> Can alfalfa be cultivated on other types of soil than calcareous clay soil?
> Can alfalfa replace protein concentrate ?
> How difficult is alfalfa to harvest ?
> Are new varieties less persistent than older ones?
No. This is a preconceived idea, as all varieties belong to the same specie. The specie in question is Medicago media (variegated alfalfa), a hybrid of Medicago sativa and Medicago falcata.
Furthmore, breeding led to improved DM yield, protein content and resistance to pests and diseases. Therefore, new alafalfa varieties offer a higher performance compared to older varieties.
What has changed most are the farming practises which are far more agressive nowadays: bigger, faster and far more powerful equipment is used for harvesting.
Alfalfa remains a fragile plant. Cultivation practises and fertilization requirements have not kept up with the intensive farming of alfalfa over the last thirty years.