150 



DRY FARMING 



the spring will be of great value in crowding out weeds 

 in the stubble crop. 



The perennial plants, among which the native quack, 

 sweet grass and prairie rose are the most common, are 

 serious pests in many stubble fields.. They spread not only 



Fig. 60. — ^Effect of Disking Stubble Land. 



Diagram showing on the left uncultivated stubble, and on the right 



double disked stubble. Note the absence of cracks in the subsoil of the 



cultivated land. 



by seeds but by underground creeping stems. These 

 weeds cannot be controlled by burning or disking or 

 other surface cultivation. Plowing, preferably in the 

 dry season, when the roots can be exposed to the hot 

 sun and drying wind, is the only remedy for those 

 legacies of poor breaking. Other plants of a similar 

 nature are brome grass, Canada thistle and sow thistle. 

 122. Securing a Good Seed Bed. — A good seed bed is one 

 that provides the conditions necessary for germination — 

 heat, air and moisture — in optimum amount, at the right 

 depth, at the time the seed is sown. Too often the sur- 

 face of our stubble fields is too hard to get the seed into, 

 or too dry to cause germination, or covered with disked 

 stubble through which the drill cannot satisfactorily 



