Back to basics for alfalfa establishment

Joe Brummer, Colorado State University associate professor and Extension forage specialist, said those who grow alfalfa need to get it right the first time when putting alfalfa in the ground. Brummer spoke at Farmer U in Mulvane, Kansas, Aug. 18.

“Your input costs keep going up every year,” he said. “We want to get a good stand from the get go.”

Establishing a strong stand of a perennial forage like alfalfa is a little bit different than a crop like corn or wheat and some annual crops as they have a bigger seed. The bigger seed has more stored energy and can come up from deep depths. Alfalfa seeds are very small, Brummer said, with about 200,000 to 220,000 seeds in a pound.

“That’s definitely not the smallest, but it is a fairly small seed,” he said. “It doesn’t have a whole lot of stored energy.”

With that in mind how does one establish a thick, desirable stand? Brummer said each operation is different, many have expectations when it comes to the alfalfa stand. Do they want it there for three to five years? Or do they expect it to be there for 20 years?

“Again, it kind of depends on what you’re growing for and what your objectives are,” he said.

Before planting any seed in the ground considerations should include: proper seedbed preparation, weed control, seeding rate, seeding depth, timing of seeding, irrigation management, among others.

When it comes to seedbed preparation, weed control should come first.

“You’re always going to have weeds,” he said.

No matter the method of control—mechanical or chemical—you’re always going to need something to get rid of weeds.

“If you have some of these perennial noxious type weeds—bind weed, Canada thistle—some of those are extremely hard (to get rid of),” Brummer said.

If there’s a field a producer is planning on seeding to alfalfa and it has bindweed, consider getting a handle on it years in advance.

“Take care of it now and not wait to get the seed in the ground,” Brummer said.

When using herbicides for weed control, Brummer said to read the labels and make sure residual carryover isn’t going to be a problem with other crops.

“Make sure you keep good records so that you know what was applied in those particular fields where alfalfa’s going to go,” he said. “To make sure you’re not going have any carryover impacts.”

Another consideration before preparing the seedbed is to consider irrigation. Make sure fields are leveled, furrows are set ahead of time and pipe is put out and checked before flooding the field in those areas where flood irrigation is used.

“If you’ve got a sprinkler type system, making sure it’s in good operating condition as best you can,” he said.

Then it comes to variety selection. Brummer cautioned to stay away from older varieties—the Rangers and Vernals. He’s quit doing alfalfa variety trials in Colorado and found that despite all the work cutting, collecting data every 30 days, the work was for not.

Sign up for HPJ Insights

Our weekly newsletter delivers the latest news straight to your inbox including breaking news, our exclusive columns and much more.

“Everything tallied up at the end, 80% of the varieties don’t show any significant difference in yield,” he said. “Obviously pick a good variety.”

Rely on information from universities to make variety choices, but the work has been put in on the back end of the new varieties.

“Most of the newer varieties are going to yield well, and have good quality,” Brummer said. “More important things to kind of pay attention to are resistance to weed and insects or nematodes you might have in your area. You want to know what your pests and disease pressures are. Most of the new varieties have a good resistance package with them but I think there are some differences.”

If there is a specific pest or something to a certain area, make sure you cover that with the alfalfa variety chosen. Brummer warned that even though a variety has high resistance to a certain thing, that only means 50% or more of the plants are resistant to it.

“50% could be non-resistant,” he said. “It’s just the way that alfalfa genetics go.”

Another important thing to look at is fall dormancy. This is how soon the alfalfa is going to want to start to shut down in the fall. For northern Kansas, Brummer suggests fall dormancies at three or four ratings.

“I always like to think of fall dormancy, in a general way, as that’s about the number of cuttings of alfalfa that you can get based on length of your growing season,” he said. “If your growing season’s long enough for four cuttings, fall on four.”

Areas like southern Kansas are a little warmer with a little longer growing season that could get maybe four or five cuttings. While in southeast Colorado there could possibly be five cuttings depending on the growing season.

Brummer said to also look at the winter hardiness or fall dormancy. Through genetic selection and breeding they were able to separate the two traits.

“The lower the rating, the higher the winter hardiness,” he said. “So for Kansas, I think probably one, twos and threes is what you would want. Northern Kansas probably something in that two radius.”

As far as technology built into the alfalfa variety, Brummer suggests using varieties that are Roundup Ready. The low-lignin varieties are important too. Some are even stacked with “all the technologies.”

“So a lot of times you’re paying $6 a bag or a pound or $300 bags for just the technology that’s in that bag,” he said. “So, you have to decide whether you can recoup that later on down the road, whatever you’re doing with that alfalfa.”

Prior to planting, check the soil fertility. Alfalfa grows best in well-drained soils and it doesn’t like to have wet roots. It also likes a neutral pH of 6.5 to 7.5.

“If you have acidic soils, maybe adding some lime would be advantageous especially when you get down below that 6.2 to 6.3 or upper five,” Brummer said.

Past five, you’ll want to try and bring that pH up closer to 6.8 if you can.

Nitrogen generally isn’t much of a concern with alfalfa, but phosphorus and potassium is something that needs to be monitored, especially at the time of seeding as the plant is going to draw it out of the soil getting established.

“Alfalfa’s a big user of both P and K,” he said. “If you’re low, you’ll want to add either one of these prior to seeding if possible and incorporate. Both of these are fairly slow to move into the soil or not highly mobile elements so add some tillage to incorporate those in that top 3, 4, 5, 6 inches of the soil.”

Root growth is helped by phosphorus, and it aids in stem maturity. Potassium is needed to get vigorous stands and really promotes hardiness and stand longevity or persistence of the alfalfa. Look closely at soil tests and recommendations when it comes to P and K, Brummer said.

“Even though that soil came back testing high, it was still an advantage putting that P underneath that seed and letting that root to grow into,” he said. “And to me it really illustrates the impact it can have on your growth and vigor, getting these plants up and going initially is the key.”

The final prep of the seedbed is something that really needs a lot of attention before seeding. Make sure it’s smooth, firm and free of large clods.

“You don’t want it to be powdery or fluffy,” he said. “We have a very small seed, it can’t get it buried too deep.”

If the alfalfa seed gets too deep, it’s not going to make it to the surface.

“So the general rule of thumb is that you want it really firm,” Brummer said. “Walk across it; maybe your boot prints go in maybe a quarter to three-eighths of an inch. To me the firmer, the better. In my experience over the years.”

Kylene Scott can be reached at 620-227-1804 or [email protected].