1. Micronutrient Deficiencies in Wheat
Kurt Steinke, Ph.D.
Soil Fertility & Nutrient Mgmt.
Dept. of Plant, Soil, and Microbial Sciences
Michigan State University

2. General Comments on Micronutrients
Micronutrients defined as:
Nutrients required by a plant for growth
Amount needed is very small (<100 mg/kg) compared to macronutrients (primary & secondary)
Deficiency can be just as yield limiting as a deficiency of a macronutrient
K. Steinke, MSU

3. The Eight Micronutrients
Boron (B)
Chloride (Cl)
Copper (Cu)
Iron (Fe)
Manganese (Mn)
Molybdenum (Mo)
Nickel (Ni)
Zinc (Zn)
K. Steinke, MSU

4. Micronutrient Use is Increasing Because of:
Higher crop yields
Widespread use of N-P-K fertilizers
Higher analysis fertilizers containing less micronutrients
Sales gimmick ($$)
K. Steinke, MSU

5. Micronutrients ARE NOT miracle workers nor magic pills in a bottle
K. Steinke, MSU

6. Soil pH Has the Greatest Impact on Nutrient Use Efficiency
extreme strong slight
acidity acidity acidity slight alkalinity strong alkalinity
nitrogen
phosphorus
potassium
sulfur
calcium
magnesium
iron
manganese
boron
copper and zinc
molybdenum
K. Steinke, MSU

7. Micronutrients - Mn Healthy leaves: 40 – 100 ppm Mn (40-60 target)
Conc. decreases as season progresses
< 20 ppm: deficient
Immobile in plant
Young leaves affected (shadow effect)
Interveinal chlorosis (many field crops)
Wheat: Yellow, dis-colored, colorless spots (Similar to disease)
Causes: high soil pH (>6.5), imbalance with other nutrients (Ca, Mg, Fe, Zn)
For every 1 pH unit ↑, 100x decrease in soil [Mn2+]

8. K. Steinke, MSU

9. Micronutrients - Mn Corrective Measures
Most effective as starter applications
Soil or foliar
Soil banded: 4 – 18 lbs Mn/A (Mn sulfate)
Soil b-cast: >20 lbs Mn/A (not recommended)
Mn oxides and chelates not effective for soil application
Foliar: lb Mn/A in 30 gal H2O
Mn sulfate or chelates work best
Do not apply to chelate to soil as other cations (e.g., Ca or Fe) often replace Mn in the chelate and convert to unavailable forms

10. Micronutrients - Cu Healthy leaves: 8 – 50 ppm Cu (target 8-20 ppm)
Conc. often increases as season progresses (incr root area)
< 6 ppm: deficient
Immobile in plant
Young leaves affected (shadow effect)
Wilting, lack or turgor, bluish-green tip
Often confused with disease symptoms
Grain loses pigmentation
Eventually chlorotic leaf tips and death (may be confused with cold damage)
Causes: Peaty/muck soils, imbalance with other nutrients (Zn, P, Fe
Rare on most Michigan mineral soils
Where present: acid soils, heavily cropped with N, P, and K

11. Yellow, stunted necrosis along edges
K. Steinke, MSU

12. Micronutrients - Cu Corrective Measures Soil or foliar
Soil: 1 – 20 lbs Cu/A based on soil test (Cu sulfate or oxide)
Muck/Peat: lb/A for low or high responsive crop
Chelates not effective for soil application
Foliar: 0.5 – 1.0 lb Cu/A in 30 gal H2O
Cu sulfate or chelates work best
Do not apply chelate to soil as other cations (e.g., Ca or Fe) often replace Cu in the chelate and convert to unavailable forms
Beware: Cu doesn’t leach; If apply too much, toxicity problems are difficult to correct

13. 116
101
K. Steinke, MSU

14. Wheat – Whole Plant – GS 5
K. Steinke, MSU

15. Wheat – Flag Leaf – GS 9
K. Steinke, MSU

16. Take Home Points Tissue Deficiencies Some is good, more is not better
Something will be deficient at some point in the season
Does NOT equate to yield-limiting factor
Collect BOTH soil and plant tissue
Collect from good AND poor areas
Good area = reference point
Transitional area may be sampled to determine why issue occurred
Some is good, more is not better
Beware of large bulk nutrient application
Cation/anion interference
Ex. : High Ca interfering with Mn
Are you creating your own problem?

17. Thank You for the Support!
K. Steinke, MSU