chad lee © 2006 university of kentucky 1 wheat fertilizer management presentation by: chad lee,...

Chad Lee © 2006 University of Kentucky 1

Wheat Fertilizer Management

Presentation by: Chad Lee, Grain Crops Extension Specialist

University of Kentucky


Most of the information comes from:

ID-125: A Comprehensive Guide to Wheat Management in Kentucky


Objectives

• N rates• N timing• P and K• Other nutrients?


Three Critical Management Issues

1. Seeding: Date, Depth, Rate2. N Rate and Timing3. Fusarium Head Blight


N Requirements

• Fall: 20 to 40 lbs of N needed• Late Winter (mid-Feb): 30 to 50 lbs• Spring (Feekes 5, mid-March):

remaining N – total late winter and spring applications

should equal 60 to 100 lbs N/acre


Fall: 20 to 40 lbs N/acre needed

• Stimulates tiller development.• Usually enough residual N from

preceding corn or soybean crop.• Important for late plantings and/or

low stands (< 25 plants/ft2).


Late-Winter: 30 to 50 lbs N/acre

• 30 to 50 lbs N/acre (conventional till).• 40 to 60 lbs N/acre (no-till).• Mid-Feb (about Feekes 3)• N stimulates tillering.• Poor stands need more N.• Adequate stands need less N.


Late-Winter: 30 to 50 lbs N/acre

• Caution• Excessive N can lead to increased

lodging, disease, and damage from late spring freezes.

• Need to scout fields and apply appropriate rate.


Spring (Feekes 5): Remaining N

• Feekes 5: Psuedo-stem strongly erected; just prior to jointing.

• Start of rapid N uptake at this point.• Be sure not to use too much N or

lodging will be likely.


Spring (Feekes 5): Remaining N

• Total late winter and spring applications should equal 60 to 100 lbs N/acre (conventional) and 90 to 120 lbs N/acre (no-till).

• For wheat yield potentials greater than 70 Bu/Acre, total N should be 80 to 100 lbs/A.

• Use 60 to 80 lbs N/A, total, for lower yield potentials.


Single Spring N Application

• Split-application dates will yield 3 bu/acre more than single applications.

• Logistics cause many farmers to choose the single spring application.



• Target Feekes 5 (mid-March).• Rate should be 60 to 90 lbs N/acre

(conventional).• Rate should be 90 to 120 lbs N/acre

(no-till).



• Feb applications should only be made if tiller counts are low.

• Single N applications made in Feb. promote excessive growth and earlier head development.

• Increases the risks for late spring freeze.


Late N Applications

• N applications to N-deficient wheat at or after Feekes 6 (jointing) will result in yield losses.

• N applications after Feekes 9 (flag leaf) will not increase yield but will increase protein concentration in seed.


N Application Methods


N Application Methods

• Liquid N delivery systems and airflow delivery for solid forms are more accurate than spinner systems.

• Drop tubes will reduce N burn from liquid N.

• Flood nozzles delivering water + liquid N (no more than 60 lbs N/acre) can reduce burning.


Phosphorus

• Critical for root development, tillering, early heading, grain fill, early maturity, and resistance to winterkill.

• Wheat takes up 0.67 lbs of P2O5 for each bushel of grain.

• 80% of P2O5 taken up goes to grain.

• Apply in fall before planting.


Potassium

• Helps lower the incidence of some diseases and adds to straw strength, reducing lodging.

• Wheat takes up 2 lbs K2O for each bushel produced.

• 80% of K2O taken up goes to grain.

• Apply in fall before planting; can be applied in the spring if necessary.


Other Nutrients

• Ca, Mg, and S deficiencies have not been observed in Kentucky.

• Micronutrient deficiencies have not been observed in Kentucky.

chad lee © 2006 university of kentucky 1 wheat fertilizer management presentation by: chad lee,...

Documents

lbs of n

chad lee

n feekes

total n

lbs nacre slide

single n applications

residual n

n requirements