Soil pollution occurs when a chemical is introduced into the soil in higher than normal quantities or that normally doesn't occur at all. Soil pollution may result in water pollution through runoff or the leaching of contaminants into groundwater. It may also lead to air pollution when toxins are released into the air. Gardeners should take precautions and use chemical products wisely so that pest control and fertilisation programs don't lead to pollution.
Test Your Soil
Before beginning any fertilisation program, determine what your garden needs by having your soil tested. Different soils require different nutrients and applying chemicals in excess of what is needed may not only harm your plants but pollute the soil. Your local agricultural extension office can test your soil for you and provide recommendations about what fertilisers to use.
Follow the Label
Addressing the Alabama Cooperative Extension, Dr. Charles Mitchell points to homeowners and gardeners as one of the worst abusers of chemical fertilisers. Many hold the misconception that if a little bit of fertiliser will help their lawn or garden, then extra should improve it even further. This isn't the case, however. Excessive use of fertiliser pollutes the soil, where it leaches into groundwater and runs off into lakes and streams. In the Gulf of Mexico, an aquatic dead zone the size of New Jersey can be attributed to fertiliser runoff into the Mississippi River. Always read the label before applying any fertiliser products and follow the directions precisely to avoid contamination of the soil.
In a study done by the University of Minnesota's Limnological Research Center, researchers found that grass clippings and fallen leaves left in the street contributed significantly to phosphorus pollution. Plant leaves naturally contain phosphorus that they extract from the soil, but when they fall on hard surfaces, they cannot be reabsorbed and run off, polluting the soil and groundwater wherever they end up. Keeping your lawn clippings and leaves out of street gutters minimises this source of pollution.
Organic gardening seeks to replicate natural processes that promote healthy plants and soils and considers the impact of a gardening decision on the whole system, not just the plant or garden in question. For this reason, organic methods--such as composting, crop rotation or planting a cover crop--tend to pollute soils less. However, even when using organic fertilisers, take care to apply in accordance with your soil's needs and follow the directions on the label. As reported in "Science Daily," overuse and misuse of organic fertilisers pollutes soils just like chemical fertilisers and with the same disastrous results.