Fertilizer Recommendations for Irrigated Corn, Sorghum, and Sudan

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Section Plant Soil Science Unit Soil
Management Lesson Title Lesson 3 Fertilizer
Recommendations and Fertilizer Adjustments Lab
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Bake some chocolate cookies!
Slide 1

• You are making 200 cookies
• You have the following quantities of ingredients
• 3/4 lbs of butter 2 teaspoons of salt
• 1 ½ cups of brown sugar 1 teaspoon of baking soda
• 2 cups of sugar 1 cup of chopped nuts
• 5 eggs 6 cups of chocolate chips
• 2 teaspoons of vanilla
• 8 cups of flour

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Actual quantities needed
Slide 2

• You had the following quantities of ingredients
• 3/4 lbs of butter 2 teaspoons of salt
• 1 ½ cups of brown sugar 1 teaspoons of baking
  soda
• 2 cups of sugar 1 cup of chopped nuts
• 5 eggs 6 cups of chocolate chips
• 2 teaspoons of vanilla
• 8 cups of flour

Adequate Deficient Excessive

• You need the following quantities of ingredients
• 1 lb of butter 2 teaspoons of salt
• 2 cups of brown sugar 2 teaspoons of baking
  soda
• 2 cups of sugar 2 cups of chopped nuts
• 4 eggs 4 cups of chocolate chips
• 3 teaspoons of vanilla
• 4.5 cups of flour

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PSS 4 Making Fertilizer Recommendations
Slide 3

• Student Learning Objectives (Enablers)
• As a result of this lesson, the student will
• Use given data to make fertilizer recommendations
  for crops in Colorado.
• Be able to complete the fertilizer recommendation
  part of the Colorado Land Classification CDE.

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Fertilizer Recommendations for Irrigated Corn,
Sorghum, and Sudan
Slide 4
NITROGEN NITROGEN NITROGEN NITROGEN NITROGEN NITROGEN
Soil Test NO3-N Soil Test Soil Organic Matter Soil Test Soil Organic Matter Soil Test Soil Organic Matter Soil Test Soil Organic Matter Soil Test Soil Organic Matter
Soil Test NO3-N 0-0.5 06-1.0 1.1-1.5 1.6-2.0 gt2.0
Ppm 0-0.5 06-1.0 1.1-1.5 1.6-2.0 gt2.0
Ppm (lbs/A fertilizer N) (lbs/A fertilizer N) (lbs/A fertilizer N) (lbs/A fertilizer N) (lbs/A fertilizer N)

0-6 250 235 220 205 190
7-12 220 205 190 175 160
13-18 190 175 160 145 130
19-24 160 145 130 115 100
25-30 130 115 100 85 70
31-36 100 85 70 55 40
37-42 70 55 40 0 0
43-48 40 0 0 0 0
gt48 0 0 0 0 0
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Fertilizer Recommendations for Irrigated Corn,
Sorghum, and Sudan
Slide 5
Phosphorous Phosphorous Phosphorous
Soil Test P Fertilizer P

(ppm) Lbs/A P2O5

0-3 80
4-7 50
8-11 30
gt11 0
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Slide 6
Fertilizer Recommendations for Irrigated Corn,
Sorghum, and Sudan
Potassium Potassium Potassium
Soil Test K Fertilizer K

(ppm) Lbs/A K2O

0-60 64
61-120 40
gt120 0

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Zinc recommendations for all crops
Slide 7
ZINC ZINC ZINC ZINC
Soil Test ZINC Irrigated Dryland
Soil Test ZINC
Soil Test ZINC (lbs/A fertilizer Zn) (lbs/A fertilizer Zn) (lbs/A fertilizer Zn)

PPM Sensitive Crops (corn, sorphum, sudan, beans, potatoes) Sensitive Crops (corn, sorphum, sudan, beans, potatoes) Sensitive Crops (corn, sorphum, sudan, beans, potatoes)
0-0.9 10 5
1.0-1.5 5 0
gt1.5 0 0
Other Crops Other Crops Other Crops Other Crops
0-0.5 5 0
gt0.5 0 0

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Iron recommendations for all crops
Slide 8
Iron Iron Iron
Soil Test Fe Iron recommendation Fe Sensitive crops only (corn, sorghum, sudan, beans, potatoes
Soil Test Fe
(ppm)

0-3.0 Soil is deficient in available FE and corrective application will likely be beneficial.
3.1-5.0 Soil is marginally deficient in available iron and application may or may not be necessary.
gt5.0 No Fe fertilization is required

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Soluble Salts
Slide 9

Crop Low Moderate High

Electrical Conductivity (mmhos/cm) Electrical Conductivity (mmhos/cm) Electrical Conductivity (mmhos/cm)

