Arizona Agricultural Experiment Station 567 



THINNING AND TOPPING TESTS 



Spacing of Yields in pounds 



Date of plants in of seed cotton 



topping row per acre 



August 15 6 inches 904 



Not topped 6 inches 949 



August 15 12 inches 1195 



Not topped 12 inches 1276 



August 15 18 inches 1479 



Not topped 18 inches 908 



In the date of planting tests, cotton planted March 1 and 

 March 15, 1921, was frozen and killed, and, as in previous years, 

 it seemed that the best period for planting was during the last 

 ten days of March or the first ten days of April. In the spring 

 of 1921, cotton planted March 1 and 15 was seriously injured 

 by frost, but enough plants were left to give a moderately good 

 stand, and on June 30 the cotton of these plantings is showing a 

 considerable amount of bloom and is in good condition. 



VI. CULTIVATION AND MANAGEMENT OF WINTER AND SPRING 

 GRAINS, INCLUDING WHEAT, BARLEY, OATS, AND RYE 



The major part of this work has been done on the Salt 

 River Valley Farm, although some experiments have been con- 

 ducted on the Sulphur Spring Valley Dry-Farm. Yields for 

 1921 have not yet been obtained from the latter farm ; these will 

 not be very encouraging, due to extremely dry conditions during 

 the growing season. At the Salt River Valley Farm work with 

 wheat included fertility tests, rate of planting tests, and varietal 

 tests with the following results for the harvest season of 1921 : 



FERTILITY TESTS 



Pounds of threshed 

 Treatment wheat per acre 



Manure, 5 tons per acre oika 



Acid phosphate 200 lbs. per acre 2150 



Acid phosphate 86 lbs. and 



nitrate of soda 236 lbs. per acre 2804 



No treatment -. 1974 



RATE OF PLANTING TESTS 



Pounds of threshed 

 Rate of seeding grain per acre 



120 lbs. per acre 2200 



105 lbs. per acre 1665 



90 lbs. per acre 2260 



75 lbs. per acre 2564 



60 lbs. per acre 2002 



45 lbs. per acre 1'721 



