ALFALFA 
9 
PAGE 
a judgment of the value of the seed. Six-year-old alfalfa 
seed had lost but little or none of its germinating power. 
Screenings give good results even when two or three years 
old. Failures to obtain a stand are due to causes other than 
the lack of germinating power of the seed. 
Roots and Stubble of Alfalfa .44-64 
The popular description of the roots exaggerated and errone¬ 
ous. Very large roots exceptional and not normal. The 
root system is very simple, Plates II to X. Fibrous roots 
are almost wanting. Spongioles found at the depth attained 
by the tap roots. Spongioles described. 
Depth Attained by the Roots. 
The depth attained by alfalfa roots varies with fehe soil; it 
may also be determined by the height of the water plane. 
Alfalfa roots are more tolerant of water than popularly sup¬ 
posed. Illustrated in Plate XIII. 
Locality in Weld County chosen for digging out samples of 
alfalfa roots, p. 48. Section of soil given, p. 48. Plants were 
five or six years old and vigorous. Roots had penetrated the 
hard layer and did not divide. Depth reached was eleven feet 
nine inches, ending in a soft sandy clay. At the next place 
chosen the soil was nearly uniform to depth attained by roots. 
This soil was a clay and was formerly used for making brick. 
Age of these plants five or six years; length of roots twelve 
feet three inches. Effect of raising the water plane, p. 49. 
Effect of Age on Size of Roots . 50 
Observations show great variation; some nine months old 
roots are larger than others six years old. 
Death Rate of Roots .50 
In five years from seeding two-thirds of the plants had died. 
. The yield of hay not affected. Dying out of the plants or thin¬ 
ning of the stand not objectionable provided it is uniform. 
The plants die in two ways, p. 51. The second mode of dying 
illustrated by plates XV, XVI and XVII. Alfalfa roots when 
cut off below the crown do not bud and reestablish the plant, 
and their power of throwing out adventitious roots is small. 
Alfalfa Roots Cut by Gophers .• . . . . 52 
Alfalfa plants endure this root pruning to a remarkable 
extent. 
Nodules on Alfalfa Roots . 5 2 '53 
These occur in three forms; as warty excrescences on the 
roots, in large colonies, and as single nodules. The first 
