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Keep it simple and get good counts.

Tom Bechman 1, Editor, Indiana Prairie Farm

May 30, 2010

2 Min Read

My wife spent $5 for a large-size hula-hoop at a major department store. My daughter bought me one for a buck at a dollar store. It's only 27 inches in diameter, but it will still work, developing stand count information in soybean fields. Now that the weather has cleared some and soybeans planted in early to mid-May have had an opportunity to emerge, this is likely a good time to visit fields and determine counts. If you're going to do any replanting, the sooner, it's done, the better the odds that it might return a positive return. That's a story for another day.

Right now concentrate on getting good counts. Shaun Casteel at Purdue University says you can use the hula-hoop on both solid stands and 15-inch rows. If you don't have an actual hoop, you can make one out of number nine wire. The key is to have it perfectly round, and know the diameter of the hoop.

The Purdue University Corn & Soybean Field Guide developed by the Purdue Diagnostic Training Clinic contains instructions and tables on how to sue the hoop. Find them on page 108 in the 2010 edition. Here's an example.

Suppose I roll my 27-inch bargain hoop five times at random location in a 15-inch row field and find an average of 13 soybean plants per hoop. The conversion factor for turning that count into average stand count for plants counted inside a 27-inch diameter hoop is 10,961. So my average population is 13 times 10,961 equals 142,493.

That's still far more than the charts say will return top yield potential. In fact, there are people pushing the planting population down near 140,000 plants per acre. In the field where I took these counts, the planting population averaged 168,500 per acre. At 90% germination and 90% emergence, the variables assumed for years by soybean specialists, the expected stand count would be 136,485. So in this example, there was obviously better germination and or emergence than the twin 90's to produce this stand.

Suppose we used a 30-inch hoop and counted 18 plants. Since the hoop contains more square inches, the multiplication factor will be smaller. For a 30-inch hoop, the factor to multiply the average count of plants inside the hoop by is 8,878. That means that in this case, the expected count would be 159,400.

In either case, both stands are far more than is needed to achieve 100% yield potential.

About the Author(s)

Tom Bechman 1

Editor, Indiana Prairie Farm

Tom Bechman is an important cog in the Farm Progress machinery. In addition to serving as editor of Indiana Prairie Farmer, Tom is nationally known for his coverage of Midwest agronomy, conservation, no-till farming, farm management, farm safety, high-tech farming and personal property tax relief. His byline appears monthly in many of the 18 state and regional farm magazines published by Farm Progress.

"I consider it my responsibility and opportunity as a farm magazine editor to supply useful information that will help today's farm families survive and thrive," the veteran editor says.

Tom graduated from Whiteland (Ind.) High School, earned his B.S. in animal science and agricultural education from Purdue University in 1975 and an M.S. in dairy nutrition two years later. He first joined the magazine as a field editor in 1981 after four years as a vocational agriculture teacher.

Tom enjoys interacting with farm families, university specialists and industry leaders, gathering and sifting through loads of information available in agriculture today. "Whenever I find a new idea or a new thought that could either improve someone's life or their income, I consider it a personal challenge to discover how to present it in the most useful form, " he says.

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