Presentation Outline. Soil Sampling. Automation and Precision. Soil Test

Management Units Use field characteristics (soil type, size, history) Using Fertilizer and Soil Amendments by Prescription Improves Farming Practices...
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Management Units Use field characteristics (soil type, size, history)

Using Fertilizer and Soil Amendments by Prescription Improves Farming Practices

websoilsurvey.nrcs.usda.gov

Shelby Filley Regional Livestock & Forage Specialist

Presentation Outline

Soil Sampling

Soil Testing and Reports  Fertilizer Guidelines  Plant nutrients (N-P-K-S…) and pH  Fertilizer materials and lime  Least-cost application  Tracking nutrients and yield 

Collect 15 – 20 subsamples randomly about the management unit. Combine into one composite sample to submit to certified lab.

Soil Test

Automation and Precision

Accurate determination of soil status 2 million lb of soil  Efficient Fertilizer Program 

 

 

Economics Environment

in the top 6" of an acre

Optimizes forage growth Assess property value 

Cost of Improvements

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Sampling Depth





Soil Test Report: Other items

Plow depth

 

Nitrogen (N) and Sulfur (S)



Root zone



6" grass-clover 12" alfalfa

Very mobile in soil & soil test results not used for fertilizer recommendations

Pastures/hay ground OSU fertilizer guide (FG 63)







Variable-depth sampling

40-60 lb/ac N (1–3 times per year) 20 – 30 lb/ac S in the spring

Nitrogen application refined

EM 9014 - Evaluating Soil Nutrients and pH by Depth http://extension.oregonstate.edu/catalog/

https://catalog.extension.oregonstate.edu/

Soil Test Report: Other items

Soil Test Report: Main items  Sample

Phosphorus

Magnesium

Calcium Ca-ppm

Soil pH

33

252

614

1867

5.5

5.7

Olsen

K-ppm

Mg-ppm

Cation Exchange Capacity (CEC) 

Potassium

P-ppm Weak Bray

PNW614

pH



Buffer* Index



1

15

2

12

31

298

780

2520

5.5

5.7



3

9

38

319

791

2651

5.6

5.7







Indicates potential to hold plant nutrients Capacity of soil to exchange cations (Ca, Mg, K, Na, H, Al) Highest in clay soils and high organic matter soils

Base saturation Percentage of exchange sites occupied by basic cations (Ca, Mg, K, Na) If 100%, there is no exchangeable acidity (acidic cations H and Al).

Neither used in OSU fertilizer recommendations  

Not very precise Lack evidence for agronomic response

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Fertilizer and Lime Materials (FG 52)

Cation exchange in action

https://catalog.extension.oregonstate.edu

Compare Soil Test with Crop Needs

Fertilizer Materials

Use OSU Fertilizer Guides (FG) and Pacific Northwest (PNW) bulletins http://extension.oregonstate.edu/catalog/

   

   

N-P-K-S

All values are on a percentage basis (%)

Alfalfa (FG 18, FG 60, PNW 611) Grass & Legume Pastures and Hayground (FG 22, FG 63) Soil Test Interpretation Guide (EC 1478) Other crop fertilizer guides available FG 52 - Fertilizer and Lime Materials FG 76 - Irrigation Water Quality EM 8852- Early Spring Forage Production for W. OR Pastures PNW 614 - Pasture and Grazing Management in the Northwest

Nitrogen N

Phosphorus P2O5

Potassium K2O

Sulfur S

Name

16

16

16

6

Triple-16

46

0

0

0

Urea

21

0

0

24

Ammonium Sulfate (AMS)

11

52

0

0

Mono-AmmoniumPhosphate (MAP)

0

0

60

0

Potash

16

20

0

14

Ammonium-PhosphateSulfate

Quantities of Nutrients from selected fertilizer applications

Soil Test Report: Main items

Fertilizer

lb/a applied

= lb/a N

= lb/a P

= lb/a K

= lb/a S

16-16-16-6 Triple-16

200

32

32

32

12

46-0-0-0 Urea

130

60

0

0

0

21-0-0-24 AMS

200

42

0

0

48

200

22

104

0

0

200

0

0

120

0

Example

Sample

Phosphorus P-ppm Weak Bray

Olsen

Potassium K-ppm

Magnesium Mg-ppm

Calcium Ca-ppm

Soil pH

pH

Buffer* Index

1

15

33

252

614

1867

5.5

5.7

2

12

31

298

780

2520

5.5

5.7

3

9

38

319

791

2651

5.6

5.7

percentage in fertilizer X Amount product applied = pounds nutrient applied __________

FG 63 pH is okay, Ca and Mg are good P is low, add 60 – 100 lb P2O5/ac K is good (>200)

0.16 X 200 = 32

11-52-0-0 MAP 0-0-60-0 Potash

3

Crop-specific pH 

pH 5.5 – 6.5 for grass and clover 





Raising pH with lime  

Sub-clover and tall fescue relatively acid tolerant White clover and orchard grass less tolerant



Ag Lime CaCO3 Dolomite CaMgCO3 Not all Ca products are good liming agents 

pH > 6.5 for alfalfa



Gypsum or CaSO4 does not change pH Rock dust?

