254 
ELEMENTARY AGRICULTURE 
lizers. Natural and green manures are probably the 
cheapest and the most practical for the average farmer. 
Experiments show that in some sections of the South 
good results and considerable profit has been obtained by 
applying from 300 to 600 pounds of properly mixed com¬ 
mercial fertilizer to the acre. Where commercial fer- 
Fig. 184.—Unloading seed at the oil mill. Most farmers sell the seed 
removed from the cotton at the gin. It is scooped into a trough at the oil 
mill and carried to the storeroom by a conveyor. 
tilizers are used, one application is drilled in at planting 
time and another about the time the bolls are being 
formed on the plant. 
Insect Pests of Cotton.— The Mexican boll-weevil 
is the most serious enemy of the cotton crop of the 
United States. This insect probably originated in Mexico 
or Central America and entered the United States at 
Brownsville, Texas. Owing to its rapid spread and de¬ 
structive nature, it attracted government officials in 1894, 
