Split-applying N: When could it be an advantage?

Transcript:

Linder Farm Network:

It’s time for the AFREC Spotlight, the Agricultural Fertilizer Research and Education Council with Jeff Vetsch, University of Minnesota researcher and soil scientist. Jeff, what are some of the advantages in Minnesota for split applications of nitrogen?

Jeff Vetsch:

I think there’s places where it’s a good insurance policy. There’s places where it’s more likely to give you a return on investment. There’s data that suggests that, well, maybe it’s not as great as we’ve hyping it to be. But in a long term study that I’ve initiated in 2015 in Southeast Minnesota, from the period from 2015 through 2021, only about 20% of the sites had a yield advantage with split application compared to applying all the nitrogen at pre plant and that was at the same total nitrogen rate. But in the last three years of that study, 2022 through ’24, that advantage went to about 25% with split application, plus four of the 12 sites or about one third of them actually needed less nitrogen with split application than with and applied all at pre plant.

Now, 2024 was a very wet year and that was one year that split application did look good. When people ask, you know, what’s the soil conditions? What aside from the climate, what are the factors that are most likely to be advantageous where split application will not only give you maybe a better chance for better yields, but better return on investment. I would say poorly drained soils, especially fields maybe that have tile, but it’s not quite adequate for the amount of rainfall during the growing season we get these days compared to maybe fifty years ago. A study done by the Climate Network in Wisconsin and Minnesota found that over the last seventy five years we get 25% more growing season precip or spring precip now in the southern three tiers of counties of Minnesota.

So that’s pretty significant and I think that that’s what’s driving some of these changes in nitrogen management. However, a study that was done across the Midwest here about eight or ten years ago found that out of those sites were looked at, really only the coarse textured sites really, sandy soils really benefited from split application, which we’ve kind of known for a long time. So there is a little bit of inconsistency in the data, but I think if you have very poorly drained soils, certainly if you have some fields that have coarse textured soils, split application should be something you’re thinking of.

Linder Farm Network:

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