Micronutrient Deficiencies in Wheat - PowerPoint Presentation

Slide1

Micronutrient Deficiencies in Wheat

Kurt Steinke, Ph.D.Soil Fertility & Nutrient Mgmt. Dept. of Plant, Soil, and Microbial SciencesMichigan State UniversitySlide2

General Comments on Micronutrients

Micronutrients defined as:Nutrients required by a plant for growthAmount 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, MSUSlide3

The Eight Micronutrients

Boron (B)

Chloride (

Cl

)Copper (Cu)Iron (Fe)Manganese (Mn)

Molybdenum (Mo)Nickel (Ni)Zinc (Zn)K. Steinke, MSUSlide4

Micronutrient Use is Increasing Because of:

Higher crop yieldsWidespread use of N-P-K fertilizersHigher analysis fertilizers containing less micronutrientsSales gimmick ($$)

K. Steinke, MSUSlide5

Soil pH Has the Greatest Impact on Nutrient Use Efficiency

4.0 4.5 5.0 5.5 6.0 6.5 7.0 7

.

5 8.0 8.5 9.0 9.5 10.0

extreme strong slight acidity acidity acidity slight alkalinity strong alkalinity

nitrogen

phosphorus

potassium

sulfur

calcium

magnesium

iron

molybdenum

manganese

copper and zinc

boron

K. Steinke, MSUSlide6

Micronutrients - Mn

Healthy leaves: 40 – 100 ppm Mn (40-60 target)Conc. decreases as season progresses< 20 ppm: deficientImmobile in plantYoung 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+] K. Steinke, MSUSlide7

K. Steinke, MSUSlide8

Micronutrients - MnCorrective Measures

Most effective as starter applicationsSoil or foliarSoil 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: 1-2.5 lb Mn/A in 30 gal H2OMn sulfate or chelates work bestDo not apply to chelate to soil as other cations (e.g., Ca or Fe) often replace Mn in the chelate and convert to unavailable formsK. Steinke, MSUSlide9

Micronutrients - Cu

Healthy leaves: 8 – 50 ppm Cu (target 8-20 ppm) Conc. often increases as season progresses (incr root area)< 6 ppm: deficientImmobile in plantYoung leaves affected (shadow effect)

Wilting, lack or turgor, bluish-green tipOften confused with disease symptoms

Grain loses pigmentationEventually chlorotic leaf tips and death (may be confused with cold damage)

Causes: Peaty/muck soils, imbalance with other nutrients (Zn, P, FeRare on most Michigan mineral soilsWhere present: acid soils, heavily cropped with N, P, and KK. Steinke, MSUSlide10

Yellow, stunted necrosis along edges

K. Steinke, MSUSlide11

Micronutrients - CuCorrective Measures

Soil or foliarSoil: 1 – 20 lbs Cu/A based on soil test (Cu sulfate or oxide)Muck/Peat: 20-40 lb/A for low or high responsive crop

Chelates not effective for soil applicationFoliar: 0.5 – 1.0

lb Cu/A in 30 gal H2

OCu sulfate or chelates work bestDo not apply chelate to soil as other cations (e.g., Ca or Fe) often replace Cu in the chelate and convert to unavailable formsBeware: Cu doesn’t leach; If apply too much, toxicity problems are difficult to correctK. Steinke, MSUSlide12

Take Home Points

Tissue DeficienciesSomething will be deficient at some point in the seasonDoes NOT equate to yield-limiting factorCollect BOTH soil and plant tissueCollect from good AND poor areasGood area = reference pointTransitional area may be sampled to determine why issue occurredSome is good, more is

not betterBeware of large bulk nutrient application Cation/anion interference

Ex. : High Ca interfering with Mn

Are you creating your own problem?K. Steinke, MSUSlide13

Thank You for the Support!

K. Steinke, MSU