22 THE POTATO 



in fall and left nearly ready for planting, thus facilita- 

 ting spring work. Where the frost penetrates deeply, 

 or the soil is apt to run together, the land is better left 

 rough plowed all winter and fitted in spring ; but this 

 entails some loss of time, and prevents the early plant- 

 ing of potatoes. 



Sometimes it is necessary to plow in spring, and in 

 many cases it is profitable to replow when a fall plow- 



FIG. 7 A USEFUL TYPE OF SPRING-TOOTHED HARROW 



ing has been given. Under such conditions a depth of 

 not more than six inches or eight inches is advised, 

 because plowing land is attended by loss of moisture, 

 and in most cases the amount of moisture held in the 

 soil or supplied as rainfall during the growing period 

 is insufficient to insure maximum yields ; hence, care 

 should be taken to conserve all the moisture possible 

 by plowing judiciously, making and maintaining a 

 mulch of the surface soil, thus checking evaporation, 



