YIELD OF ALFALFA. 
I desire to raise no hopes in the reader’s mind 
that can not be realized and I have thus sought to be 
moderate in my estimates of what alfalfa would 
yield per acre. It is a most interesting question to 
study, the possible yield of alfalfa in various soils. 
In California, with a very long growing season, we 
are assured that as much as 12 tons of dry hay has 
been harvested per acre. This of course was done 
by irrigation in a soil peculiarly well fitted to alfalfa 
growing. It may fairly be taken as the extreme 
limit of possibilities. There are alfalfa fields that 
because of unfitness of soil, do not yield more than 
one or two tons per acre. What then, ought we to 
get? 
Moisture the Limiting Factor.—Given plant food 
in the soil and proper bacterial relations alfalfa 
ought to grow about as well in one place as in an- 
other. The limiting factor in almost all crop pro- 
duction is water. Alfalfa usually does not have 
moisture enough to make a maximum crop. Even 
on wet soils, and chiefly on undrained soils, it does 
not have water enough. That is because its roots do 
not work in undrained soils so it must forage only 
on the surface. All plants drink their food; they do 
not eat as animals do. Given water enough in a deep 
pervious soil that the roots can use, and plant food, 
alfalfa will do its best. 
(249) 
