Post on 16-Oct-2019
transcript
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Taking a Closer Look at Your Soil Report
Sarah Kenyon
Agronomy Specialist (417) 967-4545
kenyons@missouri.edu
• 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
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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
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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
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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
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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.
1
2
1
2
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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
How Much Fertilizer do I Need
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
How Much Fertilizer do I Need
• 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
How Much Fertilizer do I Need
• 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
How Much Fertilizer do I Need
• 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
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
Source: John Jennings, University of Arkansas Extension
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
Source: John Jennings, University of Arkansas Extension
• 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
April August October June
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
April August October June
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
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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?