Many areas of the Great Plains were in the grip of a serious drought this past summer. There were areas that did not receive any measurable rainfall for 60-80 days. The result of this drought was extremely variable crop yields and higher than normal soil nitrate levels this fall in many areas.
Regional trends for soil nitrate levels are one way we can all look at the big picture. The four figures show the average soil nitrate level following wheat and corn production on fields tested in the Dakotas, Minnesota and Manitoba in fall of 2005 and 2006. The bold italicized numbers in the 2006 figures show where the soil nitrate levels are much higher than 2005.
While it is interesting to look at the big picture to see the overall affects of the drought, it is important to soil test each field to determine the level of soil nitrate remaining in the 0-24″ soil profile in that field. Soil testing is not a perfect tool, but it is the only way to determine the rate of nutrients you need to apply to achieve good yields for next year!