If you have perfect, well-drained soils, pure alfalfa is still the queen of hay-crop forage.
If not, consider mixing in a grass species to improve yield, suppress weeds and maintain hay stands a year longer, recommends Ev Thomas, an agronomist with Miner Institute in Chazy, N.Y.
"Eighty percent to 85% of New York forage is now an alfalfa/grass blend, and that percentage is even higher in New England,” he says.
Variable soil types with-in fields in the northeastern U.S. make alfalfa/grass blends more competitive than pure stands of either alfalfa or grass. Variable soil types are also common in many other dairy areas, particularly in the Midwest.
"Species will adapt to microsoil environments within fields, with alfalfa competing well on well-drained soils and grasses doing well in low spots,” Thomas says.
If you seed
an alfalfa/grass mixture, you also have to take into account the ability of grass species to tolerate intense harvest management when you match up grass and alfalfa maturity rates.
Bromegrass has less persistence under intensive harvest management than other species. And while timothy does well in spring and fall, it goes into semidormancy during the hot-weather months.
"Reed canarygrass is a high-yielding, persistent species with an almost insatiable appetite for manure,” Thomas says. But it is difficult to establish, is less frost-tolerant and doesn't tolerate close mowing [2" height] in the seeding year. Plus, it loses quality quickly—with lower quality even at the late boot stage compared to tall fescue.
"Tall fescue is easier to establish than reed canarygrass, and does well in somewhat poorly soils,” Thomas says. But it is not well-suited to droughty soils.
"The newer varieties of tall fescue are endophyte-free and appear to fit well in modern dairy rations,” he says.
There are also large differences in the rates that grass species mature. In Central New York, for example, there can be a three- to five-week difference in heading dates between orchardgrass and timothy.
"But there can also be huge differences in maturity within some, but not all, species,” Thomas says. He therefore recommends selecting your grass species first, and then selecting the best-maturing varieties within that species to match up with your alfalfa-cutting schedule.
also differs with alfalfa and grass. Alfalfa establishes deep taproots and is able to pull nutrients from deeper soil profiles.
"Grasses are much more efficient in nutrient uptake from the plow layer. That can be a plus or a minus,” Thomas says. For example, grasses are highly efficient in the uptake of potassium. "Grasses will thrive and contain 2.5% potassium at soil
potassium levels low enough to starve alfalfa,” Thomas says.
"If you're starting out with low fertility, it is difficult to start an alfalfa/grass mixture because the grass sucks up all the potassium,” he says.
at Cornell University also show that grass, at one-third, two-thirds or all-grass forage, won't sacrifice milk yield. In fact, dry matter intake and milk production actually increased when more grass was included in the ration. Milk urea
nitrogen levels also declined with grass inclusion, suggesting that less nitrogen was being excreted.
Managing Alfalfa-Grass and Grass Silage for High Producing Dairy Cows