Sliding into the second seeding season

By Mike Rankin

As we rocket past the middle of July and become entrenched in the dog days of summer, let’s not forget that
the second forage seeding season will soon commence. Some planning is in order.

Although spring marks the traditional and most common time to break out the forage drill, late summer and fall provides for a unique growing environment that is beneficial for generating high-quality forage. If at least some warm and sunny days are accompanied by adequate rainfall or irrigation, excellent yields also come with the deal.

Depending on where you hang your hat, mid-July to mid-September marks a prime time for seeding annuals to provide harvested feed later this fall, to extend grazing opportunities later into the fall and winter, or to establish perennial legumes and grasses for future production. Extending seeding dates a bit longer opens the option to establish winter annuals such as rye, wheat, or triticale for harvest or grazing next spring.

Spring cereals

In the past five years, there has been a resurgence in the number of dairy and livestock producers who have found the magic of fall-grown spring oats (or in some cases triticale). Additionally, multiple university researchers have recently evaluated different combinations of varieties, planting dates, and harvest timing. This has occurred from the Northeast to the West.

Late summer-sown oats are not the same forage as spring-sown oats. Whereas spring-sown oats begin under cool conditions and finish under warm temperatures, it's just the opposite for late summer-sown oats. Oats harvested or grazed in the fall have significantly lower fiber levels, copious amounts of water-soluble sugars, and high levels of total digestible nutrients.

Given about 75 days to germinate and grow, oats will yield 2 to 3 tons of dry matter per acre. Nitrogen is needed to ensure high yields and forage quality. Oats grown on nitrogen-deficient soils will be a disappointment. In most cases, 40 to 60 pounds of nitrogen per acre are needed unless manure is applied prior to seeding or you know there will be carryover nitrogen available from a previous crop. Discuss specific recommendations with your county or state extension specialists.

Winter annuals

As with fall-seeded spring cereal grains, the utilization of winter annuals such as cereal rye have also seen a rise in popularity as a forage resource. Here, the planting date is extended later into the fall as the needed establishment period is much shorter. There are both Southern and Northern types of winter rye.

Cereal rye is extremely winterhardy (Northern types) and generally gets out of the starting gate early in the spring. It can be utilized for spring grazing or left to grow and be machine harvested. Dry matter yields of rye can be over 3 tons per acre depending on harvest maturity. The downside of harvesting winter cereals in the spring is that planting of a subsequent crop is often delayed, especially in northern regions. Rye also has an extensive root system that will deplete available soil moisture for the next crop during a dry spring.

Perennials

Alfalfa and cool-season grasses can both be established in late summer or early fall; in some parts of the U.S., it’s the preferred establishment period. Perennial grasses will need a bit more time to establish an adequate root system, so cheating on the backside of the recommended seeding window is more risky than with alfalfa. In either case, lack of adequate moisture is almost always the primary reason for seeding failures. Time your seedings based on the weather forecast; a bad forecast for cutting hay is a good forecast for making late-summer or fall seedings.

In 2016, there were a number of failed alfalfa spring seedings. If you’ve determined that there’s simply no hope of stand resurrection, alfalfa can be reseeded into these same fields without risk of autotoxicity. This is not the case with one year or older established stands. Scott Wells, University of Minnesota cropping systems and forage specialist, reinforced this point in a recent blog post.

Late-summer alfalfa seedings rarely have issues with seedling diseases because of the drier and warmer conditions. There are also other advantages, including fewer potential weed and insect issues. The near equivalent of an established stand yield is usually realized in the year following a late summer seeding.

Seeding dates will depend on location, but a general rule of thumb is six to nine weeks before the first killing frost. Five weeks is usually the point where you’ll want to keep seed in the bag. As a general rule, recommended seeding and fertility practices for spring seedings apply to late-summer seedings. It is worth mentioning that a firm seedbed to optimize seed-to-soil contact is especially important with late-summer seedings.

Plan now

Seeding during the “second season” can bolster forage supplies, extend the grazing season, reduce the amount of stored feed that needs to be fed during winter, and provides excellent quality forage. In the case of perennial legumes and grasses, seeding in late summer can result in full productive stands the following year. A number of species and variety options exist, so start the planning process now if you haven’t already done so.