CULTIVATION. 103 



6. To regulate the supply of moisture. 



A. proper degree of moisture is an essential condition 

 for the growth of crops. Either too much or too little 

 is injurious. 



During the hot summer months, however, when crops 

 are growing fastest, they generally suffer more from a 

 lack of moisture than from an oversupply. In the case 

 of " hoed " crops, the amount of moisture in the soil may 

 be increased by proper cultivation. 



In dry weather moisture finds its way to the surface 

 by capillary attraction, and evaporates rapidly. A 

 " mulch," or light covering of straw, or leaves, or any 

 other substance, keeps the ground moist by retarding 

 this evaporation. By stirring the surface soil and keep- 

 ing it light and porous, a similar effect is produced, the 

 loose soil serving as a mulch. 



Since the pores in this soil are too large for capillary 

 action, the moisture fails to reach the surface. 



7. To afford particular treatment to special crops. 

 There are some crops that require special treatment, 



or handling of the soil about them, to insure the most 

 successful growth. 



Some plants, for instance, are supposed to thrive better 

 when the soil is built up into " hills " about them. The 

 root crops require a soil made mellow to a great depth. 



Plowing. The plow has been regarded, through all 

 ages of the world, as the characteristic implement of the 

 farmer. The first plow over used was nothing more than 

 a stick of wood, with which the ground was stirred or 

 scratched. The history of the plow and its improve- 

 ments corresponds closely to the history of civilization 

 and improvements in the art of agriculture. It is still 

 an indispensable implement of tillage. Thoroughness of 



