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 Stafford County is out of dry conditions while north of US 50 is abnormally dry. The six to ten day forecast (July 21 to July 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 fourteen-day forecast indicates (July 23 to 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 linked 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鈥檚 briefly discuss how this happens, what favors this problem and some precautionary measures.
路 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鈥檛 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.
路 Point source pollution is much easier to address. Don鈥檛 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?
路 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 is likely to occur, especially for nitrogen fertilizers such as urea and UAN solutions.
路 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 labelled for use, especially with shallow groundwater.
路 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.