The Earth’s rotation on its axis is cause for day and night. Its revolution around the sun is why we have seasons. Almost always, as a result of the tilt, either the Northern or Southern Hemisphere will be closest to the sun. However, there are two times of the year when the Earth’s axis is tilted neither toward nor away from the sun. One of these times is the autumnal equinox, which occurs between September 21 and 24, depending on the year.
It is at this time that the length of day and night are about equal in the Northern and Southern Hemispheres. During the equinox, the sun rises due east and sets due west when viewed from the equator. As for the rest of the world, the sun’s rays are neither at their closest nor farthest from landfall. In other words, temperatures are moderate with winter approaching in the Northern Hemisphere and summer on its way below the equator.
It’s the period on both sides of the now approaching autumnal equinox that we call fall, although it doesn’t officially begin until the equinox. At this time, most of our warm-season grasses have rounded the final turn and are headed down the growing season’s home stretch. It’s also a time when many cool-season grasses act as if they’ve guzzled a few Red Bulls and accept an extra dose of high forage quality — compliments of Mother Nature.
Fall often brings the desired combo of sunshine and cooler temperatures. This helps promote plant photosynthesis and the buildup of nonstructural carbohydrates while minimizing nighttime plant respiration and the breakdown of those same sugars. The cooler temperatures also have a positive impact on fiber digestibility. In short, fall-grown forage is cattle candy that easily translates into more gain and milk. The rapid decline in forage quality with advancing plant maturity is largely mitigated in the fall. Late fall-harvested alfalfa proves this point.
There are several ways to capitalize on the fall forage advantage. Fall stockpiling grass pastures has changed the landscape of grazing operations from north to south and extended the grazing season by as much as 40 to 60 days on some farms. Tall fescue excels as a fall-stockpiled forage, but many other cool-season grasses and even bermudagrass also perform well in such a system.
Fall-stockpiled forage allows for grazing deep into the late fall and early winter, saving dramatically on stored feed resources. Strip-grazing the fall-grown forage drastically improves utilization percentage and grazing days. If you graze cattle and don’t have a stockpiling plan, you’re missing out on a valuable and profitable strategy.
Another popular fall forage opportunity now being used involves the seeding of oats during late summer. Don’t think of late summer-sown oats in the same way you think of spring-sown oats. They’re two different forages when cut or grazed before the boot stage. Whereas spring-sown oats begin under cool conditions and finish under warm temperatures, it’s just the opposite for late summer-sown oats, which grow through the fall and are high in sugars but low in fiber.
Ryegrass also flourishes when seeded in the fall. In the South, it often provides the backbone of spring grazing, being fall interseeded into warm-season grass pastures. If seeded into a clean-tilled field, ryegrass can be planted earlier in the fall and used for late fall or early winter grazing. In the spring, ryegrass can either be grazed or cut and harvested as baleage.
Finally, there is the seeding of winter annuals in the fall. Although these don’t usually offer fall forage per se, the need for an adequate fall growth period to maximize yields during the next spring is well documented. Winter rye and triticale are the popular choices for spring forage, although other options are available, especially in the South.
Don’t cash in your 2022 forage chips just because September is approaching. There’s still ample opportunity to take advantage of fall’s sunshine, cool temperatures, and moisture to keep cattle grazing or fill storage structures. Enjoy this year’s autumnal equinox on September 22, knowing that the forage-growing season is still alive and well.
This article appeared in the August/September 2022 issue of Hay & Forage Grower on page 4.
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