COTTON HARVESTING 363 



In picking, the principal aims are : (1) rapidity of work, (2) the 

 inclusion of only the minimum amount of trash, and (3) com- 

 pleteness of work, so as not to leave in the bur an occasional 

 lock or piece of a lock. In connection with the latter, aim it 

 should be borne in mind that it is sometimes more profitable to 

 leave unpicked a lock of stained or diseased cotton than to in- 

 clude it with the main picking, since it would tend to lower the 

 quality of the entire lot, and to perpetuate disease if the seeds are 

 used for planting. 



When locks lying on the ground where they have been stained 

 by dust or mud are included with the main picking of white cotton, 

 the selling price of the whole is lowered. It pays to harvest 

 stained cotton separately or else to leave it unpicked. Cotton 

 picked while wet, unless afterwards very thoroughly dried, makes 

 a poor staple, which sells at a reduced price, because of the fibers 

 broken in ginning damp cotton. 



Yields. The average yield per acre in the United States is 

 about 200 pounds of lint, or two-fifths of a bale per acre. How- 

 ever, more than a bale per acre is often grown in productive 

 fields. Occasional yields of more than two bales per acre are 

 obtained (Fig. 154). 



340. Mechanical cotton-pickers. The models in the 

 Patent Office at Washington show that numerous cotton- 

 pickers have been invented and that most of these have 

 never been brought into use. However, within the first 

 decade of the twentieth century several cotton-picking 

 machines have demonstrated that they can pick large quan- 

 tities of cotton, that they can harvest 80 to 90 per cent 

 or more of the cotton open at the time of operation, and 

 that they can pick without including very much more trash 

 than that included by careless hand-picking. 



Many of these mechanical pickers are only partly auto- 

 matic, and require human brains and hands to guide the 

 separate picking devices. 



