taking a closer look at your soil...

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Taking a Closer Look at Your Soil Report

Sarah Kenyon

Agronomy Specialist (417) 967-4545

[email protected]

• Taking a Good Soil Test • Interpreting Your Soil Report • Ag Lime vs. Pelletized Lime • How to buy fertilizer • Non-Traditional Fertilizers • Tips to maximize your dollar

Outline

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Get a Useful Sample • Sample 20 acres

or less • 15 – 20 Cores • 6 Inches Deep • Place in a clean bucket

and mix well • Remove grass, sticks,

and rocks • Place about a pint of

soil in a soil sample box & label

• Discard excess soil

Sampling Tools

• Shovel or spade • Soil probe • Soil auger

Timing of Soil Sampling

• Avoid sampling soon after fertilization, liming, or manure application.

• Best to wait 3 months

• Sample every 2 to 3 years. • Better to do a quality job (more cores per sample) less

frequently

• Sample the same time every year. • Avoid sampling within 150 feet of watering

points, shade trees, gravel roads and other known hot spots 5

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Soil test data from one core is highly variable

020406080

100120140160180200

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61

Core number

Soil

test

P (B

ray-

I, lb

s./ac

re)

Mean: 44 STD: 48

7

Accuracy can be increased by dividing fields based on known variability

020406080

100120140160180200

4 8 11 14 19 22 25 28 31 36 40 45 48 51 54 57 60 63 3 16 38

Core number

Soil

test

P (B

ray-

I, lb

s./ac

re)

Feeding areas Old manure piles

Overall Mean: 44, STD: 48 Pasture mean: 20, STD: 17 Feeding area mean: 114, STD: 52

Pasture

Why test your soil?

• Avoid potential nutrient deficiencies

• Identify possible causes for poor pasture or hay production

• Save money $$$ – Apply enough plant nutrients – Avoid excessive expense

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A. Field info

B. Soil test info

C. Rating

D. Nutrient requirements

E. Cropping options

F. Yield goal

G. Pounds per acre

H. Limestone suggestions

I. Special notes

10

pHs – salt pH

• H+ ions in soil solution • Indicates the level of active soil acidity • Measured in a neutral salt solution • Lower readings but repeatable

– pHs 0.5 units lower than pHw

http://upload.wikimedia.org/wikipedia/commons/b/b2/PH_scale_2.png

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Benefits of proper pH • Increased efficiency of fertilizers

• Reduced availability of Al & Mn

• Favorable microbial activity

• Better soil structure

• Increased longevity of legume stands

• Improved activity of certain herbicides

• Improved availability of soil nutrients

• Effective Neutralizing Material (ENM) • Rates the effectiveness of the limestone

• Grinding limestone finer improves its solubility and speeds up reaction with soil

• Smaller the particle size, the faster the action (higher ENM)

Ag Lime • Lime is the most economical nutrient to apply

Ag Lime

• Effective Neutralizing Material (ENM) – To determine the amount of limestone needed in

tons per acre, divide the ENM value on the soil report by the ENM guaranteed by your ag lime dealer

Ag Lime

• Effective Neutralizing Material (ENM) – To determine the amount of limestone needed in

tons per acre, divide the ENM value on the soil report by the ENM guaranteed by your ag lime dealer

EXAMPLE: If the soil test ENM requirement is 1395 and the lime quarry guarantee is 420 pounds ENM per ton of limestone, then you will need 3.3 tons of limestone per acre (1395 ÷ 420).

Ag Lime

• Limestone is not very water soluble; therefore, it reacts slowly with soil • May take as long as 1 year • Incorporate limestone for more effective use

• Ag lime contains calcium carbonate, which is used to neutralize the pH

• Dolomitic lime also contains magnesium, and is used on magnesium-deficient soils

Pelletized vs. Ag Lime

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$18/a

$110/a

$11/a

Pell-lime 1 ton/a Pell-lime 200 lb/a

Ag-lime 1 ton/a

David Dunn and Gene Stevens – MU Delta Center

Pelletized vs. Ag Lime

• Advertisements claim that 300-400 lbs of pelletized limestone = 1 ton ag lime

• Ag-lime and Pell-lime compared at equivalent effective rates on soil = pH 3.5

• Each product compared at same effective rate, MU recommendation was 1209 ENM/a

• Ag-lime = 2.4 ton/a $43 • Pell-lime =1.7 ton/a $187

18 David Dunn and Gene Stevens – MU Delta Center

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Comparison of Cost and Effective Neutralizing Material (ENM)* of Ag Limestone With Two Sources of Pelleted Lime.

