Math meets real life.

This Soils and Streams column first appeared in the March 10, 2018, issue of the Kearney Hub.

Agriculture is ‘sweet spot’ where math, real-world problems mix

Kids who don’t enjoy math are prone to ask, “When will I ever use this?” Teachers attempt to give real-world examples, and students remain skeptical — it’s a time-worn scenario.

Scholastically, word problems are the key to real-world application, and I don’t know any kid who adores word problems. Numbers and words may as well be oil and water.

Agriculture is a sweet spot of math meets real world. My husband isn’t fond of math, and yet his calculation ability is really sharp because he uses it every single day.

Seasonally, he’s figuring cattle rations to get the weights of various feeds in the feed wagon correct, determining seed spacing, checking a custom applicator’s final spray rate, calculating a ballpark yield by counting ears and using a formula, or figuring loss behind the combine.

He always carries a nearly worn-out pocket calculator, a scrap of paper and a pen, and sometimes a reference such as an Extension guide. But the tools are useless if you don’t know how to use them. (Kids, pay attention in math!)

I’m a math geek married to a farmer, and my interests skew those directions — maybe more than is socially acceptable. The calculations that are some people’s literal bread (there’s 23 ounces of wheat in a grocery-store loaf) and butter (one stick comes from about five pounds of milk) are fun trivia for me.

But there’s more!

Years ago, as a freshly-minted CDL holder waiting in a long, long line of trucks at the Coors elevator in Monte Vista, Colorado, I coaxed my sister into asking the elevator manager how much barley was used for a single can of beer. Answer: About 1.53 ounces.

Using her figure and the numbers on my scale ticket for that load, my sister and I calculated that our truck held the raw material to make about 63,666.67 cans of beer.

Tell you what, a beer-can number that big interests a lot of people — farm kids and town kids alike. That’s bar small-talk gold for an introverted math major at a small college in central Kansas.

How’s it figured? Test weight for Coors’ proprietary malting barley is about 54 pounds per bushel. A typical semi load is about 1,000 bushels. So, (54 pounds per bushel)(1000 bushels)(16 ounces per pound)/(1.53 ounces per can) = 564,706 cans.

Of course, not everyone is interested in beer, and agriculture is more than just food. Here are some other fun calculations.

• Beef. My husband keeps back one steer from each year’s calf crop for our family to eat later. Meat is a high-dollar food item for our household of seven, and this makes a lot of sense for us.

What should you expect for meat if you buy a beef animal and have it processed at a nearby locker? Averages are helpful for planning, but yield is always a bit of a surprise.

About 61.5 percent of a live animal is the part that goes into meat processing (hanging weight). Depending on what cuts and parts you prefer to use, the take-home weight is about 55 percent of the hanging weight. That goes up if you take home things like the heart and liver, fat to make tallow, or bones for broth.

We typically have a steer butchered at about 2 years old and about 1,200 to 1,350 pounds.

So, the calculations: (1,300 pounds)(0.615) = 799.5 pounds hanging weight. Then, (799.5 pounds)(0.55) = 439.7 pounds of take-home meat.

We expect half that to be ground beef, but we’ll also come home with brisket, T-bone and a whole bunch of other great food.

• Pencils. My fact-finding mission for this calculation led me to the websites of Sierra Pacific Industries, whose sawmills and kilns provide moisture-stabilized incense cedar wood to pencil manufacturers, and Dixon Ticonderoga, the manufacturer of pencils I like.

I used a ruler and a caliper to measure a hexagonal Ticonderoga pencil; it’s 7 inches long, and its diameter is 0.285 inches. It’s a painted pencil, so some of that diameter is paint.

To make pencils, cedar boards are cut into slats. Two slats are sandwiched together around graphite leads, then cut out to make pencils. Taking a thin saw blade into consideration, 3-inch-wide slats would permit cutting 10 pencils across.

In an error- and defect-free scenario, a 3-inch by 3-inch by 10-foot board would make 17 blocks of wood 7 inches long; each would make 100 pencils, for a total of 1,700 pencils.

Seventeen hundred pencils would keep even my fourth-grader supplied.

• Jeans. My brother and sister-in-law’s wedding took place in December in the Texas Panhandle. It had been many years since I’d been in cotton country during picking time, and the wedding was at a venue surrounded by fields of future jeans.

For this, I referred to the USDA’s NASS website and the blog of Janet Person, an avid agvocate.

Cotton plants actually produce two products — lint and seed. These are separated at the gin.

In 2017 in Texas, the average harvested acre of cotton (statewide, good production and bad combined) produced 793 pounds of cotton lint. I weighed a pair of my own jeans. They’re 18.8 ounces and 71 percent cotton, so they contain about 13.3 ounces of cotton.

So, 793 pounds is 12,688 ounces, meaning that in a waste-free scenario, Maurices could make about 954 pairs of size 9/10 DenimFlex bootcut jeans from the 2017 production of one typical Texas acre.

A new pair every day for almost three years — I’d run out of closet space.

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