While many eastern areas of the Dakotas and Manitoba had good yields, the western areas suffered with dry conditions. In areas with good crop yields, the soil nitrate levels were very similar to 2007 (see figures below). In areas where dry conditions continued for the second or third year, crop yields were poor and soil nitrate levels are much higher on average than 2007.

Two figures show the average soil nitrate level following wheat in 2007 and 2008. The third figure shows the difference between the average soil nitrate level in 2007 and 2008 in each zip code area. At this time of year we usually have compiled the regional figures for the average soil nitrate following corn, but the delayed harvest makes that impossible at the time this article was written.

While it is interesting to look at the big picture to see general differences from year to year, it is very important to soil test each field to determine the level of soil nitrate remaining in the 0-24" soil profile in that field. High fertilizer prices are just one more reason to get a current soil test. Soil testing is not a perfect tool, but it is the best management tool available to help you determine the rate of nutrients needed for next years crop.

Average Soil Nitrate following Wheat in 2008

Soil Nitrate Change from 2007 to 2008

Higher Soil Nitrate in Western Areas Due to Dry Conditions

Average Soil Nitrate following Wheat in 2007