Nitrogen Application for Winter Crops

Dave: With the recent rains across Oklahoma, a lot of producers are putting seed into the ground and hoping that it grows this year. We have Brian Arnall to talk to us about how the crops look across Oklahoma, Brian what are you finding?
Brian: Well Dave, we looked back to last year and see what we’ve seen with that draft. We have quite a bit of nutrients left in the soil. We look at last year, we had really good grain prices, everything was looking good so everybody fertilized to meet maximum yields for the most part last year, and then unfortunately as we know, they really didn’t get that maximum yield. They cut short. So that in itself leaves a lot of nitrogen left in the soil because there was no way to lose it. It takes rain to lose that nitrogen that was left over, and that’s why we didn’t get the yields, ’cause we didn’t have the rain.

We look back and we have this residual nitrogen level. We’d been looking at soil tests coming back from the soil testing lab, Soil Water Forage Analytical Lab at Oklahoma State. We’ve had about 3,000 soil samples processed under the Winter Wheat Code. Of those 3,000 samples, there’s about 47% that come back with more than 40 pounds of nitrate per acre. That’s pretty high, that’s enough to get any wheat crop from establishment well into January or February if it’s a grain-only wheat crop. If we look at even further down, there’s 77% of those 3,000 samples that had 20 pounds or more, so that’s a large amount of our soil samples that came in that have a nearly adequate amount for establishment of a stand.

We also looked back at the sulfate tests, there was about 170 sulfate samples came in, and of those 170 samples, 88% had over 20 pounds of sulfur in the top 6 inches. That’s more than enough for any winter crop we’re going to grow, whether it’s wheat or canola, that’s enough sulfur. We can basically look back and see that with that draft we’ve had a lot of water movement up from depth. As the water travels up, so does our mobile nutrients, such as nitrate and sulfur, so we’ve moved a lot of our nutrients from deeper soils up to that top surface. In a lot of cases, we have a fair amount of nitrogen sulfur in our top 6 inches.
Dave: OK. Let’s talk about the pre-plant. What should producers be thinking about right now?
Brian: I’d be thinking – if you haven’t already got your wheat in the ground, you still need a pre-plant. A pre-plant is a good option, putting in some 1846-O, a little bit of nitrous and a little bit of phosphorus with the seed. We see a good response, it gives that seed a good boost. However coming into this year with the outlook that we have for the weather, I don’t know if I’d be putting down 100% of my nitrogen right now.

Let’s make sure we have enough to get that crop up, established, doing good, and into January and February where we can top dress, or even in December. That’s going to be about 20 to 40 pounds of nitrogen depending on your situation. Are you going to try to graze it later, or is it going to be a grain only? 30 pounds of nitrogen will get a grain only crop easily into January.
Dave: What are you seeing as far as fertilizer prices?
Brian: Fertilizer prices have been as up to about last week, wholly and relatively steady. Anywhere between the mid-50’s, low-60’s for Urea and Urea Ammonium Nitrate. 46OO and 28OO. Anhydrous is cheaper, it’s in the 40’s to 50 cent range, and that why a lot of people have been putting down Anhydrous. However you’ve got to look at it, just because it’s cheaper, if you don’t need it this year, you’re wasting the money regardless of the cost. I would be very cautious on all of our pre-plant rates right now not knowing what’s going out. Putting all your eggs in one basket now could be a little bit of a risky option.
Dave: OK. Let’s talk enrich strips. This is the year to possibly look at the enrich strip.
Brian: This is the year the enrich strip can make bank. This is going to be a good year for two reasons. One, we have those draft fields. We have a lot of fields out there that have high levels of nitrate. Producers didn’t sample, we only had 3,000 soil samples across the entire state of Oklahoma. That’s 3,000 samples representing 4 million acres. That’s not very many soil samples for that, so there’s a lot of unsampled acres. Those reference strips out there will tell us no matter what whether that crop needs more or less nitrogen, so those fields that had a lot of nitrate, the strips will tell us we don’t need anymore nitrogen, we have enough to get through the entire season and we’re going to make yield.

That wet belt that we hit over the weekend’s rain where we had 3 to 4 inches up that I-35 corridor, if could keep catching a few rains in that region, we could be looking at bumper crops if everybody gets their seeding up. Those enrich strips out there will tell us if we need more to make that optimum yield. We look back year in and year out. Enrich strips will save or make 10 dollars an acre, and we are always maintaining eleven and a half percent protein everywhere we use that greenseeker sensor and enrich strip.
Dave: OK. Well, Brian Arnall thank you very much, and you can find out more information on our website, sunup.okstate.edu.

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