Nitrogen Rate Nitrogen Rate Determination for Winter Determination for Winter

WheatWheatMaximizing the Yield of Maximizing the Yield of

Winter Wheat.Winter Wheat.Dale Cowan Dale Cowan

AgriAgri--Food LaboratoriesFood Laboratories

Winter Wheat Maximizing YieldWinter Wheat Maximizing Yield

Maximizing Yield with seeding rates.Maximizing Yield with seeding rates.Tiller Counts.Tiller Counts.Timing of NitrogenTiming of NitrogenRole of NitrogenRole of NitrogenUniformity of ApplicationUniformity of ApplicationSource of NitrogenSource of NitrogenPotash and N topdressPotash and N topdress

Seeding RatesSeeding Rates

Maximizing yield should have started Maximizing yield should have started last fall at seeding time.last fall at seeding time.We should aim for 20 seeds per foot We should aim for 20 seeds per foot of 7 inch row.of 7 inch row.This will provide a stand of 1.5 This will provide a stand of 1.5 million plants per acre.million plants per acre.Plant by seeds per pound, a variety Plant by seeds per pound, a variety with 12,000 seeds per pound would with 12,000 seeds per pound would require a rate of 125 pounds of seed require a rate of 125 pounds of seed per acre. per acre.

TilleringTillering

With early planting before Oct 10With early planting before Oct 10thth, , the 20 seeds per foot of row would the 20 seeds per foot of row would likely produce 40 to 60 tillers this likely produce 40 to 60 tillers this spring.spring.Later plantings produce less tillering.Later plantings produce less tillering.The number of tillers is an important The number of tillers is an important clue as to the status of the wheat clue as to the status of the wheat crop this spring.crop this spring.The tillering will determine timing The tillering will determine timing and rate of Nitrogenand rate of Nitrogen

Tillering and N RatesTillering and N RatesSome fields and areas within fields may Some fields and areas within fields may have 6 to 8 tillers per planted seed.have 6 to 8 tillers per planted seed.Other fields or areas within the field may Other fields or areas within the field may only have single plants and no tillers.only have single plants and no tillers.The highly tillered areas are indicating a The highly tillered areas are indicating a large supply of Nitrogen already present large supply of Nitrogen already present and will indicate that N applications need and will indicate that N applications need to be delayed and reduced.to be delayed and reduced.Apply 70 pounds of N before Zadocs 31 Apply 70 pounds of N before Zadocs 31 (stem elongation.)(stem elongation.)

Tillering and N RatesTillering and N RatesAreas with few tillers probably from late Areas with few tillers probably from late planting or non uniform emergence will planting or non uniform emergence will need a high rate of N and sooner.need a high rate of N and sooner.Apply 100 to 120 pounds of N as soon as Apply 100 to 120 pounds of N as soon as possible.possible.This high N rate early will be necessary to This high N rate early will be necessary to stimulate spring tillering.stimulate spring tillering.Wheat plants can only support 2 or 3 Wheat plants can only support 2 or 3 tillers any more than that the extra tillers tillers any more than that the extra tillers take away nutrients, light and energy and take away nutrients, light and energy and may decrease yield if N is applied early.may decrease yield if N is applied early.

!st Tiller

Main

2nd Tiller

Zadocs 26 to 29

Kill weeds early before Zadocs 31

Stand loss can occur at any time. Below, this occurred after a late March ice storm. Water and ice accumulated in this depression area for 5 days.

60 lbs N

April 2590 lbs N May 9

Milton Site OSCIA 2003 GHG Mitigation N Plots Winter Wheat

60 N Apr 17

90 N May 9

125 N Apr 25

Milton Site OSCIA 2003 GHG Mitigation N Plots Winter Wheat

Delayed N ApplicationsDelayed N Applications

The advantage of delayed N The advantage of delayed N application on highly tillered field will application on highly tillered field will increase Nitrogen use efficiency.increase Nitrogen use efficiency.Decrease the likely hood of lodging.Decrease the likely hood of lodging.Reduce excessive vegetative growth Reduce excessive vegetative growth and promote a canopy environment and promote a canopy environment less likely to support disease less likely to support disease development.development.

Role of NitrogenRole of Nitrogen

Nitrogen provides 2 basic functions.Nitrogen provides 2 basic functions.It can be used to manipulate the number It can be used to manipulate the number of tillers and number of heads.of tillers and number of heads.Nitrogen provides the necessary nutrition Nitrogen provides the necessary nutrition to form protein.to form protein.Usually most soft winter wheats are Usually most soft winter wheats are destined for the pastry flour market and destined for the pastry flour market and do not require high protein. do not require high protein. Split applications of N are not necessarySplit applications of N are not necessary

Uniformity of ApplicationUniformity of Application

Uniform application of Nitrogen is a Uniform application of Nitrogen is a must.must.Non uniform rates can cause lodging Non uniform rates can cause lodging and misses can cause lost yield.and misses can cause lost yield.Both mishaps can cost you quality Both mishaps can cost you quality and lost marketing revenues.and lost marketing revenues.Yield bus/ acre of Low and High N rates

Low N High N

55 77

Non uniform applications can cost 22 bushel yield lossSource Agronomy Guide Pg 189.

