Determining Summer Fertility Needs for Winter Wheat & Canola

Determining Summer Fertility Needs for Winter Wheat & Canola
Eric Hanson
Lindsborg, KS
Late summer is the time frame to make the important pre-plant fertility applications that will help winter wheat and winter canola emerge evenly and build strong root systems before going into dormancy. Here are some things to consider when preparing to make these fertility treatments.
Winter Wheat
Nitrogen (N) is obviously a vital nutrient for winter wheat. The crop’s greatest need for N comes in the spring when the plant is building yield, but it’s still important to supply enough N in the fall to foster early growth for cover to compete against weeds. For that reason I recommend making a split application, providing some N at pre-plant and the remainder as a top dress application during dormancy or in the spring.
Deciding how much N to supply your winter wheat crop is based on a number of variables including variety selection, whether or not cattle are grazing and your overall management strategy. That’s why the best way to determine your N rate is to work with your local agronomist. Doing so will allow you to make variable rate applications to help you optimize yield potential on the high-performing areas of your fields.
Phosphorus (P), potassium (K) and zinc (Zn) are important nutrients to apply before or during planting in the fall. While they can be applied broadcast pre-plant, an in-furrow application is often more effective.
WinField® United offers two quality granular zinc lignosulfonate products designed for in-furrow applications – Zinc 10% LS and Organics Zinc 10% LS. Look to the results of your soil tests to determine application rates.
Winter Canola
Winter canola producers should broadcast N, P and K prior to seeding. Normally you shouldn’t apply more than 1/3 of your N before dormancy because excess N can reduce winter hardiness.
Although sulfur (S) can be made in a split application with N, it’s most commonly applied during winter dormancy. Applying 20 to 30 lbs of S should be sufficient, depending on soil test results. Ammonium sulfate ((NH4)2SO4) is the preferred source for this vital nutrient because elemental forms take longer to break down in the soil, leaving a question as to how much will be available and whether the amount available will meet the plant’s needs.
Boron (B) is another important element in canola. Applying B in the fall can help reduce stress and help improve winter survival. However, B can become toxic to certain crops at excessive rates, so good soil and tissue samples are the best indicators of a B requirement.
Fertilizer Enhancers and Nitrogen Stabilizers
Fertilizer enhancement products increase the fertilizer’s nutrient availability in the plant-available form, while reducing the amount of nutrient tie-up/loss from environmental and soil factors. The following products might work well for your operation, but I strongly encourage speaking with your locally owned and operated WinField® United retailer for customized assistance to determine if they’re a fit for your acres.
  • Avail® Phosphorus Fertilizer Enhancer keeps P in a plant available form, so if you have fields that have high or low pH problems and P availability is an issue, they can be a great fit for the product.
  • Agrotain® Advanced Nitrogen Stabilizer has NBPT as its active ingredient, which works by inhibiting the urease enzyme. It can be a great fit when N fertilizers such as urea or UAN are surface-applied and not incorporated, when volatilization losses are high.
  • N-Serve® 24 and Instinct® HL nitrogen stabilizers have the same active ingredient, nitrapyrin, which inhibits nitrification (the conversion of ammonium nitrogen to nitrate). These are great products when N fertilizers such as anhydrous ammonia, urea or UAN are being applied and will be incorporated into the soil.
Final words of advice
Be wary of sales claims where products are used to eliminate fertilizer use. The best thing we can do is fertilize our crops each season to optimize yield potential and profitability. Unfortunately, there are no magic products that will eliminate the need for fertilizer every growing season. Don’t forget about your micronutrients either; they are just as important as your macronutrients.
Performing NutriSolutions® tissue analysis on winter crops in the spring after green up can help you in two ways. Obviously the first is that it identifies nutrient deficiencies and recommends corrective in-season treatments to help you optimize yield potential of the current crop. The other is that it helps provide insight into how you can improve next year’s late summer/fall fertility program. By keeping the tissue results on file and referring to them again post harvest, you can tweak fall fertility application rates to help prevent nutrient deficiencies and optimize crop inputs and yield potential going forward.
© 2020 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices, and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years, and be mindful of how such agronomic conditions could impact results. NutriSolutions®, Tool and WinField® are trademarks of WinField United. Agrotain® is a trademark of Koch Agronomic Services, LLC. Avail® is a trademark of Verdesian Life Sciences. N-Serve® and Instinct® are trademarks of Corteva Agriscience.

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