Soil pH Data: Averages, Crop Match and Fixes

SubstitutePlans.com
Career and Technical Education · Agriculture / FFA
SP-AG-002 · Free to print and use in your classroom · substituteplans.com
Page 2
Soil pH Data: Averages, Crop Match and Fixes
Career and Technical Education · Agriculture / FFA · Grades 9-11 · 50 minutes
Time needed
50 minutes (one class period)
Prep
Copy the 2-page worksheet (one per student). Calculators are optional. Nothing else to
prepare.
Technology
None. Calculators are optional for adding and dividing.
Student
independence
High. Students work alone, then compare with a partner.
Copies to make
One 2-page worksheet per student
Materials
Pencils, Worksheet, Calculators (optional)
Goal for today: Students will calculate average pH from sample readings, classify soil as acidic, neutral or alkaline,
and match plots to crops using given pH ranges.
Before the bell
☐ Copy the worksheet, one per student (2 pages).
☐ This is a paper-only lesson. Students must not handle soil, test kits, chemicals or any equipment. All data is
on the page.
☐ Write on the board: pH below 7 = acidic. pH 7 = neutral. pH above 7 = alkaline.
☐ Keep the answer key on your desk. You do not need to know soil science.
Say this to start
Good morning! Your teacher left an agriculture lesson about soil pH. pH is a number that tells how acidic or alkaline soil
is. A farmer tests soil and uses the numbers to pick the right crop. Today you are the farmer. All the data is on your
worksheet, and everything is done on paper.

SubstitutePlans.com
Career and Technical Education · Agriculture / FFA
SP-AG-002 · Free to print and use in your classroom · substituteplans.com
Page 3
Run of show
Minutes
What you do
What students do
0–5
Take attendance the way the school requires. Hand out the
worksheets and read the three pH rules on the board
aloud.
Settle in and read the directions.
5–10
Read this example aloud: three readings 5.0, 5.5 and 6.0
add up to 16.5. Divide by 3 to get an average of 5.5. Tell
students that is how they find each plot’s average.
Follow the example and copy it in the
margin if they like.
10–22
Tell students to fill in the Average and Acidic or alkaline
columns of the table.
Add three readings, divide by 3, and
classify each plot.
22–40
Tell students to answer questions 1–10 using their table
and the crop range table. Walk the room and point stuck
students to the board rules.
Match plots to crops, subtract to find
differences and answer true/false
questions.
40–46
Tell students to answer questions 11 and 12 in complete
sentences.
Write short explanations.
46–50
Read the table averages aloud from the key. Students
check their work. Collect all worksheets and stack them for
the teacher.
Check averages. Hand in the worksheet.
If things go wrong
• If students ask where the soil samples are, explain that the lesson is on paper only and the numbers are
already on the worksheet. Nobody handles soil or equipment today.
• If a student gets a long decimal for an average, tell them the readings were chosen to come out to one
decimal place. Ask them to re-add the three readings.
• If a student finishes in under 25 minutes, check that every average is written, then use the early finisher list.
• If students argue about question 11 or 12, remind them those are open-ended and the key lists sample
answers.
Early finishers
• Make up three pH readings that average exactly 6.5. Trade with a neighbor to check.
• Explain in two sentences why a farmer should not test just one spot in a big field.
• Rank the six plots from most acidic to most alkaline on the back of the worksheet.
Support and challenge
• Support: Allow calculators and let students do only the table and questions 1–3, 7, 8 and 10.
• Challenge: Ask students to calculate the range (highest minus lowest reading) for each plot and decide which
plot had the most consistent readings.

SubstitutePlans.com
Career and Technical Education · Agriculture / FFA
SP-AG-002 · Free to print and use in your classroom · substituteplans.com
Page 4
Notes for the teacher (you fill this in)
Jot a few lines before you leave. A full Daily Sub Report is in the free Sub Survival Kit at SubstitutePlans.com.
How far the class got / what to pick up next:
Students who were especially helpful:
Anything the teacher should know: