— 47 — 
deep feeder and furnished a very convenient explanation 
for the observed effect of an alfalfa rotation upon an ex¬ 
hausted soil; but it is contrary to another fact which has 
also been observed, i. e., that alfalfa responds quickly to 
top dressings of fertilizers, barnyard compost and ashes be¬ 
ing the fertilizers here referred to. Other fertilizers may 
produce equally quick and marked effects, but reliable ob¬ 
servations have been made with these two. The spongioles 
were found mostly at or near the depth reached by the tap 
root. The form and size of it varied greatly. It was as a 
rule cylindrical, from one to one and a half inches long and 
terminated by a rather stiff hair-like projection. The root 
leaving it was much smaller than the spongiole for several 
inches behind it, and, consequently, was growing in a free 
space made by the extending spongiole. The amount of 
work done by the plant in this manner is very great. While 
the cylindrical form prevails, others also occur, a double 
cone shape being quite common. As already intimated, 
these were not found in large numbers near the upper part 
of the roots ; and at no other point except where the soft¬ 
ness of the ground and a greater abundance of food encour¬ 
aged their development. Such conditions were found, for 
instance, in refilled prairie-dog holes which were always 
crowded with them and in places very thickly so. 
THE DEPTH ATTAINED BY THE ROOTS. 
* 
•The depth to which the roots penetrate and at which 
they feed varies, as a matter of course, with the soil ; and in 
cases where the permanent water table lies within twelve 
feet of the surface, with this also, as the roots do not accord¬ 
ing to my observations enter the water for a greater dis¬ 
tance than from four to eight inches. The popular notion 
that the roots cannot endure the water, but cease to grow 
and decay as soon as they reach it, is not substantiated by 
observation. They do cease to extend further downward, 
but all that I have had opportunity to observe were healthy 
and vigorous. I entered the permanent water plane at two 
localities where I dug out the roots. In one instance the 
water was alkaline (Jas. Whedbee’s place, i A miles from 
Fort Collins); in the other (Rocky Ford, Otero County) the 
water, an analysis of which will be given later, was as bitter 
as a solution of Epsom salts. The roots, however, penetra¬ 
ting it were not dead. In the former case the water was 
only six feet seven inches and in the latter twelve feet from 
the surface. The roots do cease to descend, as would be ex¬ 
pected, when they reach permanent water; but they do not 
on the other hand continue their downward growth under 
