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Paired Row Planting Improves Weed Control

Thursday, February 1, 2001
filed under: Weeds

Paired Row Planting Improves Weed Control

With only minor machinery modifications, paired row sunflower develop canopy closure two weeks earlier than 30-inch rows

Paired row planting can help improve weed control in sunflower, and better yet, the practice is economical. Only a minor modification to the three-point hitch attachment of existing planters is all that is needed to achieve paired-row planting, and no change is necessary for harvesting.

The last two growing seasons, Troy Price and Dr. Phillip Stahlman have tested paired row planting along with treatments of Spartan for improved weed control in sunflower. Price is a weed scientist at the Kansas State University Northwest Research Extension Center, Colby, KS. Stahlman is a Weed Scientist with the KSU Agricultural Research Center in Hays, KS.

In 1999, they conducted the paired row planting trials using conventional till, dryland sunflower. An early preplant treatment of Roundup Ultra was applied at 28 oz/acre to remove early season weeds. The Pioneer 6338 hybrid was seeded on June 7. Spartan was applied preemergence at 3 and 3.2 oz of active ingredient per acre.

In 2000, the study was conducted on conventional till and irrigated plots, using Cargill SF260 seeded on June 1. Roundup Ultra was also applied in 2000 to help with early season weed control. They compared weed control using Spartan at 3 oz; Spartan at 1.5 oz plus Prowl at 1.24 lb; and Prowl alone at 1.24 lb. (Rates in active ingredient/acre.)

Both seasons, weed control as well as yield and quality of sunflower planted in 30” rows was compared to sunflower planted in 12” paired rows.

To achieve paired-row planting, two additional lift arm brackets with a six-inch offset were welded to the three-point assembly of a John Deere Max Emerge 7100 planter. The paired rows were obtained by planting the first series of rows, then returning on the same tractor tracks to plant the second series of rows for the pairs, Price explains. The paired rows are 12” apart, with an 18-inch inter-row space. The planter was set to plant at 12,000 seeds/acre for paired rows: two rows to match a single row planting rate of 24,000 seeds/acre.

Last year, they planted paired rows using a pull type planter and by sliding the tractor drawbar six inches to the left. The planter then pulled to the left of center of the tractor. The pairs were similarly achieved by planting the first series of rows down the field and subsequently returning on the same tractor tracks for the paired series. This method proved to be as effective in achieving paired rows without modifying the planter.

Sunflower yield both years was slightly higher in the paired rows compared to the single rows, but not significantly different. Crop quality was similar both years, regardless of row spacing and herbicide treatment.

Early preplant treatments of Spartan and Spartan plus Prowl controlled puncturevine better than preemergence treatments, although yields were not different between application timings.

Control of redroot pigweed ranged between 15% to 20% better in paired row sunflower compared to single row sunflower in 1999. Puncturevine control was about 5% to 10% better. Pigweed and puncturevine control was again better in paired row sunflower compared to 30” rows, though differences were less, perhaps due in part to dry field conditions, Price speculates.

“An advantage of the paired row concept is improvement in weed control, because the paired row sunflowers develop canopy closure 2 weeks earlier than the 30” rows,” he says.

Using paired rows, sunflower producers may be able to use the lower spectrum of recommended herbicide rates, without sacrificing weed control, Price points out. Further, the concept allows row crop producers to take advantage of earlier canopy closure, just as solid seeding does, without major equipment modifications or investment.—Tracy Sayler

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