Plant Nutrient Utilization - Cornell University

Crop Nutrient

Utilization Bill Verbeten

NWNY Dairy, Livestock, &

Field Crops Team

Crop Removal of Nutrients

Bill Verbeten Cornell Cooperative Extension

Source: Reference Sufficiency Ranges for Plant Analysis

in the Southern US

Crop Nutrient Utilization

Soil & Tissue Sampling

Crop Nutrient Uptake

Deficiency Symptoms


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Deficiency Symptoms


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Methods-Soil Sampling

2-3 samples per acre up to 10 acres

Sample in a zig-zag pattern


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extension.umn.edu

Methods-Soil Sampling Can sample anytime of year, but be

consistent—most are done in the fall

Use a probe and clean plastic bucket

Mix samples before submitting


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extension.iastate.edu

Soil Sampling Timing

pH varies throughout the year


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From:

Managing Seasonal Fluctuations

of Soil Tests,

University of Kentucky

Cooperative Extension


P varies throughout the year


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From:


of Soil Tests,




K varies throughout the year


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From:


of Soil Tests,




No-till fields sample at 0-1 inch and 0-6

inches

pH stratification on the surface and lower

layers affects herbicides and nutrient

availability


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Avoid sampling in…

Manure/lime piles

Old fence & tree lines

Dead & back furrows

Head lands

Low, wet spots

Fertilizer bands


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hawkhillfarm.blogspot.com

farmprogrsess.com

Tissue Sampling Timing

More samples taken than soil samples to account for variability, usually 30+ plants/field

Sample from “good” and “bad” areas separately

Samples need to be air-dried in a paper bag prior to shipping


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Tissue Sampling Timing

Needs to be at proper plant growth stage

May be too late to correct if sampled at a

later growth stage.

Soil sampling is often done at the same

time for comparison


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Methods-Tissue Sampling

In-season

Small grains

Alfalfa/Grasses

Corn

Soybean

Post-Season

Corn stalk nitrogen test


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Methods-Tissue Sampling Small Grains

Sample 25-35 areas of field

Prior to Stem Elongation All the above ground tissue 50‐75 plants

Prior to Heading Top 4 leaf blades with leaf collar visible 30‐40 plants


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Small Grains

Response common for N, S, Mg, Cu, & Zn


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Alfalfa

Sample top 6 inches just prior to first harvest

Grasses

Sampling the same as alfalfa

Sample at least 30 plants per field


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Alfalfa

Responses to K, S,

& B common

Tissue S 0.25% DM

Tissue K ~2.00% DM

Tissue B 20-80 ppm


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From: Cornell Sulfur Tests For Alfalfa, Cornell Fact Sheet 66

Crop Removal of Nutrients

Sufficiency ranges in grasses N & S often needed

Grasses

Bill Verbeten Cornell Cooperative Extension Source: Reference Sufficiency Ranges for Plant Analysis

in the Southern US


Corn

In-season responses to N, S, & Zn

documented

Often applied as AMS, ZnSO4, or ZnO


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From: Iowa State University Extension


Soybean

If < 12 inches, sample whole plant 1 inch above soil

If > 12 inches, sample top trifoliate leaves, separate from petiole (picture)

Sample at least 25 plants


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From: Sampling Plant Tissue and Soil

for Analysis, extension.missouri.edu


Soybean

Some responses to K, S & Mn documented


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Corn stalk nitrate


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From: Cornstalk testing to evaluate nitrogen

management


Corn stalk nitrate

Collect 1 week

prior to 4 days after

harvest

Ship samples within

a day of sampling


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From: Corn Stalk Nitrate Test , Cornell Fact Sheet 31

Corn Stalk Nitrate


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From:

Cornstalk testing to evaluate

nitrogen management




Deficiency Symptoms


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Mechanisms

Nutrient Forms & Fertilizers


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Crop Uptake happens by…

Root Inception

Mass Flow

Diffusion


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Root Inception

Roots “run into” nutrients

Direct ion exchange at

soil surface

A little bit of most nutrients are taken up

this way


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NO3- NO3-

HPO4-2 H2PO4-

K+ K+

SO4-2

Ca2+ Mg2+ Fe2+

Zn2+

Cu2+ Mn2+ H3BO3

Cl-

MoO4-2

Mass Flow

Nutrients move with water into the plant

Most nutrient uptake happens this way


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NO3- NO3-

HPO4-2 H2PO4-

K+ K+

SO4-2

Ca2+ Mg2+ Fe2+

Zn2+

Cu2+ Mn2+ H3BO3

Cl-

MoO4-2

H20

Diffusion

Nutrient moves from high to low

concentration

Only matters for P, K, Zn, & Fe


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HPO4-2 H2PO4-

K+

K+

Fe2+ Zn2+

Zn2+ Zn2+

Zn2+ Zn2+

K+ K+

K+

K+ K+

K+ K+

Fe2+

Fe2+ Fe2+

Fe2+

HPO4-2

HPO4-2

HPO4-2

HPO4-2


Mechanisms

Nutrient Forms & Fertilizers


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Nutrient Uptake Forms-N

Crops take up

Mostly Nitrate, NO3 -

Some Ammonium NH4 +


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Nitrogen Cycle


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Image Source: fertilizer101.org

