EDITOR’S NOTE: Earlier this year, we reported on Glendora, Miss., cotton producer Ricky Belk’s plan to enroll 750 acres of highly variable cotton land into a program for variable-rate applications. He initiated the program on Aug. 1, with a variable-rate application of plant growth regulator. This article breaks down how the application was made, according to Belk and his consultant, Billy Bryant. Later in the season, we’ll bring a third installment around defoliation.

A map and a dirt bike are all the precision ag tools that crop consultant Billy Bryant needs to scout and write variable-rate prescriptions for Glendora, Miss., cotton producer Ricky Belk of Adron Farms.

That suits the fast-running consultant just fine. His part in the process doesn’t need to be overly complicated. All he needs to know is where to look and what to do. And as long as everybody is on the same page, it’s as easy as 1-2-3.

In July, Belk and Bryant decided they were almost ready for their first plant growth regulator application on a highly-variable 750-acre field that Belk had pegged for variable-rate applications.

But they decided to wait until a rain before ordering an infrared aerial image from precision agriculture company InTime, based in Cleveland, Miss. Belk noted, “We wanted to see how the cotton responded to the moisture because it had gotten pretty dry. But after it rained, it stayed cloudy for about 10 days, the cotton got waterlogged and we had to wait longer than we wanted before ordering the image.”

An infrared image can indicate how plant biomass is distributed in a growing cotton field and is directly correlated to plant vigor. One use of the image is to generate a scout map, essentially a computer manipulation of the infrared image in which seven management zones are created, ranging from low biomass to high biomass, or low vigor to high vigor.

When Bryant was ready to check the field with the scout map, InTime representative Alan Whitman hand-delivered the map and showed Bryant a few details about how to scout with it.

InTime charges an additional 25 cents per acre if the customer prefers to not use his computer to download scout maps, prescriptions and other information. The charge covers mileage if the customer is within driving distance of a sales representative and overnight delivery charges if he’s not.

After Bryant received his map, he folded it into his shirt pocket, hopped on his Yamaha 250 dirt bike and began to run the field. He can reach just about any point in the field by dirt bike even into mid-August because Belk plants with a 76-inch skip in his cotton. “After about 30 minutes of working off the map, I could usually tell what zone I was in and I would pull out the map to verify that. You can catch on real quick.”

Although Bryant scouted without a GPS-locating device, “an iPAQ with the GPS coordinates is the way of the future, especially on fields that are consistent and there is not a lot of variation. You need to have that iPAQ so you know exactly where you are in relationship to that image.”

Belk and Bryant decided on three prescription rates for the 750-acre field. On zones six and seven, which had the highest biomass, “we put out 24 ounces of plant growth regulator. Zones four and five, in the middle of biomass range, got 12 ounces and Zones one, two and three got zero ounces.

“I called Alan to give him the rates and the day I called him, they delivered a controller card, and Ricky’s driver started putting out the plant growth regulator,” Bryant said. “I watched him spray the cotton. He’d hit the big cotton and it would be like snow coming out, then it would drop back. You could see it regulating as it sprayed. It’s neat.”

If Belk and Bryant had gone with a blanket application, Bryant figures Belk’s driver would have sprayed 16 ounces of plant growth regulator across the board on all the acres. Belk estimated savings of 40 percent in plant growth regulator costs.

The big advantage is not wasting plant growth regulator, Bryant noted. “We’re going to be able to get the exact amount we want where we want it.”

At the time of this writing, Bryant was planning to work in a variable-rate plant bug spray and another plant growth regulator treatment, followed by variable-rate defoliants.

“We’re really excited about improving the quality of our defoliation,” Bryant said. “We think it’s going to be a lot better. We’re going to get those heavy rates where we want them without having to put out more than what we need across the board. These defoliants are expensive.”

This is Bryant’s first experience with variable-rate applications of inputs, although he has grid soil sampled for his clients. He already has a good feeling about the technology.

“I can see where it’s going to be a real good tool for us for plant growth regulators and defoliants. And I think I would feel comfortable doing some applications of insecticide.”

e-mail: erobinson@primediabusiness.com