Agriculture in Idaho: The Risky Farmer
Economics, Irrigation Use, and Climate Variability
2015 Adventure Learning Activity by Andrea Leonard
Target Age Group: 9th-12th grade
Duration: 50 minute class period
Materials: Dice
Spreadsheet (Attached)
Activity Summary:
In this lesson, students will use the probability of rolling a dice to discover how
interannual precipitation variability effects farmers’ decisions on crop choice and the resulting
economic outcomes. They will discuss the issues and risks facing farmers when deciding what
crops to plant with uncertain water allotments.
Background:
Agriculture is extremely important to Idaho’s economy. The top five agricultural products in the
state are dairy products, cattle, potatoes, wheat, and hay. Fertile soil of the region provides
excellent conditions for diverse agricultural products. Southwestern Idaho’s average
precipitation is around 12 inches per year, much less than the required amount to sustain the
immense supply of crops grown in the valley. To make up for the lack of precipitation, irrigation
is needed to supply water to agricultural land. Idaho is the second largest irrigating state in the
United States, as shown in the figure below, with 85% of our water use going toward irrigation.
(USGS.gov)
Most of Idaho’s irrigation supply comes from surface runoff from higher elevations that
is then stored in reservoirs such as Lucky Peak, Arrow Rock, and Anderson Ranch. In
southwestern Idaho, irrigation districts control water allotment amounts that are then
distributed to farmers. These allotments are measured in acre-feet; an acre-foot is the volume
of one acre of surface area to a depth of one foot. Depending on the reservoir storage that
year, allotments can range in acre-feet, causing potential water shortages for certain crops.
When students play the game, they will simulate what farmers go through making
decisions about what to grow. Although farmers have research and often experience to support
their decisions, with all the risks involved for each different crop, it’s still a risky business. To
emphasize the risks as well as the rewards, water allotments, prices, and yields are consistent
with Idaho’s agricultural economy. Understanding farming practices and the consumptive water
use associated with the food we eat will help students appreciate the food supply that many
people take for granted. They will become more informed of farming practices and farmer
decision making, develop knowledgeable opinions, and become more involved in their world as
food consumers.
Big Ideas: Students will understand that…
1. Interannual climate variability is expected to increase as the climate continues to
change (Challinor, 2009), and therefore farmers must adapt to climate variability in
order to maintain successful farms.
2. Yearly precipitation determines water allotments distributed to farmers. Farmers must
make risky decisions based on the amount of water they receive, which may alter the
profits they receive.
3. Global population growth is causing a heavy demand for the increase in world food
production. This puts even more pressure on agricultural land and the natural resources
that provide for us (water, soil, etc.).
Directions:
1. Roll the dice to determine your water allotment for this year: Record your roll in the
“DICE ROLL FOR ALLOTMENT” box on the spreadsheet.
1 = no water right granted
2 = 1.5 acre feet = 18 inches
3 = 1.8 acre feet = 22 inches
4 = 2.4 acre feet = 29 inches
5 = 2.8 acre feet = 34 inches
6 = 3 acre feet = 36 inches
-This is the water granted to you by the irrigation districts to help grow your plants this year. Fill
the “ALLOTMENT” box on the activity board with this supply (in inches).
2. The average growing season (May-September) precipitation in southwestern Idaho is
around 3 inches.
Your allotment (from above)_ + 3 in. = _________
-This is your total amount of water to be used to grow your crops. Fill the “TOTAL ALLOTMENT”
box on the activity board with this number.
3. Different crops require different amounts of water to grow to their full potential.
(FAO.org)
Crop Type
Water Needs
Potato
22 inches
Sensitivity to
Drought
Low-medium
Corn
24 inches
Medium-high
Sugarbeet
25 inches
Low-medium
Alfalfa
38 inches
Low-medium
-Pick a crop whose water needs are met by your total water allotment. If you were not granted
a water right this year, or do not have enough water for any of the crops, allow your plot to lay
fallow, or do not plant any crops. In this case, see step 6. Allowing a field to lay fallow also
provides time for soil enhancement and nutrient regrowth.
-Record your crop type that you will grow this season in the “CROP GROWN” box of the
spreadsheet.
4. Many factors are responsible for the yield of a specific type of crop, and seasonal
variability is expected by farmers. The reasons for this unpredictability include fertilizer
application, how efficient the irrigation system is, rainfall amounts, and more. Roll the
dice for your yield, for your specific crop. Record dice roll in “DICE ROLL FOR YIELD” box
on spreadsheet. These are reasonable ranges of yields for each crop grown in Idaho.
(National Agricultural Statistics Service, 2014 data)
Dice Roll
Yield
1
5
2
9
3
14
4
16
5
20
6
22
3
140
4
160
5
180
6
200
3
30
4
35
5
40
6
45
Potato (in tons per acre)
Dice Roll
Yield
1
50
2
100
Corn (in bushels per acre)
Dice Roll
Yield
1
10
2
20
Sugarbeet (in tons per acre)
Dice Roll
Yield
1
2
2
3
3
5
4
7
5
10
6
12
Alfalfa (in tons per acre)
-After rolling the dice and finding the associated seasonal yield, record that amount in the
“TOTAL YIELD PER ACRE”.
5. Now you have a yield of your harvested crop at the end of the growing season. Convert
this to profit by multiplying it by the average price of your commodity. These profits
take into account fertilization, machinery, and labor costs. (NASS.USDA.gov)
Crop Type
Average Profit per unit
Potato
$70/ton
Corn
$2/bushel
Sugarbeet
$25/ton
Alfalfa
$150/ton
TOTAL YIELD PER ACRE x Price per unit (from table above) = Profit per acre
Record your “PROFIT PER ACRE” on the spreadsheet.
Don’t worry, this is not your yearly profit- farms are larger than one acre! The average
non-industrial farm size in Idaho is around 400 acres, so multiply your profit per acre
by 400.
PROFIT PER ACRE x 400 = TOTAL YEARLY PROFIT
6. Record your “TOTAL YEARLY PROFIT” on the worksheet. This is how much you have
earned this year. If you did not plant any crops and have let your farm lay fallow,
collect $50,000 in government subsidies.
7. Repeat steps 1-6 for the remaining 4 years. Add up your profits for all 5 years and
record in the “TOTAL 5 YEAR PROFIT” box at the bottom of the spreadsheet. As you
can see, everyone has very different numbers. This demonstrates the variability and
unpredictability of farming.