Chris Heidrich, Seed District Sales Manager and Technology Manager
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It’s pretty easy to apply the same rate of fertilizer on every acre of your wheat crop. But as we all know, doing something the easy way doesn’t necessarily mean you will achieve the best results.
The problem with making blanket fertility treatments is that they usually either supply too much or too little of the nutrients needed to optimize yield potential. And either outcome can take a toll at harvest.
Variable-rate technology lets you apply different fertilizer rates to different areas of your wheat fields, which can help you increase input efficiency and improve overall performance. Since most fields on a particular farm are not equal in terms of soil type, productivity and fertility levels, it only makes sense that they would benefit from customized treatments. Additionally, you can help improve sustainability and environmental stewardship on your operation by not over-applying fertilizer.
Start with a soil sample
A great complement to variable-rate fertility is zone-based soil sampling, which can help you achieve higher yield potential and improve the ROI potential of your wheat crop. Soil sampling has been a common practice for a number of years. Historically, a composite field-average sample was taken, with the results indicating the available nutrients in the soil and what nutrients at what rate should be added to achieve a desired yield goal.
With today’s technology advancements and continued farmer adoption of variable-rate application strategies, the more sophisticated techniques of zone- or grid-based soil sampling have become common. These practices help ensure there are no missed opportunities within the management zones of a field to capture more wheat yield or to save on inputs.
When inputs are under-applied, yield can be limited, even in the most productive areas. And using too many inputs in low-producing areas gives the crop more nutrients than it actually needs, which is a waste of input dollars. Both of these situations can result in reduced yield potential and lower profit potential. That’s why it’s essential to differentiate between the higher- and lower-producing areas within your fields. I recommend using zone-based soil sampling to identify exactly what nutrients your wheat crop needs.
Depending on your geography, zone soil sampling can be more cost-effective than grid sampling. While both options are effective, grid sampling may require many more samples and much more time, resulting in a higher cost. Zone soil sampling will cost less, and it will still give you valuable information about nutrient variability in the field.
Technology tools can be used to identify your field management zones for zone soil sampling. Work with your agronomist to decide the optimal soil sampling method and number of zones to test for your operation. When soil testing is complete, you can then use the additional layer of information gained from the zone samples to help make your variable-rate prescription plans and input decisions more effective.
Monitor protein levels with zone-based tissue sampling
When we harvest spring wheat, our best-looking, highest-yielding fields often lack protein. Great yields with low protein one year can lead to poor yields and high protein the next year. Many times protein levels are affected by in-season conditions. A dry, hot growing season puts added stress on the crop and usually results in higher-than-normal protein. A wet growing season usually results in lower protein and potentially more disease.
Because we don’t know what kind of growing season to anticipate, managing fertility in high-protein wheat can be challenging. Fertility levels can have a big effect on wheat protein levels, so you should make sure your wheat crop has the right amount of nutrients in the field, based on the anticipated number of bushels it will produce.
A mid-season fertilizer side application is a common way to increase protein quality. In-season satellite imagery along with zone-based tissue sampling can help identify areas of the field that may need more nitrogen to help boost protein.
By generating a variable-rate prescription based on in-season satellite imagery, you can apply fertilizer only where it’s needed to help both increase quality and achieve better yields. Using variable-rate technology can also potentially improve protein levels while optimizing your fertilizer investment, which is good for ROI. In hard red spring wheat, higher protein usually means a higher price.
Each year brings different weather, crop prices and protein premiums. Whatever happens in 2019, keep your options open by maintaining the quality of your spring wheat.
On-farm trial results
In 2015, 2016 and 2017, my colleagues at WinField United and I performed side-by-side variable-rate and static rate checks on farms in western North Dakota and eastern Montana, where variable-rate fertility applications were being performed on wheat for the first time. These were not scientific trials and there was no attempt to replicate the trials. The objective was to give farmers some perspective on how variable-rate fertility applications could potentially impact yield in their fields.
As we compiled yield data from the trials, we found crops that received variable-rate treatments outyielded the static strip by an average of nearly 4 bushels per acre.* Although these trials were performed with spring wheat, I believe the same overall management concept can apply to winter wheat and durum.
Give variable-rate fertility a try
At this point, most of the customers I’ve worked with to set up variable-rate technology applications on their farms have not switched back to making blanket fertility treatments. While dividing your acres into management zones and switching to variable-rate fertility applications takes some extra work up front, I’m confident you’ll see some benefits on your fields. Talk with your agronomist or your local WinField United retailer about how variable-rate fertility applications can help you get greater yield potential and higher quality from your wheat, save on input costs, and make your operation more sustainable.
* Source: 2015–2017 customer field trials (52 locations in Montana and North Dakota). Because of factors outside of WinField United’s control, such as weather, applicator factors, etc., results to be obtained, including but not limited to yields, financial performance, or profits, cannot be predicted or guaranteed by WinField United. Actual results may vary.
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Publish Date
December 2018
