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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #69326
Title: OXIDATION-REDUCTION AND GROUNDWATER CONTAMINATION IN THE PRAIRIE POTHOLE REGION OF THE NORTHERN GREAT PLAINS

Author
item Olness, Alan
item STARICKA, JAMES - NORTH DAKOTA STATE UNIVER
item Daniel, John

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/18/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The prairie pothole region of the Northern Great Plains, often intensely used for production of wheat (Triticum aestivum L.), maize, (Zea mays L.), amd soybean (Glycine max L.) is characterized by numerous shallow, glacially-derived depressions. These depressions collect surface runoff of snowmelt and rainfall from nearby fields which infiltrates to shallow groundwater as focused recharge. While only 2 to 5% of the total precipitation is recharge to groundwater, depresssionally focused recharge allows point-source recharge about a month earlier during spring thaw. Nitrate levels increase over winter (5-to 20- fold), but spring recharge dilutes these increased concentrations. Relative measures of aeration made with platinum electrodes during the thawed period show that potentials in well-drained portions of the soil profile remain above +400mV throughout most of the crop year. Similar potential measures made in the base of a previously drained pothole were negative and well below the critical aeration potential for denitrification for most of the year. Therefore, it is unlikely that nitrates contained in rainfall-induced surface runoff moves through prairie potholes to groundwater. However, some bound pesticides such as atrazine and alachlor are solubilized under anaerobiosis. Anaerobiosis effectively doubled the amounts of atrazine and alachlor obtained with resin extraction from a wide range of soils. Thus, contamination of prairie potholes with pesticides may contribute to groundwater pollution when both anaerobiosis and leaching occur.