If you would actually watch some of the info. posted you would have at least one researchers point of view on that.
Biggest unknown determining factor in this area on number of alfalfa cuttings per year is temperature, second largest is water availability.
Another big factor that is easily controlled is percentage of bloom stage at cutting . Alfalfa cuttings for dairy hay is always cut prebloom. Beef and other alfalfa is cut anywhere from 10 precent bloom on up to almost completely bloomed.
Alfalfa cuttings for dairy hay will almost always get an additional cutting on the same ground as hay cut for beef cattle.
Decision of sacrificing tdn for more total volume /tons.
The plant species that you're dealing with also affects it's ability to recover after cutting. Alfalfa is a "tap root" type of plant, deeper root, so it can recover more easily during drought conditions than a shorter rooted species like many/most grasses. However, I still believe that the underlying PRINCIPLES remain.
Here in the upper midwest, and having grown up dairying, it's common to cut alfalfa for haylage at pre-very early bud stage, and to take 4 cuttings/year (dryland farming, avg. rainfall around 30"/year). Grassy hay would be more like 3 cuttings/year. BUT... (there's always a but), most of the
hay is grown in a crop rotation, and most of it is only left in the field for about 2 years of hay production, then it's plowed up and rotated to corn for a couple years, often followed by soybeans for a year, and then seeded down to straight alfalfa again (not typically a blend of forages). My point is, alfalfa grown this intensively is
NOT EXPECTED TO LAST... it's pushed hard for production in it's first couple years under these cutting/haying operations, and because of that, its production drops off pretty rapidly year over year after the first two... It's looked at kind of like "one and dones". Usually, in that first seeding year it's allowed to get established, and it is managed to go into winter freeze-up so it has plenty of root reserve THAT year to produce heavily in the next... but in that next season, it will be cut right up to freeze-up with less concern for root reserves, because it's intended to be rotated out anyway.
This is a very different scenario than what I'm looking for from my perennial pastures, on the very same kind of soils, in the same regional area. I want/need all of my desired plant species to be developing deep root systems, that are resilient, and that will survive, and hopefully THRIVE, even during drought, and that will be maintaining and hopefully INCREASING in production year over year. I want my grasses to be tillering... and becoming more dense. Alfalfa, though I like it in my pasture blends, doesn't typically maintain itself well over years of grazing, and will typically become crowded out by the grasses. Red Clover, an "alternative" legume component, is somewhat similar in "depth of root", although it has a more fibrous rooting system than alfalfa, and it doesn't have the same kind of "crown" which tends to be affected by grazing and hoof traffic as alfalfa is..., so it "survives" better. I put both into my blends, but the alfalfa thins out, whereas the clover can be maintained more easily.
Management strategy for ALL of the available forages out in the pasture is pretty much the same though, and the video supports this... "take half, leave half" so you don't "prune the roots", and allow for plenty of undisturbed rest between grazings. He's not suggesting in this video to "graze short", anywhere. He's pretty clear, if you take more than that, you'll be reducing the potential for forage production in the future, and the forages that are there will be less resilient when faced with challenges like drought. Plants require leaf area to facilitate the photosynthetic process. The more leaf area, the more photosynthesis the plant can accomplish, and the more "carbon" it can inject back into the system. Plants respond to grazing or cutting, by "healing" after the "injury", with increased "growth" and flow of nutrients... much in the same way that our bodies respond to injury... and it's how we build muscle by "stressing them". If the plants don't have enough leaf area remaining to get the necessary energy for this regrowth from the sun, they have to take it OUT of the roots to build back that leaf area, until it gets back to a large enough area to begin rebuilding the root system again.
Too much "stress", and we won't recover as well, and we can "go downhill". Too little stress, and we won't increase in muscle mass, and in fact, we can "atrophe".
