To bloom or not to bloom?

By Kassidy Buse

A common recommendation of agronomists is to let one alfalfa cutting reach bloom each year.

Ev Thomas, retired agronomist from the Miner Research Institute in Chazy, N.Y., says otherwise in The William H Miner Agricultural Research Institute Farm Report.

“For many years, I’ve said that in managing alfalfa for dairy cows, you should never see an alfalfa blossom, from seeding to plowdown,” says Thomas.

Thomas also notes there’s room for difference of opinion due to no research supporting either opinion.

But, if one cutting is to bloom, which cutting should it be?

The first cut of alfalfa-grass typically contains the most grass. Grass, even the late-maturing species, is close to heading when alfalfa is in the late bud stage.

The second cut is exposed to long, hot June days that result in highly lignified, fine stems. A Miner Institute trial found that the stem quality of bud-stage second-cut alfalfa was no better than full-bloom first-cut alfalfa.

The third cut can be influenced by prior harvest management. If it was a late second cutting, the third cut was growing during midsummer heat. This cut would also have highly lignified stems.

The fourth cut often takes a long time to bloom, if it makes it there. A killing frost might arrive first.

For any cutting, the more grass in the stand, the lower the forage quality if alfalfa is left to bloom.

“The objective of letting alfalfa bloom is to improve root reserves, and therefore extend stand life,” says Thomas. “We need to balance the impact of delayed harvest on plant health with the economics of feeding alfalfa of lower quality that is needed by today’s high-producing dairy cows,” Thomas adds.

How alfalfa and alfalfa-grass is managed depends on if the goal in mind is long stand life or high milk production potential.

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