No-Till Reduces Risk of Summer Seeding

By Jane Fyksen Crops Editor
Thursday, August 7, 2008 9:28 AM CDT

The window’s open for a summer seeding n but not for long. No-till improves chances of having enough moisture for success.

Weed control can be a major hurdle with spring seeding; weeds compete for nutrients and moisture. Summer seeding may actually improve the chance of achieving a productive stand, says Will Yliniemi, University of Minnesota Extension Educator in Hubbard and Becker counties.

Apply lime, if needed, incorporated to a depth of 4 to 6 inches. Lime improves nodulation, Yliniemi reminds.

“The price of fertilizer may make some producers hesitate…but nutrient levels must be adequate to establish good stands and yields. Broadcast the suggested rate of phosphate and/or potash and incorporate before seeding,” says Yliniemi. The pay-off of soil testing is getting bigger all the time.

Seed into a firm seedbed. “There is no logic in planting expensive seed at depths that will not emerge,” he says.

Paul Peterson, University of Minnesota Extension forage specialist, agrees that summer seeding has many advantages over spring seeding, including notably less weed pressure. In fact, he thinks it’s the “optimum timing to seed legume-grass mixtures, which have limited herbicide options, and species with limited seedling vigor.”

Summer seeding also spreads out the planting workload. It allows perennial forages to get a jump on the growing season and produce at or near established stand production the following year. There’s forage out there to protect against erosion from fall through spring, too.

Alfalfa seedlings need 6 to 8 weeks of growth before first killing frost. The window for alfalfa applies to all legumes, reed canarygrass, and probably tall fescue, too, says Peterson. “It’s ‘summer,’ not fall seeding,” Peterson stresses. “Even ‘late summer’ seeding can be misleading,” lulling producers into thinking they have more time than they actually do.

Peterson says the importance of summer seeding date is highlighted in research from central Pennsylvania. Each day planting was delayed after Aug. 1, total DM yield the year after seeding declined 160 pounds per acre for alfalfa, 110 pounds for red clover, 80 pounds for birdsfoot trefoil, and 120 pounds for reed canarygrass. After mid-August, orchardgrass yield declined 90 pounds for each day planting was delayed.

Conversely, perennial ryegrass yields the year after seeding increased one ton per acre by delaying seeding from early to late August. However, planting perennial ryegrass after late August resulted in 130-pounds-per-acre decreases per day seeding was delayed. Perennial ryegrass seeded in early August that’s over six inches tall in fall should be mowed or grazed to improve its persistent since shading reduces its tiller survival, says Peterson.

With a firm and moist seedbed, summer-seeded alfalfa has the potential to establish rapidly. When grasses are mixed with alfalfa, relatively heavier grass rates should be used with summer seeding when the grasses are relatively less competitive seedlings than alfalfa.

Maximize seed/soil contact. “Some classic Minnesota research from the 1950s compared various combinations of rolling and harrowing before and after drilled versus broadcast summer seeding of a mixture of alfalfa, red clover, and timothy. They concluded that best stands were obtained with rolling, drilling, and then rolling again. Rolling before seeding prevents drilling too deeply. They found that rain shortly after seeding favored broadcast seeding, while drought favored drilled seeding,” Peterson notes.

Firmness and good seed-to-soil contact are essential,” he reemphasizes. “Minimize the amount of tillage before summer seeding to avoid unnecessary soil moisture loss. A loose, fluffy seedbed severely reduces germination success. Multiple passes with a roller seeder may be required to get adequate firmness,” Peterson remarks.

Summer seeding depth should be about a half-inch, and somewhat deeper on sandy soil for most legumes. Orchardgrass is particularly sensitive to being seeded too deeply, however. In sand, all species establish equally well at one-half or one-inch seeding depths.

“Perhaps the best way to provide a firm seedbed and favorable soil moisture is by no-till seeding,” Peterson advises. Four years of no-till research on a clay soil in Virginia demonstrated the merits of the no-till approach. They consistently achieved successful establishment and winter survival by no-tilling 15 pounds of alfalfa per acre one inch deep up to three weeks later than broadcast seeding with a cultipacker seeder in a prepared seedbed.

They attributed the ‘no-till advantage’ to: Consistently more rapid emergence of no-tilled seedlings (broadcast seedlings often required 3 or more weeks to emerge when moisture was limiting); greater root development under no-till due to less temperature extremes and in particular higher minimum soil temperatures in the root zone later into the fall; and less heaving loss with no-till.

In Wisconsin, the potential to no-till seed up to three weeks later than seeding into a tilled seedbed may be a stretch; a 10 to 14-day later window for no-till seeding of alfalfa and other legumes, reed canarygrass and tall fescue may be a safer bet. There’s even later leeway for no-tilled smooth bromegrass, orchardgrass and timothy. In a sandy loam at Mandan, N.D., both Aug. 15 and Sept. 4 no-till seedings of eight pounds per acre of smooth bromegrass one-half-inch deep into wheat stubble resulted in successful establishment in three of three years tried.

“So, if timing and seedbed management are right, summer can be a great time to get dense, productive perennial forage stands established,” Peterson concludes, stressing that no-till drilling ensures the most favorable moisture and temperature environment for rapid germination and seedling development before winter.

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