Lab 7: Light, Temperature, and Water
Rachel Veenstra 
AGRON 220 Lab: Crop Response to Light, Temperature, and Water
A worksheet to walk you through the seventh lab session
Task 1: Consider each scenario below and discuss the questions with your group. Take notes on key points you come up with, and be ready to share your answers with the class!
Scenario A:
Your friend is concerned about their corn because it is not getting taller. The corn is dry and stressed.
Do you think the leaf stomata are open or closed?
Is photosynthesis occurring?
What about photorespiration?
Why are the plants not getting taller?
Scenario B:
I was excited to get the season started and planted my grain sorghum the first time my soil temperature hit 60F. Three weeks later, my crop still has not come up!
Should I give up on my crop?
What could cause this problem?
What should I do differently in the future?
Scenario C:
Your friend wanted to get as much grain yield as possible to win the Kansas soybean yield contest. They planted soybeans at a very high population. Some of the plants look really weird now - many are really tall and yellow-looking. Some are even wilting!
What caused the plants to get really tall and what is this response called?
Why might the plants be wilting?
What should be done differently in the future?
Scenario D:
You are growing wheat in Western Kansas and it has not rained in a month. Your plants look pretty bad, but then a rain comes and your plants look healthy within several days.
What root anatomy component allowed the plants to survive?
What is needed for water to enter the plant and move through the plant to reach the atmosphere?
What is this water loss through plants called?
Task 2: With your group, look up cardinal temperature requirements for five crops of your choice. Use Extension resources when possible, and have good references to back up your answers! A temperature range is okay.
Crop
Base temperature
Optimum temperature
Maximum temperature
#1
#2
#3
#4
#5
Task 3: With the data your group is given, calculate the GDD per day your two crops would have accumulated.
Crop 1
Crop 1
Day 1
Day 1
Day 2
Day 2
Day 3
Day 3
Day 4
Day 4
Day 5
Day 5
Day 6
Day 6
Day 7
Day 7
Total (add days together)
Total
Task 4: Navigate to the "Chartistic" app on your iPad or draw a graph on your datasheet similar to the one shown below. Enter the data from your calculations above to make a chart for each crop, similar to the one shown below.
Include the crop name and your group number in each graph title.
As you finish each graph, show it to your instructor (on paper) or save it by clicking the checkmark in the top corner of the screen, and send it (via AirDrop) to "Dr. Veenstra's iPad".
Task 5: Navigate to the U2U online Decision Support Tool with the link or QR code below. Familiarize yourself with the platform using the A B C steps below.
A) On the map, select the home county of someone in your group.
Direct link:
B) A window will pop up. Click "Create GDD graph".
C) Adjust the options at the top to see how it changes the graph.
Explore the following scenarios and answer each question using the U2U Decision Support Tool.
Pick another home county in your group.
Assume you planted corn on May 15, 2022.
Leave the comparison year blank.
Pick your CRM (corn maturity days) based on the map.
Do not change your silking GDDs.
What is the projected date for your corn to reach the R1 stage?
What is the projected date for your corn to reach the R6 stage?
What date is the earliest frost could be expected?
Is your crop in danger of freezing?
Pick another home county in your group.
Assume you planted corn on June 1, 2022.
Leave the comparison year blank.
Pick your CRM (corn maturity days) based on the map above.
Do not change your silking GDDs.
What is the projected date for your corn to reach the R1 stage?
What is the projected date for your corn to reach the R6 stage?
What date is the earliest frost could be expected?
Is your crop in danger of freezing?
Pick another home county in your group (or a random one).
Assume you planted corn on June 15, 2022.
Leave the comparison year blank.
Pick your CRM (corn maturity days) based on the map above.
Do not change your silking GDDs.
What is the projected date for your corn to reach the R1 stage?
What is the projected date for your corn to reach the R6 stage?
What date is the earliest frost could be expected?
Is your crop in danger of freezing?
Task 6: With the data your group is given, calculate the water use (in inches) of each crop for 1 week.
Crop 1
Crop 2
Total
Total
Task 7: Complete the following farmer calculations.
Assume you have irrigation capacities on both of these fields. Each field is a 120-acre circle with a pivot to supply irrigation.
Your well for Crop 1 can pump 600 gallons per minute (GPM).
Your well for Crop 2 can pump 850 GPM.
Remember that an acre-inch is 27,154 gallons of water
Question 1: How many hours would it take for your Crop 1 pivot to apply 1 acre-inch to your ENTIRE field?
Answer 1:
hours/field-inch
How much water (in field-inches) could you put on your ENTIRE Crop 1 field in a week?
field-in/week
Is the answer to the previous question enough to satisfy the weekly demand you calculated for Crop 1?
(yes or no)
Question 2: How many hours would it take for your Crop 2 pivot to apply 1 acre-inch to your ENTIRE field?
Answer 1:
hours/field-inch
How much water (in field-inches) could you put on your ENTIRE Crop 2 field in a week?
field-in/week
Is the answer to the previous question enough to satisfy the weekly demand you calculated for Crop 2?
(yes or no)
Task 8: Go to the greenhouse! Arrange plants CAREFULLY on the floor to achieve the following canopy coverage percentages: (pictures must be taken at least waist-high, % must be within 5%)
30%
60%
90%
Other worksheets of Natural science: Plants