% CCE

lbs ENM/ton

Cost/ton1 Cost/lb of ENM

lbs needed to equal ENM in 1 ton of ag lime

Ag Lime 90 421 $30 7.2¢ ------- Pelleted Lime #1

87 682 $150 22¢ 1235

Pelleted Lime #2

90 491 $150 30.6¢ 1714

*Limestone Quality Calculator http://www.aragriculture.org/forage_pasture/limestone.htm 1 Spreading cost not included

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2.0

2.5

3.0

3.5

4.0

4.5

5.0

0% 25% 50% 75% 100%MU Recommended ENM rate

Soi

l pH

sal

t

Ag LimePell Lime

pH at Harvest for Ag-lime and Pell-lime Treatments applied at equivalent effective rates

David Dunn and Gene Stevens – MU Delta Center

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Theoretical soil pH Adjustment

Lime Rate

Soil

pH

Low

High

Low High

Each soil will have a different lime response due to buffering capacity differences

Low rates of lime on very acid soils do not increase pH out of this range

When enough lime is applied to overcome the soil’s buffering capacity, the soil pH increases rapidly per unit of lime then levels off. Some soils require much more lime to reach this point than others.

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Theoretical soil pH Adjustment

Lime Rate

Soil

pH

Low

High

Low High

Each soil will have a different lime response due to buffering capacity differences

Low rates of lime on very acid soils do not increase pH out of this range

When enough lime is applied to overcome the soil’s buffering capacity, the soil pH increases rapidly per unit of lime then levels off. Some soils require much more lime to reach this point than others.

Soil pH Adjustment

• Soil pH 4.9 ENM Requirement 1390 – West Plains Limestone ENM 400

• 3.5 tons/A – Springfield Limestone ENM 600

• 2.3 tons/A – Pellitized Limestone ENM 900

• 1.5 tons/A

How Much Fertilizer do I Need?

How Much Fertilizer do I Need

• 3 numbers that describe N-P2O5-K2O • A bag of diammonium phosphate will have the

numbers 18-46-0 on it – it contains a minimum of 18% N, 46% P2O5, and

0% K2O by weight • The numbers do not add up to 100 percent,

because fertilizers usually contain filler materials that help granule formation and assist with even product application


Material Analysis N (%) P2O5 (%) K2O (%) S (%) Ammonium Nitrate 33-0-0 33 0 0 Ammonium Sulfate 21-0-0-24 21 0 0 24 Diamonium Phosphate (DAP) 18-46-0 18 46 0 Potassium Chloride (Murate of Potash) 0-0-60 0 0 60 Potassium Sulfate 0-0-50-16 0 0 50 16 Potassium Magnesium Sulfate 0-0-22-22 0 0 22 22

Triple Super Phosphate 0-46-0 0 46 0


• In order to calculate a fertilizer application rate, you will need: 1. N-P2O5-K2O content of the material from the

package label 2. Your target rate (normally from a soil test) 3. The total area you will be applying to 4. The density of the material if a liquid fertilizer is

to be used


• Example: Fertilizing Tall Fescue Hay – Granular ammonium sulfate (21-0-0-24S) – 60 pound N per acre.

• How much fertilizer is needed per acre?

• Answer: 60 lb N/acre ÷ 0.21 = 286 lb ammonium sulfate/acre


• Example: Fertilizing with 19-19-19 – 19-19-19 to tall fescue hay – 100 lb per acre – Soil report calls for 60 lb N per acre

• Is this enough fertilizer to feed the plants?

• Answer: 60 lb N/acre ÷ 0.19 = 315 lb/acre

Useful Websites with Fertilizer Calculators

• University of Georgia – http://aesl.ces.uga.edu/soil/fertcalc/

• University of Kentucky

– http://soils.rs.uky.edu/calculators/mult_fert.asp

http://aesl.ces.uga.edu/soil/fertcalc/

http://aesl.ces.uga.edu/soil/fertcalc/

http://soils.rs.uky.edu/calculators/mult_fert.asp

http://soils.rs.uky.edu/calculators/mult_fert.asp

Useful Apps for Fertilizer Calculations

• Fertilize by Alabama Cooperative Extension

• Fertilize Cost Calculator

• Fertilizer Removal by Crop: by Ag PhD

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Effect of N source on fall growth of tall fescue at three Missouri locations

0

500

1000

1500

2000

2500

3000

DM

Yie

ld (

lbs/

a)

Mt. Vernon 05 Linneus Mt. Vernon 06 Columbia

Location

Am. Nit. Urea Am. Sulf. Urea + Agrotain Control

*

Kallenbach - 2006 N applied August 17 at 75 lbs/A No difference when applied in March

Liquid Fertilizer Units per gallon of Material

N P2O5 K2O

Gallons to equal 50 lb

N

8-0-0-9 (10.1 ) 0.8 0.0 0 62.5

32% (11.1) 3.6 0 0 13.9

28% (10.6) 3.0 0 0 16.7

Source: John Jennings, University of Arkansas Extension

Liquid Fertilizers

Treatment

Ammomium NitrateUAN Urea U+Montys U+S90 U+FE Montys S90 FE

Yie

ld (l

bs D

M/a

cre)

0

1000

2000

3000

4000

5000

6000

7000

8000

Evaluation of nontraditional fertilizers for bermudagrass yield - 2008

AmmoniumNitrate

LiquidUrea

Urea Urea +Monty'sPlt Food

Urea +Sea 90Mineral

Urea +FishEmulsion

Monty'sPlt Food

Sea 90Mineral

FishEmulsion

Total of two harvests (7/28 & 10/17)

A

BBAB

B

C

CC

C

Bars topped by thesame letter are not

different at the 0.05 level

AN, Liq. Urea, & Urea applied at 75 lb/a NMonty's Plt Food - 1.5 pints/aSea 90 Mineral - 2 lbs/aFish Emulsion - 4 gal/a

UntreatedCheck

AB

Treatments applied on 6/27 and 8/5


Nontraditional Fertilizer Trial Nitrogen content and total nitrogen applied

% N lbs N/unit lbs N applied/acre

Treatment

Ammonium Nitrate 34% 680 lbs/ton 75

Urea 46% 920 lbs/ton 75

Liquid Urea 23% 2.5 lbs/gal 75

Monty’s Plant Food 8% 0.9 lbs/gal 0.2

Fish Emulsion 5% 0.6 lbs/gal 2.4

Sea 90 Mineral 0% 0 lbs/ton 0


• Amount nutrient required vs. amount in product • Always ask for DATA! • Beware of testimonials without data

-too much variability in farms, weather, etc. • It’s OK to experiment, but make sure you have

a side-by-side comparison

Evaluating nontraditional fertilizers

Ammonium Nitrate vs. Urea • Ammonium Nitrate

– No volatilization – Increased yield for forages, corn, and wheat – Availability problems b/c of regulatory issues

• Urea – High volatilization rate – Need ½ inch of rainfall – Coating with Agrotain results in high yields

• Use when rain chances are questionable • Use during high temperatures

Tips for Fertilizing on a Budget

1. Take a soil test – You cannot manage what you don’t measure – Helps to determine where to spend your money

2. Lime First

“The poor man’s fertilizer” • For cool-season grass:

– 5.5 to 7.0 • For legumes:

– 6.0 to 7.5 • Limit application to 2 to 3 ton/acre/year • Applying 2 ton/ac every now and then is NOT

a good practice

3. Target Low Testing Soils First

• Soils that test low to very low will respond to increased fertility faster than soils testing medium or better

Yield Response Curve

% Yield

100%

50%

Maximum Yield

95%

H VH

Apply Maintenance

Fertilizer Apply No Fertilizer

Apply Buildup + Maintenance

Fertilizer Economic Optimum

Yield

Detrimental

EX M L VL

Soil Test Level

4. Fertilize at the Right Time

• Phosphorus, Potassium, and Sulfur can be applied anytime during the growing season

