Fertilizers & Pollution

What Is Fertilizer?

• All plants require around 18 different nutrients to grow, but only three of them -- nitrogen, phosphorus and potassium -- are required in large quantities and are often deficient in many soils. Fertilizers contain differing amounts of these three nutrients so you can add them to your soil, giving your plants the best chance to grow green and strong. Fertilizers generally come in a package with three numbers, like 10-10-10 or 24-0-4, which represent the percentage of nitrogen, phosphorus and potassium, respectively, in the mixture.

How Does Fertilizer Pollute?

• Fertilizer pollution is considered a nonpoint source of water pollution, meaning that there is no single point of contamination, but rather a slow and sporadic addition of the pollutant over a wide area. The fertilizer you add to your lawn or garden can get into the water supply in one of two ways: by being carried off the surface of the land by rainfall, or by seeping through the soil and contaminating the ground water beneath the land. Fertilizer can also pollute if it is accidentally dropped onto paved ground, where it is quickly moved into water runoff without even getting a chance to be absorbed by the soil. Fertilizer is not inherently bad, as all plants need these nutrients to survive, but when an area is overfertilized or incorrectly fertilized, that pollution becomes a problem.

The Effects of Fertilizer Pollution

• The major issue with fertilizer pollution is a process called eutrophication, where the surface of a body of water becomes nutrient rich, causing an algal bloom. When the algae start to die off, the organic material in the water will reduce the available oxygen in the water, causing many other organisms to die off. Eutrophication is a natural process for warm, shallow lakes, but the addition of fertilizer pollutants can make the process occur over a series of decades, as opposed to centuries. Fertilizer pollution can even harm larger bodies of water, like the Gulf of Mexico. The northern Gulf of Mexico has a dead zone, where oxygen in the water is not sufficient for most forms of life, starting at the mouth of the Mississippi, where surface water pollutants from half the country wind up, and spread over about 6,000 square miles of water.

Ways to Prevent Fertilizer Pollution

• The most important step you can do to prevent fertilizer pollution is to have your soil tested before applying fertilizer. Most states will have a lab, often through a nearby university, where you can send your soil, and for a few dollars, you will learn which nutrients your land needs and which you can skip. You can also choose to use organic fertilizers, whose nutrients leech into the ground more slowly than normal fertilizers. Finally, never apply fertilizer along stream or lake beds, never apply it on frozen ground, and never apply it just before a rain storm.