468 THE SMALL GRAINS 



512. Hand eradication. In the preceding discussion 

 practically every effective method of weed eradication is 

 mentioned in some detail except two, eradication by hand 

 and spraying. Hand work is practicable where a weed 

 is just starting, or where eradication by other methods is 

 nearly completed but a few scattering plants remain, or 

 where the weed is in isolated patches, difficult to reach 

 with a horse implement without destroying the crop badly. 

 Prevention is better than eradication, and often a bad 

 weed may be entirely prevented by constant watching and 

 hand work. Annuals are hoed off or simply pulled. 

 Biennials and perennials must be cut off rather deeply, 

 for which purpose some form of hoe is usually employed. 

 For certain weeds with single long roots, a hand imple- 

 ment called the spud is very effective. It is a chisel-like 

 tool fastened to the end of a long handle. Dropping a 

 little dry salt on the cut root will aid in the eradi- 

 cation. 



513. Spraying to kill weeds. When weeds are ex- 

 tremely bad, or when grain-growing is still done on so 

 large a scale that the usual cultivation methods of eradi- 

 cation entail an enormous amount of work and consume 

 much time, it has been found practicable to kill weeds by 

 spraying them with solutions of chemicals. The basic 

 principle is that such solutions may be made of sufficient 

 strength to kill the weeds without killing the crop, the 

 same principle that holds good in the treatment of grain 

 for smut. Where the area to be covered is large, the 

 solution is applied by large traction sprayers. Various 

 chemicals have been used with success, such as common 

 salt, iron sulfate, copper sulfate, and sodium arsenite, 

 but iron sulfate is most commonly employed. A spray- 

 ing machine is shown in Fig. 147. 



