Dairy producers should be out standing in their fields.
Dr. Dan Undersander, University of Wisconsin professor of agronomy, encourages all dairy forage growers to assess their alfalfa and hay fields. “Looking at the fields, we didn’t replant as many stands from last year as we should have. We’ve got a lot of thin stands and that’s hurting us in terms of yield and production this year,” he observed during the first segment of “Cropping For Forage Rewards”, a three-part World Class Webinar being presented by Professional Dairy Producers of Wisconsin.
Determine if a stand is thick enough to keep by counting stems, not the number of plants. “Stems are the key thing. You need 55 or more cut stems per square foot for maximum yield. If there are less than 55, you don’t have a good enough stand for high yields,” Undersander said, citing abundant research on the issue.
In a good field, the count will be closer to 100.
“If you don’t have 55 stems per square foot, recognize that you just don’t have a good enough stand for high yields,” Undersander said. “It’s a little bit like planting corn at 20,000 plants per acre. You’re not going to get the yield you would with 30,000 plants per acre.”
Dandelions in a field often means the stand is thinning. It won’t do much good to spray, Undersander noted. Unlike grain, where controlling weeds sets the stage for higher yields, controlling weeds in forage might actually decrease yields a bit.
Cut weedy fields early, Undersander advised, noting the main problem with yellow rocket and dandelions is the wide variation in drying times. “That’s less of a problem with haylage, but a terrible problem with hay making.”
University of Wisconsin Extension offers a publication, A 3620, with root health assessment pictures to help make the decision on keeping or flipping a stand.
Thickening an alfalfa stand
Interseeding alfalfa into a field with less than 55 stems per square foot is a problem because of autotoxicity, wherein established plants give off a compound that inhibits germination and growth of other seedlings.
Alfalfa autotoxicity prevents interseeding, Undersander stressed. “We do not recommend it if stands have been out there a year or more. Interseeding absolutely does not work with alfalfa into an existing alfalfa stand. The plants do come up, but they are puny, they don’t compete against the big plants and they eventually die off.”
However, if the field is one year old or less, it does not usually have autotoxicity and can be interseeded. For instance, if a poor stand came of a field seeded last spring, a grower could have interseeded last fall or this spring.
It’s a different story for fields that got a poor start this year. “If you seeded this spring and got a poor stand, you might think about interseeding this fall, but I frankly usually don’t recommend it,” Undersander said.
In his experience, those who go this route will get a few more plants and increase yields a bit, but the field will never be as good as if they’d started over. “My recommendation for those of you that seeded this spring and didn’t get a good stand is simply disk it once this fall, reseed and start over,” he said.
Interseeding can work
Interseeding with red clover is another option. It works well to thicken stands and increase yields. It can be interseeded at 6 to 8 pounds per acre with a grain drill in early spring or fall, establishes well and makes a good quality forage if harvested early enough.
The downside to red clover is it has a slower drying rate than alfalfa, making it difficult to bale. “Most of us don’t interseed red clover when making hay, but it is a good haylage crop and I do think it’s underutilized,” Undersander pointed out.
Interseeding with grass is another way to go, but Undersander is not very positive because studies show it seldom improves yield. “The way I look at it, if you feel you have to do something, pick a cheap fescue. It won’t do much, but it will make you feel better,” he said.
Sometimes, an alfalfa/grass mix is desirable. For instance, it can be used on heavy soils where alfalfa drowns out in the low spots, on heavier soils where heaving is likely to occur in the spring, and in dairy rations to reduce non fiber carbohydrates when a lot of corn silage is used.
From an agronomic standpoint, incorporating some grass into dairy rations makes sense because it can improve yields of seeding year stands. Grass dries a little better than alfalfa, is at less risk of winterkill and offers manure management options.
From a nutritional standpoint, grass legume mixtures offer higher total fiber than alfalfa, and a higher proportion of digestible fiber than alfalfa or corn silage.
There is a place for alfalfa/grass mixtures, Undersander said, but understand there is not much difference in yield. “If you can benefit from incorporating some grass into your alfalfa stands, then do it, but if the need and conditions do not exist, it is a lot easier to grow solo seated alfalfa,” he observed.
Growers need to select grasses carefully for late maturity, good seasonal distribution of yield and disease resistance, especially to rust.
When seeding alfalfa/grass mixtures, aim for 30 to 40 percent grass as a percentage of dry matter. For every 10 pounds of alfalfa, Undersander recommended four pounds of orchardgrass or 6 pounds of tall fescue or 6 pounds of meadow fescue.
Bear in mind that interseeding grass into thin alfalfa fields seldom increases yields. Ryegrass responds quickly, but does not grow in summer heat or drought, while orchardgrass and tall fescue take 90 days to begin producing yield. Brome grass and timothy take even longer.
“I’m going to suggest that if the stand was thick enough that you were considering interseeding, it was maybe thin enough that you should take it out and reseed,” Undersander said. “I hate to be negative, but there isn’t too much you can do about a thin stand other than turn it over.”
Consider the rotation benefits, which include an extra 15 to 20 bushels of corn. Instead of keeping a low yielding field, plant something and get higher corn yields.
“The overall message here is interseeding into a thin alfalfa stand really doesn’t work,” Undersander said. “A lot of people think you’ve done some good, but you’re not going to see a yield advantage. We’ve got year after year of trial showing that.”
Harvesting quality forage
A major factor affecting the forage quality of harvested alfalfa is the growing environment.
Research shows digestible fiber is higher when the growing weather of the crop is cool, Undersander pointed out. That’s why first cutting is nearly always higher in digestible fiber than later cuttings and why California dairy producers have long preferred to buy high mountain valley hay from Utah and Colorado, rather than forage grown in their hotter climate. “So if you do need to buy, consider buying hay from the north, like Manitoba, compared to regions to our south,” he suggested.
In grasses, the leaf digestibility is very high in the vegetative stages and falls during flowering and seed. “We see the same thing in alfalfa,” Undersander said. The leaves don’t change much in digestibility as the alfalfa matures, but the more mature the alfalfa, the more stem there is. Compared to leaves, stems are lower in quality and decline more rapidly.
That’s why recommendations are now to cut alfalfa by the height of the plant and not worry about whether it is in bud or not, Undersander said. “Alfalfa at 29 inches in height is dairy quality. After that, you’re just putting out more stem,” he explained.
Disease can increase leaf loss. Fiber digestibility is often low through spring due to leaf drop from cool conditions and/or disease, Undersander said, which has prompted interest in fungicides to reduce leaf diseases and leaf drop.
Growers on the East Coast, in particular, have found fungicides to be a benefit. “The problem is, it must be applied before disease occurs and it doesn’t last, but if you get it right, it works,” Undersander said.
First cutting has the greatest potential for positive response for fungicides, which cost around $25-$30 per acre. “I would never recommend it when hay was cheaper, but now with hay between $200 and $300 a ton, it can pay off handsomely,” Undersander noted.
He also strongly recommended the use of roller conditioners, wide swaths for drying and paying close attention to raking, tedding and merging. Always harvest in ways that preserve as many leaves as possible.