TILLAGE 



153 



plants because they prevent the stirring of the soil. A layer 

 of dry, porous earth is fully as effective in breaking up the 

 capillary chain. One of the main objects in cultivating plants 

 is to maintain a mulch of this kind, which is commonly called 

 a dust mulch or summer mulch. The dust mulch is also a 

 great aid to the suppression of weeds, since it contains so 

 little moisture that their seeds cannot germinate. In dry 



Photograph hy S. L. Alle 



FIG. 110. Cultivating with a wheel hoe 



. & Co., Philadelphia 



This implement has several attachments and may also be used as a rake, scarifier, 



or light plow 



farming the dust mulch is used to retain the moisture, and so 

 effective is it for this purpose that we are often advised to 

 " water the garden with a hoe " ; that is, to keep the water 

 already in the soil from escaping by constant cultivation of the 

 surface. The soil should be loosened after every rain. When 

 plants in large plots are cultivated, the cultivator, drawn by 



