Maintain the Fertility oe Our Soils. 
i3 
EEEECTS OE ALEALEA DUE TO DEEP DEEDING. 
I will here digress a little to discuss a fact which I have made 
rather prominent and one which may seem to some as an objection 
to the alfalfa. I have stated that the alfalfa plant is an exception¬ 
ally heavy feeder, which I have shown to be the case by showing 
that the market value of the food constituents removed from the soil 
by one ton of alfalfa hay, assuming one-half of the nitrogen to have 
been derived from this source, was $7.57 at the prices which potash, 
phosphoric acid and nitrogen commanded in 1904. Some persons 
have before now asked me how it is possible to harmonize this fact 
with the observed improvement produced by putting land down to 
alfalfa for a few vears. 
«/ 
Both facts are well established, i. e., that a piece of land which 
once produced 50 bushels of wheat per acre and had been so far ex¬ 
hausted that it would produce only 18 bushels, may be so far re¬ 
stored in its fertility by being put down to alfalfa for a few years 
as to produce 35, 40 or even more bushels per acre. 
In the meantime it is very probable that an average yield of 
four tons of alfalfa hay has been cut annually. This land was no 
longer able to produce 50 bushels of wheat per acre, which, with 
the straw, would require not more than 143 pounds of potash, phos¬ 
phoric acid and nitrogen taken together, but it would very probably 
yield four tons of alfalfa hay during the season, which would re 
quire 469 pounds of these ingredients. The alfalfa crop of four 
tons per season removes a trifle over three times as much of these 
elements of plant food as a fifty bushel crop of wheat, together with 
its straw, and that from soil which has been so far depleted of its 
supply of plant food as to no longer yield more than eighteen bushels 
of wheat. 
I would not be too sure that I can fully explain this great dif¬ 
ference. It is, however, no less certainly a fact than it is that such 
land will again produce wheat at a very greatly increased rate after 
it has been in alfalfa for a few years. 
While I may not explain the facts in the case, I will suggest 
some things which are apparent. The root systems of the two 
plants are entirely different. The wheat plant has a fibrous system 
which, under favorable conditions, may penetrate the soil to a 
depth of four feet, but the conditions obtaining in our soils are not 
favorable to their attaining this depth. It is a fibrous system, one 
admirably adapted to gathering sustenance for the plant from rich, 
mellow ground, especial at no great distance from the surface, but 
not to penetrate hard soil to more considerable depths. 
The four feet mentioned as the maximum depth to which the 
wheat roots may penetrate, is probably very much deeper than they, 
in fact, penetrate our soil, unless it be in very exceptional cases. 
The alfalfa has a simple tap root system, at the best only 
