Section: Plant & Soil Science

Unit: Soil Management

Lesson Title: Lesson 3: Fertilizer Recommendations and Fertilizer Adjustments Lab

Bake some chocolate cookies!

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

Slide #1

Actual quantities needed 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

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

Adequate

Deficient

Excessive

Slide #2

PSS #4 Making Fertilizer Recommendations

Student Learning Objectives (Enablers)

As a result of this lesson, the student will:

1. Use given data to make fertilizer recommendations for crops in Colorado.

2. Be able to complete the fertilizer recommendation part of the Colorado Land Classification CDE.

Slide #3

Fertilizer Recommendations for Irrigated Corn, Sorghum, and Sudan

NITROGEN*

Soil TestNO3-N

Soil Test % Soil Organic Matter

0-0.5 06-1.0 1.1-1.5 1.6-2.0 >2.0

Ppm(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

>48 0 0 0 0 0

Slide #4

Fertilizer Recommendations for Irrigated Corn, Sorghum, and Sudan

Phosphorous

Soil Test P

Fertilizer P

(ppm) Lbs/A P2O5

0-3 80

4-7 50

8-11 30

>11 0

Slide #5

Potassium

Soil Test K

Fertilizer K

(ppm) Lbs/A K2O

0-60 64

61-120 40

>120 0

Fertilizer Recommendations for Irrigated Corn, Sorghum, and Sudan

Slide #6

Zinc recommendations for all crops

ZINC

Soil TestZINC

Irrigated Dryland

(lbs/A fertilizer Zn)

PPM Sensitive Crops(corn, sorphum, sudan, beans, potatoes)

0-0.9 10 5

1.0-1.5 5 0

>1.5 0 0

Other Crops

0-0.5 5 0

>0.5 0 0

Slide #7

Iron recommendations for all crops

Iron

Soil Test Fe

Iron recommendationFe Sensitive crops only

(corn, sorghum, sudan, beans, potatoes

(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.

>5.0 No Fe fertilization is required

Slide #8

Crop Low Moderate High

Electrical Conductivity(mmhos/cm)

SensitivePinto beans,

potatoes

0-2.5 2.6-5.0 >5.0

Moderately tolerant

Corn, sugarbeets, millet, oats, alfalfa

seeding, all grasses

0-4.0 4.1-8.0 >8.0

TolerantSorghum, barley,

wheat, sudangrass,

established alfalfa, forage sorphum x

sudan

0-6.0 6.1-12.0 >12.0

Soluble Salts Slide #9

Land Judging ScorecardSlide #10

FERTILIZER TREATMENT(5 points each)

Recommendations in lbs/A_____ NO3-N_____ P2O5

_______ K2O_____ Zn_____ Fe

SOLUBLE SALT LEVEL(5 points) low

moderate high

Assessment

Crop to be fertilized------------Irrigated CornOrganic matter content-------1.0%Nitrogen soil test--------------25 ppmPhosphorous soil test---------7 ppmPotassium soil test------------121 ppm

Zinc soil test--------------------0.8 ppmIron soil test--------------------5.1 ppm

Soluble salt reading-----------7.9mmhos/cm

Slide #11

Answers to Assessment

115 lbs/A of N03-N50 lbs/A of P2O50 lbs/A of K2O

10 lbs/A of Zn0 lbs/A of Fe

Moderate level of Soluble Salts

Slide #12

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.

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.

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.

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.