• These nutrients are stable when in the soil and are less likely to move off site

• Potassium may need to be applied in split applications because of “luxury consumption” – Bermudagrass – Alfalfa

Fertility Management

• Nitrogen should be applied when the plant has the ability to respond – This nutrient is mobile and has the ability to move

away from the plants root zone

Fertility Management

Nitrogen for Tall Fescue Hay

April August October June

Fora

ge Y

ield

Spring fertilization for Hay: - apply nitrogen in mid March - maximizes natural growth curve

Herd feed requirement

Nitrogen for Tall Fescue Pasture


Fora

ge Y

ield

Spring fertilization for Pasture: - apply nitrogen in early May - extends spring forage into July - less response, higher potential value

Herd feed requirement

Nitrogen for Tall Fescue Pasture


Fora

ge Y

ield

Fall fertilization for Pasture: - apply nitrogen in mid August - increases and extends fall forage - less response, higher potential value

Herd forage demand

5. Add Legumes

• Legumes can add 50 – 200 lb N/year • Need 30% in the stand to have a significant

impact

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Nodulated Plants Produce Nitrogen

• Seeds should be inoculated to ensure fixation

Not inoculated Inoculated

Treatment Yield lb/acre Tall fescue + red clover 11,100

Tall fescue + N 0 lb N/acre 3,900 90 lb N/acre 6,700 180 lb N/acre 9,900

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Yield of Tall Fescue & Clover vs. Tall Fescue & Nitrogen

Source: Taylor Kentucky Agric. Ext. Ser. AGR-26

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Nitrogen Fertilization of Grass/Legume Mixes

0

5

10

15

20

25

30

35

0 25 50 100

% L

espe

deza

Lbs/acre N

6. Manage Other Resources

• Consider how & where you feed hay... – Unrolling, stationary bale rings, move bale rings

• Dragging

Treatment 1 Treatment 2 Treatment 3

Hay Ring in Set Feeding Area

Move Hay Ring Every Other Day

Unroll Hay in a New Spot Daily

40’ X 40’ 20’ X 40’

Stationary Ring

Moving Ring

Unrolling Hay

Move Hay Feeding Sites Often

• Regularly move feeders and feeding areas

• Do not use the same pasture for supplemental feeding every year

Unrolling Hay

• Allows “boss” cows and timid cows to eat together • Less hoof damage to feeding area because it is larger • Distributes fertilizer nutrients back on field

Manures • The good:

– Adds organic matter • Helps improve many aspects of soil health

– Adds micronutrients – Current price = $24 to $35/ton dumped

• The bad: – The smell – Transportation costs – Availability – Nutrient variability

Nutrient Concentration of Manures

Research adapted from Dr. John Lory, University of Missouri

Source Units N P2O5 K2O Poultry Litter lbs/ton 69 82 37 Beef Feedlot lbs/ton 24 23 30 Dairy Slurry lbs/1000 gal 25 25 40 Pig Slurry lbs/1000 gal 58 40 24 Pig Effluent lbs/acre-in 135 102 192

N, P, and K in Poultry Litter

20 to 60% of N can be lost when surface applied

Plants take up phosphate (P2O5), not phosphorus (P) - 80% Available Yr. 1 (100% by Yr.2)

P X 2.27 = P2O5

Plants take up potash (K2O), not potassium (K) - 100% Available Yr. 1

K X 1.2 = K2O

Fertilizer Value

Formula: lbs/ton X availability X price/lb = fertilizer value

Nitrogen 55 X 0.6 X 0.71 = $23.43/ton Phosphate (DAP) 78 X 1.0 X 0.54 = $42.12/ton Potash 55 X 1.0 X 0.55 = $30.25/ton Total value = $95.80/ton

1. Conduct a soil test 2. Lime first 3. Target very low and low testing soils 4. Fertilize at the right time 5. Add legumes 6. Manage manure resources

Fertilizing on a Budget

Consequences of Foregoing Fertilizer

• Reduced forage production • Reduced persistence of desirable species • Excessive weeds and brush • Reduced forage quality • Yield loss

Questions?

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