PRODUCTION OF' AMERICAN EGYPTIAN COTTON. 21 
inspected fields can be sold for planting at a price very little above 
current. oil-mill prices, thus removing the temptation to plant unse- 
lected seed because it is cheaper. 
The fact that this plan for handling the supply of planting seed 
of the Yuma variety was in successful operation when the time came 
to introduce the Pima variety in the same locahty made it possible 
to solve what would otherwise have been the very difficult problem 
of substituting one variety for another and yet keeping the new stock 
from being mixed with the old. Through the hearty and efficient 
cooperation of this growers’ association it has been possible to supply, 
in 1918, pure seed of the Pima variety for planting approximately 
70,000 acres, all of which was derived om the 250 acres planted 
near Tempe in 1916. 
If the growers’ associations continue to follow year after year the 
plan thus outlined, it is expected that deterioration, if it occurs, wiil 
be so gradual that there will be time for the substitution of another 
pure strain selected and multiplied at the plant-breeding station. 
It is to be hoped that the associated growers in other communities 
which have undertaken the production of Egyptian cotton will deal 
with the problem of pure-seed maintenance in an equally effective 
manner. 
AGRICULTURAL RELATIONSHIPS OF THE CROP. 
The outstanding agricultural feature of cotton production in the 
Southwest.is the value of the crop in the farm rotation. Alfalfa oc- 
cupies a large part of the irrigated land in that region and is the 
basis of its agriculture; but the alfalfa fields after a few: years 
become so badly infested with Bermuda grass and other weeds that 
their value is greatly impaired. It has been found that these old 
alfalfa fields, when thoroughly broken up and worked into good 
_ tilth, yield large crops of cotton. At the same time the intertillage 
of the cotton crop while the plants are young and the complete shad- 
ing of the ground later in the summer effectually rid the land of 
weeds. One or two well-tilled crops of cotton following alfalfa will 
leave the land-clean and in excellent condition for reseeding with 
alfalfa or for growing other crops. Because of its renovating value 
in the farm rotation, cotton is a valuable crop for irrigated land, 
quite aside from the cash returns it brings. 
Less water is needed for the production of cotton than for the 
production. of alfalfa, particularly early in the season. In fact, 
the total seasonal quantity of water needed for irrigating cotton is 
probably not much more than half that needed for the irrigation of 
alfalfa. The significance of this point lies in the fact that there is 
more irrigable land in Arizona and southern California than can be 
supplied with irrigation water. Hence, the growing of a crop which 
