By allowing ads to appear on this site, you support the local businesses who, in turn, support great journalism.
Ag and Pollution
Dr. Victor Martin
Dr. Victor Martin

The drought monitor report as of Tuesday, July 14 is basically unchanged from last week. The driest part of the state is still the southwest. Most of Barton County, except the northwest corner, is in moderate drought as is Rice County. The southern half of Stafford County is out of dry conditions while north of U.S. 50 is abnormally dry. The six-to-10-day forecast (July 21-25) indicates a 33 to 40% chance of leaning above normal for temperatures and a 30 to 40% chance of leaning above normal for precipitation. The eight-to-14-day forecast (July 23-29) indicates a 33 to 50% chance of leaning above normal for temperatures and near normal for precipitation.

Recently there have been several reports released regarding groundwater pollution and the link between that pollution and agricultural practices. One focus is on nitrates in ground water while the other is certain pesticides. One pesticide is atrazine, which has an established link to human health. There are other herbicides along with certain insecticides, especially those used as seed treatments. These are established facts. What makes it more challenging is the lack of biological activity, sunlight, and/or temperature to break chemicals down. Today, let’s briefly discuss how this happens, what favors this problem and some precautionary measures.

  • There are two ways for groundwater pollution to occur, point and nonpoint source. Point source, less common in ag caused pollution, is from an easily identifiable single point (source) such as a cracked wellhead, an old abandoned well, or a massive spill. Here, it is much easier to stop the pollution. Nonpoint source is more typical of ag caused groundwater pollution. It isn’t from a single point but say a field or fields. The pollution leaches into the groundwater from a diffuse source which is more challenging to control.
  • Point source pollution is much easier to address. Don’t fill anywhere near a wellhead and make sure it is in good condition. Bulk chemicals and pesticides should have secure containment. Have back siphon devices on filling hoses and so on.

Nonpoint source pollution is another problem taking much more care and knowledge. So, what contributes to it?

  • Depth to groundwater is a major factor. Shallow groundwater, such as south of the river here in Barton County, makes it easier for pollution to contaminate water when there is significant rainfall. This is why for soil applied chemicals, you should avoid applications if at all possible, when significant rainfall is likely to occur, especially for nitrogen fertilizers such as urea and UAN solutions.
  • A second factor is soil texture and organic matter. Sandier soils and those low in organic matter are much more likely to cause movement into groundwater. Pesticide labels contain information regarding rates based on these factors and if the pesticide is even labeled for use, especially with shallow groundwater.
  • While no-tillage has many benefits, a well-developed no-till soil has well connected, deep macropores and something termed preferential flow can occur and move chemicals below the root zone and in some cases, the groundwater.

Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207, or martinv@bartonccc.edu.