Getting the "Dirt" on Fertilizer

I could be wrong, but I would bet that most Wedge shoppers who garden try to be as careful about what they feed their lawns, flowers and vegetable gardens as they are about what they feed themselves. In order to do that most effectively, it helps to do a little planning and preparation. Just as you would check a recipe to make sure you have the necessary ingredients and the right tools or appliances, you should check your soil to see if you NEED fertilizer to grow your zinnias or zucchini or blue fescue.

You can do this with a soil test. Testing can be done through county extension agencies, laboratories or even home test kits. Home gardeners and farmers alike rely on soil tests to tell them if their soil is deficient in macronutrients (nitrogen, phosphorus and potassium). The test results can tell you if you need fertilizer to replace lost soil nutrients, or to add minerals that are missing, in order to grow healthier plants.

In addition to the "N-P-K" (nitrogen-phosphorus-potassium) fertilizers, which are rather like the megavitamins of the plant food world, there are also "micronutrient" fertilizers, which are intended to supply other minerals that certain plants require. Some of these minerals include boron, copper and zinc.v

The micronutrient fertilizers can be as healthy and customized as an organic juice drink, made to order at the Wedge juice bar, or they can be full of unwanted chemicals like that instant orange drink the astronauts took to the moon.

The only problem is that, unlike that instant orange drink, which was required to list its ingredients, fertilizer labels only tell you the beneficial ingredients - the reason you bought the product in the first place. However, just as pesticide products contain much more than just the active ingredient that kills the target pest or weed, fertilizers can and do sometimes contain many additional ingredients, such as arsenic, lead, mercury and dioxin.

There is no way to tell simply by looking at a fertilizer that it contains heavy metals or dioxins. Fertilizer companies could require their suppliers to run relatively inexpensive tests for total metals content and eliminate those with levels of metals beyond the average levels existing naturally in the environment. (They are already required to prove that their product contains a specific amount of beneficial ingredient.) Washington State requires each fertilizer product to submit total-metal analyses each year when a product is registered with its Department of Agriculture.

Minnesota law currently states that the product label "guarantee plant nutrients other than nitrogen, phosphorus and potassium only if allowed or required by [the Department of Agriculture] commissioner's rule." Currently, the commissioner does not require the label to contain the complete list of ingredients, so farmers and gardeners don't know what else they're getting.

Heavy metals do occur naturally in the environment. For example, some rock phosphate fertilizers are high in cadmium that occurs naturally in the ore that is extracted from the earth. However, many micronutrient fertilizers contain heavy metals and dioxins that come from the "recycling" of hazardous industrial waste. These operations may include aluminum or copper smelting; the manufacture of cement (which may burn hazardous waste as a fuel source); and steel production. For example, one product, Ironite, is mining waste that has been sprayed with acid and urea.

It has been found to contain extremely high levels of arsenic and lead.

So, by now you're probably asking, "What can I do to protect myself and my family from toxic fertilizer?" Here are a few suggestions:

• Use your own homemade compost. This way, you have control over what goes in.
• Ask questions when shopping for fertilizer products at garden centers and nurseries. Staff should be knowledgeable about the products sold. If not, consider shopping elsewhere.
• Contact manufacturers and distributors. Reputable companies will be happy to provide laboratory analyses and other information about where they obtain the ingredients for their products. Ask them to voluntarily provide full disclosure on their product labels, as we work for mandatory labeling requirements.
• Don't use products labeled "sewage sludge" or "biosolids." These products can contain disease-causing germs, as well as heavy metals and chemicals that are not meant to be handled by sewage-treatment systems.
• Use products approved for certified organic crop production. The Organic Materials Review Institute is the non-profit organization that conducts research on materials used in the production, processing and handling of organic agricultural products and creates and distributes lists of what can and cannot be used.

Learn more. Contact:

Organic Materials Review Institute
Email: info@omri.org
www.omri.org

Institute for Agriculture and Trade Policy
Jackie Hunt Christensen or Patty Landres
Phone 612-870-3424
Jchristensen@iatp.org
www.iatp.org/foodandhealth

Minnesota Statute Chapter 18C.211; 2001
www.revisor.leg.state.mn.us/stats/18C/211.html