Real-Life Math
Every crop farmer is a plant physiologist, sort of. Each year, crop
farmers take note of how much yield (total amount of usable crops) their growing
produced. However, farmers generally do not record their results as carefully
and with as much detail as plant physiologists do. That's why the National
Corn Grower's Society asked you, a professional plant physiologist, to
test the effects of a new nitrogen fertilizer they developed. They want you
to determine whether this new fertilizer is cost-effective for members of
their society to use.
Norm Hopper is an associate professor of plant
and soil science. "Plant physiologists often perform research programs, like
testing the effects of different fertilizers, in order to better understand
the plants themselves, and to help farmers produce the best yields," he says.
To
test this new nitrogen fertilizer, you planted 5 acres of corn at the beginning
of last year's growing season. You added no fertilizer to the first acre
of corn crops -- this acre was the control group. You added 40 pounds of the
fertilizer to the second acre of corn, 80 pounds of fertilizer to the third,
140 pounds to the fourth and 160 pounds to the fifth.
Throughout the
growing season, you spent a lot of time in the field measuring the corn's
response to the fertilizer. Among other duties, you measured how fast the
corn stalks in each acre were growing and determined the dry weight of plant
samples at particular times throughout the season. "When performing these
measurements, it's important to do them carefully and calculate exact
amounts," says Hopper.
At the end of the season, the crops were harvested
and the yields registered. The control group (the first acre) yielded 100
bushels of corn. The second acre yielded 120 bushels; the third acre yielded
145; the fourth acre yielded 170; and the fifth acre also yielded 170 bushels
of corn.
Now you have all the information you need to answer the National
Corn Grower's Society's question: if the market price of this fertilizer
is $1 a pound, and a bushel of corn sells for $2, is it worth it for our members
to use this fertilizer? And, if so, what is the best amount of fertilizer
to buy and use per acre of corn planted?