Nitrogen Fertilizers NH4+

Anhydrous NH3

Urea Ammonium Nitrate (UAN)

Ammonium Sulfate (AMS)

Urea

Monoammonium phopshate (MAP)

Diammonium phosphate (DAP)

NO3-

Calcium nitrate

Potassium nitrate

Sodium nitrate


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Nitrogen Fertilizers

NH4+ fertilizers can be…

Lost through NH3 volatilization

Converted to NO3 (nitrification)


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Nitrogen Cycle


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Image Source:

fertilizer101.org

Nitrogen Fertilizers Urea fertilizers

Also lost through NH3 volatilization

And converted to NO3

Same chemical composition as urea from urine


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Stabilizers

Different products prevent different losses

Some don’t work (Nutri-Sphere)

Nothing “stabilizes” manure


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Nitrification Inhibitors

N-Serve (Dow AgroSciences) nitrapyrin

Guardian (Conklin) dicyandiamide, DCD


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Urease Inhibitors

Agrotain

(Agrotain International

LLC)

N-butyl thiophosphoric

triamide, NBPT


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Nitrogen Fertilizers Slow release

Microbes break down

protective layer

Sulfur coated urea, ESN,

(Agrium)

Osmocote

(Scotts)

Isobutylidene diurea, IBDU,

(Nu-Gro)


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Nitrogen

Nitrogen Uptake


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From:

plantsci.missouri.edu

Nutrient Forms-P Crops take up

H2PO4- & HPO4-2

Most applied as MAP, DAP, or manure

P from rock phosphate is Only partially available, more in acidic soils

Often contaminated with F and Cd

Treated with strong acids to make fertilizers


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Nutrient Forms-K Crops take up

K+

Potash (KCl) and manure are major sources

Organic farms use KSO4 or sul-po-mag (K2SO4MgSO4)-tend to be expensive $$$$$

Cl- doesn’t harm soil biology, universally present and leaches


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Nutrient Forms-Ca

Crops take up

Ca2+

Supplied by lime, not “fertilized”

No optimal “balance” ratio of Ca in CEC


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Nutrient Forms-Mg Crops take up

Mg2+

Supplied by dolomitic lime, not “fertilized”

No optimal “balance” ratio of Mg in CEC

Grass tetany when low soil/tissue Mg test & high K tests feed MgO or MgSO4


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Nutrient Forms-S Crops take up

SO4 -2

It’s no longer free

Many crops use about 20 lbs/acre/year

AMS (NH4SO4), elemental S, manure, & KSO4 are sources


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Nutrient Forms-B

Crops take up

H3BO3

Small amounts benefit legumes

1 lb/acre/ year on sands

2 lb/acre every 3 years loams and clays

Borate (Na2BO4) and Solubor (Na2BO4)

available as sources


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Nutrient Forms-Zn, Fe, Cu, Mn

Crops take up

Zn2+, Fe2+, Cu2+, Mn2+

Oxides (i.e. ZnO) of these metals are

fertilizer sources


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Deficiency Symptoms


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Deficiency Symptoms

Lower yield

Forage and grain

Stunted growth

Discoloration (pictures)


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Deficiency Symptoms

Micro-nutrient (S, B, Zn, Cu, Mn, Fe,

etc.) deficiencies are most likely…

On sandy or low OM soils

On fields without a history of manure

In drought years (lack of Mass Flow)

Extreme pH soils


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Deficiency Symptoms

Soil Condition B Mn Zn S

Sand X X X

Low OM (<2%) X X X

Dry X

High pH (>6.8) X X

Clay X

High OM

(>6%) X X

Cold X X X

Wet X X


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From: fyi.uwex.edu

Different Visual Symptoms


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From:

www.omafra.gov

For different

nutrient

deficiencies

Nitrogen

Yellowing

Mid-vein & older leaves in corn


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Corn photo from sdstate.edu

Wheat photo from extension.uidaho.com

Grass photo from harrells.com

Phosphorus

Purple edging

Stunted plants


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Barley Corn

Photos from landresources.montana.edu

Photo from extension.purdue.edu

Alfalfa

Potassium

Speckles along leaf margins


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Alfalfa

Photo from extension.purdue.edu

Soybean

Photo from extension.umn.edu

Corn

Wheat

Photo from landresources.montana.edu


Sulfur

General plant yellowing

Stunting


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Photos from landresources.montana.edu

Alfalfa

Wheat

Corn

Boron

Reddening, yellowing, & whitening of

leaves

Usually only deficient in legumes


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Alfalfa

Photos from extension.uidaho.edu

White Clover

Photos from www.aragriculture.org

Zinc

Yellow striping of upper leaves


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Photo from sdstate.edu

Corn

Wheat


Manganese

Yellowing of entire leaf except veins


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Photo from fyi.uwex.edu

Soybean

Questions?


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