Maintain the Fertility oE Our Soils. 
i5 
in considering the question of alfalfa as a green manure. Alfalfa 
is not a plant which can be sown in late summer or early fall with 
the expectation of obtaining a growth of desirable material to plow 
under the following spring. We can only use it as a green manure 
at the end of a rotation in which the alfalfa is one of the crops, and 
involves a longer rotation than can advisably be used under Eastern 
conditions, consequently it is necessary to take other factors into the 
account. 
We have assumed that our alfalfa has yielded four tons of hay 
annually and we have removed from the soli a total of 469 pounds 
of plant food in the form of potash, phosphoric acid and nitrogen, 
or 369 pounds, considering that only one-half of the nitrogen came 
from the soil. The loss in making alfalfa hay ranges from 20 to 
66 per cent.; in other words, a four ton crop of hay gathered, repre¬ 
sents, even under the most favorable conditions, five tons cut, not 
counting the stubble. This ton lost is composed of leaves and the 
fine stems, portions richer than the average sample of hay in nitro¬ 
gen and ash constituents, and representing a total of 117 pounds of 
plant food. This, owing to our practice of irrigating after each 
cutting, especially after the first and second cuttings, is almost 
wholly incorporated into the soil, for the moisture will facilitate its 
decay and the strong stubble will prevent its being washed away 
to any considerable extent. The stubble proper is not considered 
in the preceding statement, on account of which we are justified 
in increasing this amount, 117 pounds, to 150 pounds, which alone 
is as large an amount of plant food as is required to raise a fifty 
bushel crop of wheat. It is further to be remembered that, as we 
have assumed one-half of the nitrogen added came from the air 
and the rest of the substances from portions of the soil beyond the 
reach of the wheat plant, the amount of plant food added is prac¬ 
tically a clear gain. 
So far two important points have accrued to our soil by simply 
being put down to alfalfa, a practical resting of the surface soil, 
which would be still further benefited, as I firmly believe, if we 
could give our alfalfa a cultivating, and, second, by an addition of 
plant food. These are not the only points which we will gain if 
at the end of our rotation we turn under a good growth of succu¬ 
lent alfalfa, rich in nitrogen and potash. Our soils need organic 
matter, but coarse manure or such as has been firmly matted do not 
readily pass into decay under our conditions, but the green alfalfa 
ferments easily, exercising a very beneficent influence upon the 
soil, not only adding its own available plant food, but possibly act¬ 
ing quite vigorously upon the soil itself, greatly improving the 
mechanical as well as the chemical conditions. Some of our farmers 
have already discovered that these things are facts and do not 
hesitate to turn under a fine growth of alfalfa, though some still 
look upon it as a doubtful practice. 
