Seed & Feed

Published on Fri, 02/12/2010 - 12:45pm

Dairymen are looking forward to 2008, according to Dr. Dan Undersander. The University of Wisconsin-Madison Agronomy Professor and Extension Forage Specialist says although there is a lot of concern over high input costs, the high prices for all of the commodities, the grains and the hays and the milk, are causing a level of optimism that we haven't seen in a long time. The high price of hay means it's crucial for producers to maintain their forage stands - and that means turning over alfalfa after no more than three years.

Even though varieties are exhibiting higher levels of disease resistance and, in some cases, better yield potential, Undersander says, "We just can't expect a stand to last forever. When we are harvesting an alfalfa field at the bud stage, we're putting stress on it, we're weakening that stand."

 

 Producers, he says, can't afford to grow low yielding crops and they aren't saving any money on production costs by doing so. In addition, producers should "take the legume credits more often. Nitrogen being 60 or 70 cents a pound now, that's worth quite a bit for a corn crop."

 

Even if the stand is less than three years old, weather, grazing pressure and other factors can cause a stand to grow old before its time. Undersander says producers should begin monitoring their alfalfa as it greens up, and then count shoots.

 

"We would be thinking about roughly 50 stems per square foot as being what we would want to have optimum yield," he says. If the count is below that, he suggests digging up a few plants to inspect them for signs of crown rot.

 

"If the crowns are over 50 percent rotted," he says, "then we should dig up that stand, because it will be a reduced yielding stand - we should replant somewhere else."

 

A New Field

As the producer is preparing to seed a new field, the first thing Undersander recommends is that it be a field that's been out of alfalfa for at least a year, due to the auto-toxicity.

 

"If you plant sooner," he says, "you might get a stand but it will never yield as well, even years after establishment."

 

And, he says, the field should be level. "We can use reduced till. I don't usually think about no-till too much, because we oftentimes would need to disk a corn or a soybean field to level it, so that we can make hay across it. That might be a good time to include phosphorus and/or lime, if it's needed."

 

When it comes time to drill, he says, pay close attention to seed placement. It should be between a quarter and a half inch deep, and the soil around the seed should be firmed.

 

"If we have a loose soil," says Undersander, "then the water can't transfer to the seed, and we don't get good establishment. And that's particularly critical because of our shallow seedings. We want to use a drill with press wheels, or something like a cultipacker."

 

Controlling Disease

Alfalfa producers have no practical means of controlling plant diseases other than seed treatments, which can ward off soil-born fungal diseases like Phytophthora and Pythium. Apron is the seed treatment of choice.

 

Producers in susceptible areas should also select disease-resistant varieties, but in high rainfall areas, says Undersander, "diseases will overcome, and that's why we need to turn over stands periodically."

 

In addition, it's important to make sure weeds are controlled during the first 60 days following establishment. Undersander says this is the period during which a weed infestation can reduce the population of the stand.

 

"And if the plant population of alfalfa is reduced," he says, "it can never recover."

 

Producers can only use an herbicide for stand establishment if they're planting pure alfalfa; if there are legumes in the mix, there's no available weed control package. Undersander says a lot of farmers used to use cover crops on their alfalfa stands, but that figure is down to 30 percent, with most of them in the north, where the alfalfa comes on faster and the weed pressure is reduced. Further south, producers are more likely to apply an herbicide.

 

Herbicide Tolerant Alfalfa

And many of those producers in particular, he says, would like to be able to use the new herbicide-tolerant alfalfa developed by Monsanto Co. Like Monsanto's Roundup Ready corn, wheat and cotton the forage is genetically engineered so it can be sprayed with the all-purpose weed and grass killer glyphosate.

 

However, last year a federal judge placed a hold on further plantings of the biotech alfalfa, pending completion of an Environmental Impact statement. USDA's Animal and Plant Health Inspection Service, which deregulated the biotech alfalfa in 2005, has begun seeking public comment on its plan to study the potential impact of the forage crop.

 

"Those people who have used herbicide," says Undersander, "are very interested in it, and feel that it is a loss to the program not to be able to have it. I look at the Roundup Ready alfalfa, and I think the farmers I'm talking with, as another tool in the box."

 

There are limits to how much legume can be mixed in with an alfalfa stand. Undersander says the standard, for farmers growing forage for themselves or for the equine industry is about 30 percent, and about 30 to 40 percent of dairymen are doing so.

 

"It makes the alfalfa a little bit more palatable," he says, "gives them a little bit less risk of heaving, and less risk of winter injury."

 

Producers growing commercial hay, of course, go with 100 percent alfalfa stands.

 

How long should a producer wait before turning cows out on a new stand? Undersander says there may be merit to the argument for holding off on grazing until after the first cutting, but he believes the most important thing is to make sure the plants are big enough that cattle cannot pull them out of the soil.

 

"That will depend a little bit on their soil type," he says, "and the amount of forage available. But I would say that it is best to help get the plants established. If we let it go up into the early flower stage to get a good root system, to get good root carbohydrates, then we can begin either making a hay crop, or grazing as we want to the rest of that seeding year."

 

Growing Organic

There is also tremendous opportunity for producers of organically raised alfalfa, either as part of an organic dairy herd or for marketing to this rapidly expanding sector of the industry.

 

Undersander says producers seeking to go organic need to select varieties with a high level of disease resistance. In some areas, they should also look for varieties with natural resistance to potato leafhoppers.

 

Alfalfa has high potassium requirements, so organic producers need to either establish stands in soil with high K levels, or bring the nutrient in from another source. Soil pH can be adjusted if necessary; lime can be applied in an organic situation.

 

"We oftentimes mix the grass if we're going towards an organic situation," he adds, "and that can work well."

 

Winter Weather

The question this coming year in the Upper Midwest will be the impact of what has been so far a mild and moist winter. Undersander says growers have been surprised to find so little frost in the ground. Instead of running off, the snowmelt and rain are soaking in, and there's little ponding and icing. Without a good snow cover, the alfalfa crop risks winterkill. But so far, the conditions have been beneficial for forage producers.

 

"A lot of the region was kind of dry going into the winter," he says, "and we need good moisture in that root zone for the spring green-up during March or April, depending on where we are, north to south. And if we don't get the moisture early, then that alfalfa doesn't grow as well, and first cutting yields are much lower."

 

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