ALFALFA ROOT STUDIES. 
VARIETIES STUDIED. 
9 
Field studies of the root s} T stems of the more common commercial 
varieties or strains of alfalfa and of forms of the yellow-flowered 
species (J/edlcago falcata) have been conducted at the Redfield field 
station at various times between 1914 and 1920. The varieties and 
strains 1 taken into consideration include the Peruvian, Poona, 2 
southern-grown common, northern-grown common, Turkestan, 
Grimm, and yellow flowered, and form the basis of the principal part 
of this study. 
The Turkestan, Grimm, and yellow-flowered alfalfas passed 
through the four-season period from 1916 to 1919. inclusive, with 
Fig. 6. — Distortions and the production of branch roots in Grimm alfalfa plants 117 
days old. These plants were confined in small flowerpots during the first 39 days. 
little thinning of stand. The southern-grown common had approxi- 
mately 22.5 per cent mortality during the period, while the Peruvian 
and Poona were almost completely winterkilled the first winter. The 
root systems of 12 consecutive plants of each variety and strain 
were taken in October, 1916, and photographed. In May, 1917, 
after growing one season, 25, 75, or 100 plants of each variety and 
strain were removed consecutively for the purpose of making obser- 
vations, measurements, and estimates of the more important root 
characteristics. Tn August and October, 1919, after growing four 
seasons, additional data were obtained by taking sets of the same 
1 For definitions and a classification of varieties and strains of alfalfa, see Farmers' 
Bulletin 757. 
2 An introduction from Poona, India. 
103923°— 22 2 
