A question I was asked by a number of dairy producers last October went something like this. "My silos and hay barns are full, but I have a great 4th cut in the field. It is really nice weather and I hate to see the crop go to waste. What happens if I leave it? Will it smother?"
My response to the last question was an emphatic NO. It will be fine. In fact, if you leave it alone you will guarantee yourself a terrific 1st cut.
Here's why. Root reserves are higher going into the winter. This leaves a healthy alfalfa plant that will grow more vigorously in the spring. Research has proven the increased hay yield during 1st cut, gained by healthier root reserves, more than compensates for the yield loss of not taking the last cut in the fall.
The picture below taken in 2010, is a striking example of cutting date differences in the same field. The alfalfa on the right side of the picture was given a longer rest than the alfalfa on the left side.
The next picture helps to explain why alfalfa is often healthier if left alone in the fall.
The alfalfa stems trap snow, providing insulation to the crown from sub-zero temperatures. The stems also act like snorkels which help the crown breathe and stay alive if trapped under ice. A healthy crown produces more buds, which lead to more stems, which lead to more yield.
The alfalfa plant will never suffocate because it's leaves dry up and fall off, leaving the stem erect.
Red clover, on the other hand will tend to suffocate more because it hangs onto it's leaves and the stems fold up like a cheap suit.
Three cheers for alfalfa.