Siberian alfalfa, also known as Falcata alfalfa or Yellow Flower Alfalfa, is a subspecies of alfalfa that originated in Siberia: 
Characteristics
Siberian alfalfa is a nitrogen-fixing legume that is drought and winter-hardy. It has a fibrous root system and a deeply set crown that helps it compete for limited soil moisture. It can tolerate pH levels up to 8.5. 
Uses
Siberian alfalfa is used for dry hay, greenchop, silage, and grazing. It can be used on semiarid rangelands and irrigated pastures. 
Growth
Siberian alfalfa establishes itself well in native rangelands. It enters dormancy when water is limited and regrows when moisture returns. 
Comparison to other alfalfas
Siberian alfalfa is more drought and winter-tolerant than other tap-rooted alfalfas. It is also more salt tolerant and productive. However, it has a higher percentage of hard seed, which can slow down stand establishment.