Let’s first take into consideration the nutritional requirements of winter wheat and what your soil can offer.
As with other crops, wheat fertility programs are best determined by a soil test that will assess pH, phosphorus, and potassium needs. A soil test is critical to assessing what capabilities your soil has and what you will need to amend. Without a soil test you may be missing yield opportunities by under fertilizing your crop or over-fertilizing the crop – wasting money, potentially causing issues in your cropping system, and eating up profits.
We can address winter wheat needs with a combination of fall fertility and manure. Nitrogen applications should be based on yield goal and split between fall and spring. Some additional considerations for fall fertility:
- Maintain an optimum pH between 6.0 and 7.0 to limit winterkill and maximize nutrient availability.
- Nutrient removal for wheat approximately is 0.7 lbs of P2O5 and 2 lbs of K2O for each bushel produced. This assumes the straw is removed. Apply phosphorus and potassium fertilizer in the fall, prior to planting for best results. Ideally, all of the phosphorus and potassium may be broadcast prior to planting, but if soil test levels are near optimum then delaying until after harvest would be an option to replace removed nutrients. Harvesting straw can deplete potassium levels quickly if this is not considered and may result in a potassium deficiency in subsequent crops. Straw nutrient removal for a two-ton crop is on average 8 lbs P2O5 and 46 lbs K2O.
- Having some fall nitrogen availability is critical to promote tillering and maximize yield potential. Often this need can be met by residual soil nitrogen from previous crop residues like soybean, but if the proceeding crop is corn, and the corn yield exceeds expectations, we may want to apply 20-40 lbs of nitrogen in the fall. This application ensures that we have enough availability to promote vigorous fall tiller development.
- Manure can be an economical way to meet phosphorus and potassium needs, and supply nitrogen. Because of the potential for lodging it is very important to take the full credit for manure and residual N from previous applications. Wheat does not require large amounts of N until stem elongation, Feekes GS 6. Therefore, most of the N should be applied in a spring topdress.
To learn more about winter wheat and other small grain management, please join us for our October 29th ‘Small Grains’ webinar in our Grain Crop Production Series . This webinar will cover small grain management from planting to harvest. The cost is $15 for all three webinars (small grains, corn, soybeans), and includes a PDF digital copy of the Agronomy Guide. Pesticide and CCA credits available, pending approval.