Nutrient availability vs. pH Soil Amendments Ag composts  Wood ash 

Analyze as composts or ash (tell lab)  Some increase pH (lower acidity in soil) 

Lime Application Rates

Lime score (rating)

(100-score lime)

If SMP Buffer test for lime is : Under 5.5

Apply this amount of lime (t/a): 4–5



Calcium Carbonate Equivalents (cce)



5.5 – 5.8

3–4



5.8 – 6.1

2–3

Fineness Factor (ff) Moisture factor (mf) Lime score =cce x ff x mf

6.1 – 6.5

1–2

Over 6.5

0-1





pure CaCO3 = 100

Price sources and adjust tonnage applied based on lime score

4

Calculating Lime Savings

Cost Benefit Analysis 

Example need of 60 lb N and 20 lb S per acre

$35 cost to test soil (mailing & Lab fee) of a 10 acre field



AMS = 21-0-0-24



60 lb N/.21 = 286 lb AMS 286 lb AMS x .24 = 69 lb S 286 lb AMS/100 X 110 acidity index



Cost

 



Cost



$120/T lime Guess 2 T/acre Soil test calls for 1 T/acre Difference is 1 T/acre X 10 acre X $120/T = $1200 savings in materials

   

Cost Benefit Analysis

    

Example need of 60 lb N and 20 lb S per acre 

Ureasul (½ AMS + ½ Urea; 33-0-0-12)  



If forage loss is 1 Ton/acre  





Lime not applied 





1 T/ac x 10 acre = 10 T loss Hay $200/T x 10 T = $2,000 loss

 

Difference 



$2000 loss + $1200 not spent = $800 net loss

Acidifying Potential for Fertilizers Fertilizer Ammonium Sulfate Urea Ammonium Phosphate-sulfate

Grade 21-0-0-24

60 lb N/.33 N = 182 lb Ureasul 182 lb Ureasul x .12 S = 22 lb S 182 lb Ureasul/100 x 91 acidity index  = 166 lb lime to neutralize acidity

Cost 

$120/T x 10 T = $1200 not spent

286 lb AMS x $482/T = 286 lb x $482/2000 lb = $68.93 315 lb lime x $120/T = 315 lb x $120/2000 lb = $18.90 Total cost of $87.83 per acre in materials Application cost for 601 lb material Environmental cost of leached sulfur

Calculating Lime Savings

(continued)

Or add too little and suffer production loss

= 315 lb lime to neutralize acidity

182 lb Ureasul x $600/T = 182 lb x $600/2000 lb = $54.60 166 lb lime x $120/T = 166 lb x $120/2000 lb = $9.96 Total cost of $64.56 per acre in materials Application costs of 342 lb of materials

Cost Comparison AMS vs. Ureasul

*Acidity 110

46-0-0

71

16-20-0-13/15

88

Item

AMS

Ureasul

Difference

Materials cost ($/ac)

$87.83

$64.56

$23.27

Materials applied (lb)

601 lb

348 lb

253 lb

Environmental cost (lb S)

49 lb

0 lb

49 lb

Time (hrs.)

X hr.

Y hr.

$Z

*Pounds of 100 score lime needed to neutralize the acidity produced by fertilizer application of 100 lb/ac

5

Fertilizer Application to Pastures & Hay Ground

Seasonal Dry Matter Production

RESULTS

FG 63

Forage Dry Matter, lb/a

Early N application provides early-season forage

3000 2500 2000 1500 4/2 N 1000 2/5 N 500 0 25-Jan 15-Mar 4-May 23-Jun 12-Aug

Traditional Control (0) Early N

Date EM 8852 , https://catalog.extension.oregonstate.edu Early Spring Forage Production for Western Oregon Pastures

EC 1478-E Soil Test Interpretation Guide

Hay Removal Costs Nutrients 

Each ton of typical forage hay removes about 





12 to 15 pounds of phosphate (P2O5) 50 to 60 pounds of potash (K2O)

Also, need to provide about 30 to 50 pounds of nitrogen per acre on grassy stands (i.e. low legume component)

Kopecky, et. al (2008)

Fertilizer Application

Other Sources of Nitrogen 

N2 fixation by legumes 



Fall 



Lime - sampling year  





Ag lime (CaCO3) Dolomitic lime (+Mg)

 

Phosphorus (P) Potassium (K) Some Nitrogen (N)

 

Split applications (early & late)

Sulfur Boron – sampling year



N from urine and feces 



Between hay cuttings 

Amounts (20 – 300 lb N/ac) Available to grasses as legumes die

Nitrogen 

Other nutrients (yearly) 

Spring





Amounts vary w/ source Distribution varies w/ stock

Nitrogen (urea)

6

Fertilizer and Money   

Agronomic response to inputs Improved production Spread over the cost of other inputs   



Time Equipment Fuel

Animal Unit Month (AUM) = Forage 



Animal Unit Month (AUM) = lb of forage required for one animal unit for one month



1000 lb cow eats  

Forage Yield Measure yield (tons of hay and animal unit months carried)



Compare your yield (t/ac) with 

comparable production situations soils interpretation sheets for potential



websoilsurvey.nrcs.usda.gov





Track yield over time with fertilizing according to soil test.

1000-pound cow +/- calf



Use enterprise budget sheets to track forage production costs



Animal Unit (AU)

~

2.5% body wt in feed/day

1000 lb x 0.025 = 25 lb daily feed intake 25 lb/day x 30 days/month = 750 lb/mo

Summary

Soil test and fertilize according to test  Use fertilizer knowledge for least cost  Know your potential yield 

Grow lots of high-quality plants!

Hay Yield = No. bales x bale wt. / ac

= 800 bales x 60 lb/bale / 10 acres = 4,800 lb/ac = 2.4 t/a

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