January 31, 2018
Wheat Speak: Managing Nutrients In-Season
Wheat Speak with WestBred Wheat is a new audio series bringing you industry leading experts to answer your wheat related questions in a seasonal and timely manner.
As the winter wheat dormancy period comes to an end, growers are questioning what inputs are required to get the most out of their wheat. To find out how to best manage nutrients in-season to increase both the yield and quality potential of wheat, we questioned two wheat experts in the Southern and Central regions. John Fenderson, WestBred® Technical Product Manager for Texas and Oklahoma, and Brian Arnall, Associate Professor of Soil and Food Crop Nutrition and Precision Nutrient Management at Oklahoma State University, shared their tips and answered questions sourced from wheat growers.
Throughout the season, how can wheat growers determine how much nitrogen their wheat will need?
Brian Arnall: Yield goals are a good base level of determining your total nitrogen recommendation. If we’re discussing in-season application, you can look at what you have gotten down as your preplant and subtract that from your yield goal. Of course, if you have any preplant soil test, use that as a guide. One thing we do now at Oklahoma State University that has been very successful is to use the technology of the N-Rich Strip application with a hand-held sensor to get nitrogen rates. Research has shown up in Kansas that the yield goal of a nitrogen recommendation is plus or minus about 25 pounds of nitrogen from the optimum rate.
John Fenderson: One thing that I would recommend to growers is to certainly set a realistic yield goal. They have a history on their farm of yields over time, and they should look at weather patterns to determine this goal. I would also comment that depending on what state you’re in, there are different levels of nitrogen requirements that each state recommends per bushel of production. So, you need to check with your local and state extension soils agent and find out what their recommendation is for pounds of nitrogen per bushel in that state.
Once wheat growers determine their nutrient needs, how can they manage these needs in season?
John Fenderson: If you have got little growth on the wheat as we come into the green-up period in the spring, you may want to think about putting a little more nitrogen out there to try to drive some spring tillering. If you have got adequate tillering, then maybe you can wait a little later in the season to apply that nitrogen closer to the reproductive stage so you can get better utilization out of it. As far as the form of nitrogen you use, the key thing is to get it out there on time and in the right place; make sure that you get it into the soil where the plant can utilize it.
Brian Arnall: John makes some great points with that. One thing about timing is that most of our fertilizers have urea in them that we’re going to be using for top-dress or in-season. If we’re not putting them in the ground, we need to make sure, if possible, to get it on in front of a rain. That really reduces the probability of nitrogen loss through urea volatilization.
When it comes to timing of nitrogen applications, what are your thoughts on split application?
Brian Arnall: The split application of nitrogen is extremely beneficial. Wheat doesn’t use much nitrogen going into winter dormancy, so when we put everything up-front, that provides a great opportunity of loss. The delay of nitrogen, or the split application of nitrogen, allows us to apply it when the wheat crop is really needing it – from the jointing period on.
John Fenderson: It also allows you to make adjustments at that top-dress time and look back over what happened in the winter or the fall. If you had a wet winter or fall, you could increase. If it’s been a poor stand establishment and not enough rain, you can decrease that in-season nitrogen.
If growers are going to choose one time to apply nitrogen during the season, what timing would you recommend as the most beneficial from a yield and protein standpoint?
Brian Arnall: For me, that one timing is as close to hollow stem as we can get. If we’ve got a lot of growth or if we’re needing growth because of late planting, then it will be earlier during spring green-up. But honestly, the closer we can get it on to that time where peak uptake happens, which is right after jointing and in hollow stem, that is the time that the crop needs it the most. That typically translates to the most yield and the most protein.
What are your thoughts on late-season nitrogen application to improve grain protein?
John Fenderson: Late-season application can certainly give us a boost in grain protein and wheat. It’s not 100 percent, though – it’s probably more of a 50/50 proposition. It’s not always going to pay you back in protein, but you do have an opportunity to raise the protein with those late-season applications.
If growers are interested in learning more, where should they go?
John Fenderson: I would recommend that growers contact their local WestBred seed supplier. Otherwise, they can contact their local Regional Commercial Manager or Technical Product Manager or visit us at WestBred.com.
Brian Arnall: Of course, if you’re in Oklahoma, definitely make it to your local county extension office. If you want to see what we’re doing in my program, look at OSU and go to OSUNPK.com.
Wheat Speak with WestBred Wheat is a new print and audio series that connects growers to agronomic experts in the industry to answer their timely wheat questions. Wheat growers can submit questions at WestBred.com/WheatSpeak or find additional episodes at WestBred.com/agronomy.