Illinois is one of the top national producers of corn, soybeans, and swine, with almost 80% of the state’s land area dedicated to agriculture. The economic and nutritional benefits afforded by agriculture are undeniably important. However, the Illinois Environmental Protection Agency found that pollution from crop production impairs approximately 20% of the state’s streams. Such impairment denies Illinois citizens and wildlife the right to clean, safe water. The most common pollutants from agriculture are sediment, nitrogen, and phosphorus.
Illinois farmland is among the best in the world because it used to be nutrient-rich, wetland prairie habitat. However, unlike prairie, agricultural fields typically contain a protective cover of plants for only about half of the year, and the rest of the time bare soil is exposed to the elements and erodes into rivers and lakes during rainfalls and snowmelt. Even during the growing season, soil loss is greater from agricultural fields than natural land cover. This erosion of land into water results in the sedimentation of our waterways, which means that fish have fewer places to spawn and rivers have less capacity to store water and subsequently flood more often.
Fertilizers applied to agricultural fields contain the nutrients nitrogen and phosphorus. Nutrients are great for crop growth, but a large percent of what is applied eventually winds up in nearby waterways and becomes pollution. Too much nitrogen and phosphorus in water can result in excessive algal growth, which is often aesthetically unpleasing and causes the loss of dissolved oxygen with subsequent stress on aquatic species. Phosphorus gets into our waterways during heavy rains and snowmelt, whereas nitrogen typically enters via the thousands of miles of underground pipes (i.e., tile drains and drainage outlets) that drain Illinois’ agricultural fields.
Important strides have been made in the last 25 years to reduce the amount of agricultural runoff polluting Illinois’ waterways. These reductions have been achieved with a variety of conservation practices and advanced technologies. For example, soil testing and GPS technology allow farmers to precisely apply fertilizer to the areas where it is needed. Conservation practices that effectively keep soil and nutrients on the land include drainage management, wetlands, riparian buffer strips, and spring fertilizer application. Fortunately, USDA’s Natural Resources Conservation Service and Illinois Department of Natural Resources offer a number of cost-share programs that help landowners install these practices and technologies.
In order to protect Illinois’ waterways from polluted agricultural runoff, Prairie Rivers Network is pushing for improved policies to curb runoff, working with agencies and landowners in target watersheds, and asserting, in spite of opposition from strong agribusiness interests, that clean water and agriculture can co-exist as priorities.