Farming is the leading cause of nonpoint source pollution (pollution washed into water supplies by rain) in the state, according to the Missouri Department of Natural Resources. The pollution comes from soil that is washed into the state's waterways, soil that often contains fertilizers and pesticides, which can hurt water supplies and kill aquatic life.
According to the DNR's 2006 Water Quality Report, more than 13,000 miles of stream in Missouri are "impaired," meaning the stream doesn't meet one or more of several criteria, including water quality that doesn't interfere with aquatic life, and nearly 7,500 miles may be impaired. The same report said more than 19,500 lake acres are impaired with 2,000 more suspected.
With increased acres being devoted to corn production, the potential for increased pollution is looming. To combat the problem the DNR will distribute $6.5 million over the next five to seven years to local soil and water conservation districts.
Southeast Missouri is fortunate when it comes to pollution of ground and surface water supplies, said Ken Struemph, environmental manager for DNR's Soil and Water Conservation Program.
But keeping nonpoint source pollution from agriculture from becoming a problem in Southeast Missouri is a priority, Struemph said.
Earlier this month the state Soil and Water Districts Commission announced $6.5 million will be distributed throughout the state to prevent nonpoint source pollution from agriculture under the newest round of special area land treatment, or SALT, programs. The programs will last five to seven years.
Three watersheds in Southeast Missouri -- St. John's Bayou in Scott County, Bess Slough in Stoddard County and Pemiscot Clay Root Bayou in Pemiscot County -- will take part in the projects.
Farmers voluntarily enroll in SALT, a program that pays them to implement practices that reduce erosion and runoff and teaches other farmers about those practices.
These practices primarily involve improving irrigation efficiency by installing new irrigation systems and stopping sediment runoff through practices like planting vegetation.
Nonpoint source pollution can be especially prevalent at farms that require irrigation to grow crops. Farmers, especially those with old, inefficient irrigation systems, might put too much water on crops, causing the excess water to run off into surface waters or leach into the ground. That water might contain nitrogen or phosphates from fertilizers or chemicals from pesticides.
In Stoddard County, where $750,000 will be spent in the 18,007-acre Bess Slough watershed, well over 90 percent of agricultural activity is irrigated row crop farming, said Kurt LeBeau of the Stoddard County Soil and Water Conservation District.
When nitrogen and phosphates enter water supplies, they can spur growth by algae and other organisms that deplete the water's oxygen levels, killing marine life. Pesticides can be poisonous to marine life. Nitrogen or pesticides also can be toxic to humans.
The problem has become exaggerated in recent years, as nitrogen from many sources, one of them being farming, has entered the Mississippi River and eventually the Gulf of Mexico, where in the summer it creates a "dead zone" where marine life can't exist in the coastal waters.
Using fertilizer to increase yields over what the plants can absorb also creates leaching and runoff. The problem is multiplied by corn farming, because corn requires large quantities of nitrogen.
Quantifying the effect agriculture has had on local water supplies can be hard. The DNR keeps a list of impaired water sources, but some are yet to be tested. Testing the amount of harmful substances in the water supplies doesn't always tell those doing the testing where the pollution came from, because nonpoint source pollution can come from a variety of sources, including development and urban areas.
Kay Dover, manager of the Scott County Soil and Water Conservation District, said she doesn't have data on how agriculture is affecting water in the 40,494 acre St. John's Bayou watershed that starts at Benton, Mo., and runs to the southern edge of Sikeston, Mo., where $561,921 will be spent as part of the SALT project starting July 1.
"You really don't know until you've tested the water," Dover said. Some water testing will take place as part of the newest SALT program, she said.
Nor are there any standards on the state level saying what level of nutrients like nitrogen are acceptable for water supplies. A group made up of government personnel and private researchers are working to develop criteria for lakes right now, a process that could take years, before they move on to wetlands and streams.
Struemph said there will always be some nutrient loss from farming, no matter what practices are implemented to control them. "We hope to minimize it as much as we possibly can," Struemph said.
But Struemph is confident progress is being made as more and more farmers learn about management practices. One motivation to implement those practices is the rising price of fertilizer, which makes more efficient use of nutrients good for farmers' wallets and good for water supplies.
335-6611, extension 182