Uniformity of ApplicationUniformity of Application

Rarely do pull type spinner spreaders Rarely do pull type spinner spreaders provide uniform applications.provide uniform applications.Air flow applicators provide greater Air flow applicators provide greater application uniformity.application uniformity.Sprayers equipped with stripper or Sprayers equipped with stripper or streamer nozzles allow application of streamer nozzles allow application of UAN with minimal burn to foliage.UAN with minimal burn to foliage.

Urea and UANUrea and UANUrea and UAN are the 2 main sources of N Urea and UAN are the 2 main sources of N on Wheat.on Wheat.Urea upon application breaksdown into Urea upon application breaksdown into Ammonia and carbon dioxide in the Ammonia and carbon dioxide in the presence of an enzyme called urease.presence of an enzyme called urease.The ammonia is extremely soluble in The ammonia is extremely soluble in water and forms stable ammonium.water and forms stable ammonium.The odds of receiving moisture within 24 The odds of receiving moisture within 24 hours of application in the early spring are hours of application in the early spring are favorable.favorable.It takes 3 to 4 days for ammonia to It takes 3 to 4 days for ammonia to release under cool conditions.release under cool conditions.

UANUANUAN or 28% nitrogen solution is a liquid UAN or 28% nitrogen solution is a liquid formulation of urea and ammonium formulation of urea and ammonium nitrate.nitrate.Surface loss is less with 28% than urea.Surface loss is less with 28% than urea.The use of stripper or streamer nozzles on The use of stripper or streamer nozzles on farm sprayers as given additional farm sprayers as given additional flexibility to the application of Nitrogen.flexibility to the application of Nitrogen.The reduced burn with the strip nozzles The reduced burn with the strip nozzles and smaller tracks made by tractors and smaller tracks made by tractors allows for delayed N applications if allows for delayed N applications if deemed necessary by excessive tiller deemed necessary by excessive tiller counts.counts.

Yield Loss Associated with Foliar Burn from UAN Broadcast Applied with Fan Nozzles

% Leaf Burn% Leaf Burn Yield BPA.Yield BPA.

55 7474

77 7070

1313 6767

2121 6767

2727 6060

Nitrogen CreditsNitrogen Credits

Previous crop management practices must Previous crop management practices must be considered in determining final N rates.be considered in determining final N rates.N credits should be given consideration.N credits should be given consideration.Manure application from the fall should be Manure application from the fall should be gestimated by manure test results and gestimated by manure test results and application timings.application timings.Manure may be better utilized on Spring Manure may be better utilized on Spring Wheat where later release of organic N Wheat where later release of organic N sources may enhance protein levels.sources may enhance protein levels.

Nitrate Soil TestsNitrate Soil Tests

Nitrate soil test has been calibrated for Nitrate soil test has been calibrated for corn at sidedress time.corn at sidedress time.There is no calibration for wheat.There is no calibration for wheat.The sampling window is too early to The sampling window is too early to estimate N release.estimate N release.If the test was taken in March the test If the test was taken in March the test result would have to be above 25 ppm to result would have to be above 25 ppm to be assured of sufficient soil nitrate levels be assured of sufficient soil nitrate levels to reach maximum yield. to reach maximum yield.

Nitrogen and Potash ApplicationsNitrogen and Potash Applications

It has become popular to apply muriate of It has become popular to apply muriate of potash with urea in the spring.potash with urea in the spring.The reasons are to keep pace with K The reasons are to keep pace with K removal, reduce lodging and provide a removal, reduce lodging and provide a source of chloride.source of chloride.Cl has proven useful in controlling root Cl has proven useful in controlling root rots.rots.In Ontario a 1.5 bus advantage has been In Ontario a 1.5 bus advantage has been demonstrated when chloride from potash demonstrated when chloride from potash is used.is used.Muriate of Potash is 47% Cl.Muriate of Potash is 47% Cl.

ChlorideChloride

Wheat is sensitive to low Cl levels.Wheat is sensitive to low Cl levels.Cl is necessary for photosynthesis, Cl is necessary for photosynthesis, maintaining cell turgidity and plant health.maintaining cell turgidity and plant health.In South Dakota they have a calibrated In South Dakota they have a calibrated soil test for Cl.soil test for Cl.When the Cl in the top 2 feet is less than When the Cl in the top 2 feet is less than 30 pounds an application of 10 to 20 30 pounds an application of 10 to 20 pounds of Cl will increase yield by as pounds of Cl will increase yield by as much as 4 bushels 69% of the timemuch as 4 bushels 69% of the time

SummarySummary

Scout your fields and determine overall Scout your fields and determine overall vigor.vigor.Perform tiller counts and plant population.Perform tiller counts and plant population.Tiller counts will determine timing and Tiller counts will determine timing and rates of N.rates of N.Apply Nitrogen uniformly.Apply Nitrogen uniformly.Control weeds and use crop protection Control weeds and use crop protection products when necessary.products when necessary.Protect a good crop.Protect a good crop.