Some growers with very wet fields have seen higher than expected nitrogen levels in their soil test results. This was a surprise because they expected soil nitrogen to be a lot lower since denitrification and leaching tend to be higher with high moisture. A number of factors could have created an inaccurate result. For example, if wet soil samples warm up quickly in the truck cab or house, the warmth can accelerate soil microbes and increase mineralization, creating a false high result. If growers reduce nitrogen fertilizer rates in response to these results, the field may not have the nutrient it needs to match the high yield potential in these moist soils.
Any time you get an unexpected soil test result, it would be worth doing the test again. When taking the new soil test, make sure to avoid the fertilizer band if applications have already been made in the field.
Growers will not want to hold up seeding while waiting for soil test results, but if new test results are lower than the first results, growers could apply an in-crop top up.
Top up also works if growers can’t get timely delivery of all the fertilizer they need. With so many growers seeding hard at the same time, some fertilizer dealers are having trouble keeping up with demand. Growers may opt to go with what they have for now and then top up later.