Harvest Schedule for Well Established Alfalfa

Warren C. Thompson National Forage Specialist: America’s Alfalfa

If you really want to ‘open a can of worms’ try to answer this question to please every alfalfa grower in the USA! Some growers want quality, others want yield, others want persistence, and some growers don’t give a flip about persistence, all they want is a crop rotation system that fits their land and animal needs and produce as high quality hay as possible. Others want to graze and make hay from the same fields, others want it ALL! The question is, can you have your cake and eat it too?  

You can come closer to this today than you could have a decade or two ago when you use the more persistent fudge-proof varieties. Here, I am referring to the grazing and traffic tolerant varieties that are coming closer to ‘having it all’ than any other germ plasm we have used before.

As we have said before, the more often a crop of alfalfa is harvested the higher the feed quality. The protein is higher, as is digestibility; fiber is lower and animals make more gains and produce more milk than when the crops are harvested less frequently. 

Yet when alfalfa is harvested too often, yields drop and if continued, persistence will suffer as well.

Earlier lectures have dealt with the introduction of traffic/grazing tolerant varieties that we have developed over the years. This is THE starting place to get the most from your alfalfa fields. But be assured, they are not entirely ‘man-proof’ but they do persist with marginal management like you and I have never experienced before.

With these newer more disease, insect, and traffic resistant varieties, the recovery period after harvest and considering normal rainfall is something like 28-32 days as compared to 35-40 days for the older varieties such as Atlantic, Buffalo, and Vernal. This means that today’s growers can usually harvest the first cutting about a week to ten days earlier thus harvest one more cutting each year from varieties such as AmeriStand 403T and AmeriGraze 401+Z, AmeriGraze 201+Z, AmeriGraze 702, and AmeriGraze 701. By harvesting more frequently, hay and silage quality and yields are improved by as much as 15-20%.

In one of my earlier lectures, I discussed harvesting the highest quality alfalfa hay from the grazing/traffic tolerant varieties. I even suggested it is possible to harvest at 21day (three weeks) intervals without permanent damage to the stand. This will be fine if there is demand for the extremely high quality hay and you have a special market or use that will pay big bucks for it. But don’t make this a continuing practice unless you want to replace the field with another crop soon. A couple of harvests a year seems to be fine but continuing this fast pace harvest is bound to reduce the vigor of any alfalfa.

When harvesting on the 28-32 day schedule, one of the recommendations that still persists is to allow one crop (usually a low yielding one that is caught in a drought) to grow and extra week or two (or near maturity-full bloom). This will strengthen the root and crowns and build food reserves ‘drained’ from earlier more-frequent harvests. The negative, feed quality will be lower, protein levels can drop 13-15% and fiber is greatly elevated and volunteer consumption is reduced.

What about late fall harvest? Some years, it is such a temptation to harvest late fall regrowth especially when hay supplies are short and cash hay prices are sky-high. Research has shown and farmers have confirmed that the amount of hay removed within the 5-6 weeks period prior to historic freeze dates is extremely harsh on plant life. Also, hay yields from these harvested areas the following year will be reduced by the tonnage harvested the pervious fall. Those farmers who feel they must harvest this crop, we make two suggestions:

1) cut near the historic frost dates so that the alfalfa will not have time for regrowth. This is the part of harvest in the fall that really hurts the stand.

2) Wait to harvest until there are two consecutive nights of 24 degrees F to harvest after a couple of days for plant wilting (see photo).

When you do harvest, set the mower to leave extra crop stubble (especially in the northern states) to protect from ice sheet damage. The stubble also helps to prevent sheet, gully, and wind erosion in other parts of the country.

So the harvest system on year old or older alfalfa may be as simple as:

* Make the first cut at bud to early bloom.
* Subsequent cuts (depending on moisture) at or near four-week intervals with the last harvest 5-6 weeks ahead of the historic hard-freeze frost date.
* Should a fall harvest be made, wait until frost or just ahead of the historic frost date and leave tall stubble for crop and land protection.