MSU Nitrogen recommendations for wheat in 2009
Evaluate wheat at green up to determine damage over the winter and yield potential. Farmers can hedge on nitrogen amounts by using a split application; apply 40 lb N per acre now and then make a second application prior to stem elongation (Feekes stage 6) if the crop condition and yield potential justifies doing so.
Up to 40 lb N per acre can be applied to wheat with a herbicide spray using UAN 28, which is generally more expensive than urea, but will save an extra trip across the field. Dilute the UAN with an equal portion of water and avoid using a surfactant in the spray mix. This will minimize leaf burn.
The total amount of N to apply should
be based on the yield potential of the soil and crop condition. If the N
price is 42 cents per pound and the projected wheat price is $4.60 per
bushel, it will take 0.9 bushels of wheat to pay for each 10 pounds of
N applied per acre. The first 40 to 60 lb N per acre in the spring
application gives the biggest yield response. Four years of wheat
nitrogen rate research at MSU has shown that topdressing 90 pounds of N
only generated 1 to 3 bushels of yield increase for the extra 30 lbs
of N per acre. With current prices and assuming 20-25 lb N per acre was
applied in the fall, a formula for spring N application is (1.15 x
Yield Potential) - 33. Applying this recommended amount of N will
generally produce the best economic return if the yield potential is
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