Sensitive Pinto beans, potatoes 0-2.5 2.6-5.0 gt5.0
Moderately tolerant Corn, sugarbeets, millet, oats, alfalfa seeding, all grasses 0-4.0 4.1-8.0 gt8.0
Tolerant Sorghum, barley, wheat, sudangrass, established alfalfa, forage sorphum x sudan 0-6.0 6.1-12.0 gt12.0
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Land Judging Scorecard
Slide 10
FERTILIZER TREATMENT (5 points
each) Recommendations in lbs/A _____ NO3-N _____
P2O5 _______ K2O _____ Zn _____ Fe SOLUBLE
SALT LEVEL (5 points) ? low ? moderate ? high
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Assessment
Slide 11
Crop to be fertilized------------Irrigated
Corn Organic matter content-------1.0 Nitrogen
soil test--------------25 ppm Phosphorous soil
test---------7 ppm Potassium soil
test------------121 ppm Zinc soil
test--------------------0.8 ppm Iron soil
test--------------------5.1 ppm Soluble salt
reading-----------7.9mmhos/cm
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Answers to Assessment
Slide 12

• 115 lbs/A of N03-N
• lbs/A of P2O5
• 0 lbs/A of K2O
• lbs/A of Zn
• 0 lbs/A of Fe
• Moderate level of Soluble Salts

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Fertilizer worksheet for Irrigated corn, sorghum
and sudan for grain

• Step 1. Find Organic Matter and Write it
  here____________________
• Step 2. Find the Nitrogen PPM and write it
  here__________________
• Step 3. Using both numbers on the chart write
  your initial N rec. here______________
• Step 4. Subtract yield goal from 150 and write
  number here___________________
• Step 5. If step 4 answer is zero then write step
  3 answer on score sheet.
• Step 6. If step 4 answer different then zero go
  to step 7.
• Step 7. Take Step 4 answer divided by 25 and
  write answer here________________
• Step 8. Take step 7 answer and multiply by 40
  and write answer here______________
• Step 9. If yield goal is greater than 150 ADD
  step 8 answer to step 3 number and write total
  answer on score sheet.
• Step 10. If yield goal is less than 150 SUBTRACT
  step 8 answer from step 3 answer and write total
  answer on score sheet.

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Fertilizer Worksheet for corn, sorghum, and sudan
used for silage

• Step 1. Find Organic Matter and Write it
  here____________________
• Step 2. Find the Nitrogen PPM and write it
  here__________________
• Step 3. Using both numbers on the chart write
  your initial N rec. here______________
• Step 4. Subtract yield goal from 30 and write
  number here___________________
• Step 5. If step 4 answer is zero then write step
  3 answer on score sheet.
• Step 6. If step 4 answer different then zero go
  to step 7.
• Step 7. Take Step 4 answer divided by 10 and
  write answer here________________
• Step 8. Take step 7 answer and multiply by 40
  and write answer here______________
• Step 9. If yield goal is greater than 30 ADD
  step 8 answer to step 3 number and write total
  answer on score sheet.
• Step 10. If yield goal is less than 30 SUBTRACT
  step 8 answer from step 3 answer and write total
  answer on score sheet.

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Fertilizer Worksheet for Irrigated grass, grass
legume hay, pasture and mountain meadows.

• Step 1. Find Organic Matter and Write it
  here____________________
• Step 2. Find the Nitrogen PPM and write it
  here__________________
• Step 3. Using both numbers on the chart write
  your initial N rec. here______________
• Step 4. Subtract yield goal from 4 and write
  number here___________________
• Step 5. If step 4 answer is zero then write step
  3 answer on score sheet.
• Step 6. If step 4 answer different then zero go
  to step 7.
• Step 7. Take Step 4 answer multiply by and
  write answer here________________
• Step 8. If yield goal is greater than 4 ADD step
  7 answer to step 3 number and write total answer
  on score sheet.
• Step 9. If yield goal is less than 4 SUBTRACT
  step 7 answer from step 3 answer and write total
  answer on score sheet.

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Fertilizer worksheet for Dry-land Winter Wheat
and other small grains

• Step 1. Find Organic Matter and Write it
  here____________________
• Step 2. Find the Nitrogen PPM and write it
  here__________________
• Step 3. Using both numbers on the chart write
  your initial N rec. here______________
• Step 4. Subtract yield goal from 50 and write
  number here___________________
• Step 5. If step 4 answer is zero then write step
  3 answer on score sheet.
• Step 6. If step 4 answer different then zero go
  to step 7.
• Step 7. Take Step 4 answer divided by 10 and
  write answer here________________
• Step 8. Take step 7 answer and multiply by 25
  and write answer here______________
• Step 9. If yield goal is greater than 50 ADD
  step 8 answer to step 3 number and write total
  answer on score sheet.
• Step 10. If yield goal is less than 50 SUBTRACT
  step 8 answer from step 3 answer and write total
  answer on score sheet.