Keith Jolley, Farmer from Jamaica, IL
More Career Connections
 There
is a lot of mathematics in farming! With farming, you
have to able to use different areas of mathematics,
such as weights and measures, addition, subtraction,
multiplication, division, rates and ratios, geometry
and area, interest rates, and taxes.
We
farmers do quite a bit with conversions. For example,
grain has always been sold in bushels. However, when
we harvest a field, we know the weight of the corn or
soybeans we’ve brought in. So we use the fact that a
bushel of soybeans weighs 60 lb. and a bushel of corn
weighs 50 lb. to calculate how much of each we have
to sell.
The
size of a field is measured in acres. An acre is equal
to 160 square rods. (These are very old measures that
farming has carried through the years.) A rod is equal
to 16 1/2 feet. That means that an acre is 43,560 square
feet. All farmers know how long and wide their fields
are and use that to convert feet into acres.
When
we plant corn, we like to plant about 30,000 seeds per
acre. With beans, we plant about 18,000 seeds per acre.
There are new planters now that will tell us as we drive
through the field how many seeds per acre we are planting.
However, it is still good to check how much we’ve planted
by digging up a small area and counting the seeds that
have been planted there. Once we know how many seeds
per foot are being planted in that row and how close
the rows are, we can do the math to figure out if we
are planting the right amount (and if not, what type
of adjustments we need to make).
With
fertilizers, we generally spread 200-400 lb. per acre.
We run soil tests to determine how much of which fertilizer
we need. Now there are new spreaders with computers
that allow us to enter a map of the field that it will
use to adjust the amount of fertilizer it applies as
we drive along. We are also starting to use farm machines
that are linked by satellites. Right now, however, those
are still pretty expensive.
Farmers
also have to know mathematics to think about interest
rates. There is quite a difference between 6.5% and
14%. We also use mathematics when deciding what to plant
and when to sell. We watch the prices. It is kind of
strange. If it rains in Brazil, then the price of beans
drops. It takes something really good to happen to make
the prices go up. But that’s farming!
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