Look for leftover soil nitrogen
Extension Soil Scientist
Department of Soil Science
UW College of Agricultural and Life Sciences
2:59 – Total time
0:19 – What’s happening in the soil this fall
0:38 – Fate of left over nitrogen
1:06 – What it means for spring planting
1:32 – Take deep soil tests to check
2:17 – Statewide soil N monitoring
2:50 – Lead out
Be aware of leftover nitrogen in the soil profile. We’re visiting today with Carrie Laboski, Department of Soil Science, University of Wisconsin Extension in the College of Agricultural and Life Sciences, Madison, WI and I’m Sevie Kenyon.
Sevie Kenyon: Carrie, start out by telling us what’s going on in that soil profile right now?
Carrie Laboski: In these situations where we have corn that was grown in this past summer and was affected by drought, there’s a high likelihood that some of the nitrogen that was applied to that corn crop is still remaining in the soil profile right now.
Sevie Kenyon: Carrie, what does that mean?
Carrie Laboski: The two fates of this leftover nitrogen are: 1) it can be lost, mainly through the leaching process. If we start getting more rain in the fall and winter and if we do have a drier or about average winter precipitation, and late fall precipitation, a lot of that nitrogen is going to stay in the soil. It will available for a crop next year.
Sevie Kenyon: Carrie, what does that mean to the grower getting ready to plant next spring?
Carrie Laboski: There are fields that have a lot of residual nitrogen, or carryover nitrogen. It means that they can probably apply less nitrogen next spring for their corn crop. This is really only an issue where it’s going to be corn-on-corn. We don’t tend to see a lot of extra nitrogen building up where soybean was the crop for 2012.
Sevie Kenyon: What do you recommending farmers do to monitor this situation?
Carrie Laboski: One of the best things that can be done would be, in the springtime before planting, is to take a pre-plant profile nitrate test. This is not the most exciting test for many folks because the sampling requires that you take sample to two foot deep. So, you take a zero to one foot sample and a one to two foot sample, send it to a lab and have nitrates measured. What that will do is it will give you a strong indication of how much nitrate’s in your profile. Throughout most of Wisconsin, about 50 pounds of nitrogen per acre is considered background or native, in the early springtime, prior to planting.
Sevie Kenyon: Carrie, what are you doing to keep tabs on the situation?
Carrie Laboski: Well, what we’re starting to get set up right now is a soil nitrate-monitoring network. I’m working with our county extension agents, where we’re going to start taking soil samples this fall and then again in the springtime. We’re developing a website so that anybody can go in and look to see what the results are. If you’re living in Columbia County, you can look and see, “Okay, well, hey, there was some samples taken at Arlington, so that’s kind of close to me…” and see what was left in the soil profile there.
Sevie Kenyon: We’ve been visiting with Carrie Laboski, University of Wisconsin Extension in the College of Agricultural and Life Sciences, Madison, WI and I’m Sevie Kenyon.