NORTHERN "AG" EXPOSURE

by Mark Miller
Rolette County Extension Agent

Crop Management Field School

A crop management field school will be offered on Thursday, June 21, from 8:30 a.m. to 5:15 p.m. at the North Dakota State University Carrington Research Extension Center. The targeted audience is crop advisers and farmers. The school is organized and conducted by the NDSU Extension Service.

The school will provide hands-on training on crop pest and soil management using field research and demonstration plots. Specific field sessions include weed identification, herbicide mode-of-action diagnosis, insect management (including aphids and lygus bug), small grain disease fungicide decision aids and application strategies, soil quality, and oilseed crop nitrogen management.Workshop instructors/hosts include Greg Endres, extension area agronomist; Leonard Francl, NDSU plant pathologist; Dave Franzen, extension soils specialist; Phil Glogoza, extension entomologist; Terry Gregoire, extension area agronomist; Bob Henson, NDSU research agronomist; Kirk Howatt, NDSU weed scientist; Alan Ness, National Resources Conservation Service agronomist; Jerry Schneider, extension crop scout; and Steve Sieler, NRCS soil scientist.

Uniform Planting Depth Is Critical to Grain Yield

Fast emergence and uniform stands are keys to peak grain yields. And starting off with seeds planted at a uniform depth is an essential first step toward a uniform stand, say North Dakota State University specialists. "Rapid uniform emergence ensures a vigorous, highly competitive stand. That plant vigor and uniformity carry right through to even maturity at harvest," says Duane Berglund, an agronomist with the NDSU Extension Service. "A uniform seeding depth is difficult to maintain with older double-disc press drills," notes Vern Hofman, an agricultural engineer with the NDSU Extension Service. "Newer equipment has solved many of these problems as depth control equipment has been incorporated into machine designs." That equipment allows producers to place seed more precisely at shallower depths, the specialists say. "In general the best planting depth for small grains is between 1 and 2 inches," Hofman says. "Planting that close to the soil surface is desirable for quick emergence and to establish a stand to compete against weeds, but a dry spell could dry out the soil and kill new seedlings." Planting deeper than 2 inches places seed in cooler soil and increases the time for plants to emerge. That gives weeds a head start, he says. In fact, a thick and uniform stand may be one of the best and most economical methods to control weeds. Berglund says shallow seeding gives seeds more access to oxygen. That's especially important if soils become saturated. The agronomist adds that it's important not to do unnecessary tillage which might dry out the seedbed. He notes that recent research in Manitoba indicates that relatively shallow seeding increases barley and wheat yields by more than 5 percent.

Berglund says other research indicates that hard red spring wheat and durum perform best when seeded at about 2 inches. Deeper seeding reduces stands, tillering and yield. Tall durum and hard red spring wheat varieties should not be seeded deeper than 2 to 3 inches. Semidwarf varieties should not be seeded deeper than 2 to 2 inches.  Ideally, seed should be placed in a moist, firm and warm seedbed, Hofman says. One problem in no-till systems is that soil-conserving residue also keeps the soil cooler. The shallow planting permitted by new planters helps reduce that effect, he says. Hofman notes that before the introduction of direct seeding  equipment, farmers had difficulty maintaining a uniform seeding depth. Seeders like the common double-disc press drills lacked good depth control. With those drills, spring down-pressure pushed the opener into the soil and the only thing controlling the depth was the firmness of the soil. The press wheels were designed to carry the weight of the drill and firm the soil over the seed, not control the depth of the disc openers. Depth bands are available for those drills that will help maintain depth, but they are seldom used because they reduce the residue clearance. Speed also affected planting depth. As speeds increase, it's even more difficult to control seed depth with older press drills. "Most new no-till or direct seed drills have excellent depth control built in," Hofman says. "The best units contain a gauge wheel directly alongside the opener, but may reduce trash clearance. The next best unit is gauge wheels mounted behind the opener and connected to the opener framework." Hofman notes that some gauge wheels mounted in this configuration are small in diameter and narrow. They sometimes have difficulty maintaining proper depth because they may sink into soft soil.

Air seeders usually contain load-carrying wheels in front of the seeder and press wheels behind. Some are stretched out more than others for trash clearance which causes them to lose some depth control, he says. Greater distances between seed points and gauge wheels may reduce depth control accuracy.Newer air seeders have improved considerably in depth control compared to units that were introduced about 15 to 20 years ago, he says.

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