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April 7, 2005 Stand Establishment is Important Step in Grain Production Maximum grain yields almost always begin with quick emergence and uniform stands, according to North Dakota State University Extension Service agricultural engineer Vern Hofman. “Planting seed at a uniform depth in moist soil is an essential first step toward a uniform stand of grain that is vigorous and highly competitive,” he says. He also recommends that if a grain crop is going to produce its best, producers must provide fertilizer in adequate amounts and close to the seed. Fertilizer placed with seed must be limited, so it needs to be side-banded or banded mid-row when added at planting time. If producers use anhydrous ammonia at seeding time, it must be at least 3 inches from the seed. Adding fertilizer during the growing season is an option, but producers must apply it in a timely fashion and before a rainfall, which will carry it to the plant root system. The best planting depth for small grains is about 1½ inches, Hofman says. Planting that close to the soil surface is desirable for quick emergence, and to establish a stand to compete against weeds. Direct seeding allows seed placement in moist soil, so if dry weather occurs, roots will be established in moist soil even though soil near the surface may dry out. Planting deeper than 2 inches puts seed in cooler soil, increases the time for plants to emerge and gives weeds a head start. Planting at 3 inches or more reduces stands because many plants will not emerge. “A thick and uniform stand may be one of the best and most economical methods of controlling weeds,” Hofman says. However, a uniform seeding depth is difficult to maintain with older, double-disc press drills. These drills almost always require a pre-seeding tillage operation so they can penetrate the soil, and this further dries the soil. Producers should till no deeper than seeding depth, but that’s tough to do, he says. Double-disc press drills use spring down-pressure to push the opener into the soil. The only thing controlling the depth is the firmness of the soil. Press wheels are 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 and will help maintain uniform depth, but they seldom are used because they reduce clearance. Speed also affects planting depth. As speed increases, controlling seed depth with press drills becomes even more difficult. Faster speeds cause disc openers to be almost out of the soil part of the time when they bounce over clods, and to sink into the disc opener hub in soft soil. This causes considerable variation in seeding depth. A warm seedbed enhances seedling emergence. This may be a challenge in a no-till system where soil-conserving residue keeps the soil cooler, Hofman says. However, the seed opener on a drill disturbs the soil, which helps warm up the area where the seed is planted. Also, the uniform and shallow planting depth that new seeders provide helps reduce the effect of cool soils. Direct seeding in dry years may be the best method for establishing a good stand, since less soil disturbance occurs and saves as much moisture as possible. Newer equipment has solved many of the problems associated with seed placement. Proper depth control has been incorporated into machine designs. The best units for depth control, such as single-disc drills, have a gauge wheel directly alongside the opener, Hofman says. The next best unit has gauge wheels mounted behind the opener and connected to the opener framework. Some gauge wheels mounted in this configuration are small in diameter, narrow, and have difficulty maintaining proper depth because they sink into soft soil. A wider and larger diameter press wheel usually will provide better depth control for an even stand. Air seeders often contain load-carrying wheels in front of the seeder and press wheels behind to firm soil around seed. Some seeders, such as hoe drills, which usually have excellent residue clearance, are stretched out more than others for trash clearance, which causes them to lose some depth control. Some disc-type air seeders are designed with gauge wheels beside the disc opener, which helps them maintain excellent depth control. Other units have gauge wheels behind the opener. Newer air seeders have improved considerably in depth control, compared with units introduced 10 or 15 years ago. “Proper seed placement is the most important part of producing a profitable crop yield,” Hofman says. “If a poor stand occurs from poor emergence, usually very little can be done later in the season to overcome the problem.” ### Source: Vern
Hofman, (701) 231-7240, vhofman@ndsuext.nodak.edu |
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