • Kelp
  • Worm castings

Many home gardeners also strategically plant nitrogen fixing plants, plants that can convert nitrogen in the air to a form that can be used by plants. Rotating plants such as legumes, which can fix nitrogen, with those that cannot, helps maintain a healthy nitrogen content in the soil.

Sources: BioFert, Canadian Fertilizer Institute, Canadian Fertilizers Limited, Canadian Food Inspection Agency, Canadian Organic Growers, Fertilizer Safety & Security Council, Nature’s Nutrients