250 ALFALFA FARMING IN AMERICA. 
There is hardly any other plant that will so thor- 
oughly pump the moisture out of soils as alfalfa. 
Its roots reach down deep, its leaves transpire a 
vast amount of water every day. For that reason 
alfalfa is not usually very beneficial to a young 
orchard, as it dries out the land too much. The 
writer has seen a thick stand of Kentucky blue grass 
so dried out by the alfalfa growing with it (the grass 
an intruder) that it killed it out, root and branch. 
This of course is most unusual; as a rule the grass 
lives long enough to choke the alfalfa. 
Amount of Water Used.—Unfortunately no one has 
determined the amount of moisture used by alfalfa 
in making a pound of dry matter. Taking the red 
clover plant as a guide we may assume that it re- 
quires from 400 to 500 pounds of water for each 
pound of dry matter made. Guessing that it takes 
450 pounds of water to make one pound of dry mat- 
ter we reach the conclusion that to grow six tons of 
alfalfa hay will require about 2,500 tons of water. 
That is equivalent to about 25 inches of rainfall, if 
none of it were lost. There is beside a considerable 
loss by evaporation from the soil. To balance that 
we know that we have a store of subsoil moisture 
gathered during the winter and early spring rains. 
Now, the rainfall during the 18 weeks that alfalfa 
makes its hay crops (in the cornbelt region) is sel- 
dom more than 18 inches and is often very much less 
than that. So it is clear that lack of moisture is 
often the limiting factor in alfalfa growing. For 
that reason the writer, while he has grown six tons 
