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 locality 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 from 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, will 

 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 



