118 



SUCCESSFUL FARMING 



must result from the escape of water within the soil pores. A little loss 

 will take place in this way. Such mulches must be renewed at intervals 

 more or less frequent, depending on the rainfall and the rapidity with 

 which the surface soil may become compacted'. In the. absence of rains, 

 a well-established mulch will last for a long time. On the other hand, 

 a comparatively light rain will spoil the mulch and establish capillary 

 connection with the soil below. 



Mulches of straw, manure and other organic materials are some- 

 I 



ORCHARD WELL CULTIVATED TO PREVENT EVAPORATION.* 



times used. These are very effective, but are often expensive. Such 

 mulches are most common in orchards in case of small fruits, straw- 

 berries, and sometimes for potatoes and tomatoes. 



Where green manuring crops which are to be followed promptly 

 with money crops are used, it is well to take the precaution to plow these 

 under before they have thoroughly exhausted the moisture supply of the 

 soil. Precaution should also be taken in plowing under green manure 

 crops and barnyard manure to avoid possibility of cutting off the capil- 

 lary connection between the plowed and unplowed portion of the soil. 



Courtesy of The Macmillan Company, N. Y. From "Principles of Irrigation Practice," by Widtsoe. 



