SOILS 21 



place at the surface, and prevent the crop being de- 

 stroyed by lack of moisture. Injurious results from 

 subsoiling in spring have been noted, probably due to 

 the working of the subsoil when it was too wet. It 

 does not follow that because the surface soil to the depth 

 of eight inches is dry enough to plow the subsoil will 

 be, and in many cases the subsoil has been puddled 

 by spring working, and the supply of moisture from 

 below more or less completely cut ofif, with disastrous 

 results to the crop. 



Preparation of the Soil. — The ideal crop to pre- 

 cede potatoes is timber, but as no rotation comprising 

 this crop is in use, the preparation given after timber 

 demands little attention. Potatoes are more commonly 

 grown after potatoes, com, or after clover or sod. In 

 such cases preference is usually given to fall plowing, 

 accomplished during Odlober or November until freez- 

 ing prevents further work. Deep plowing should be 

 done in fall, because opportunity is then given for the 

 storage of water in the soil during the winter and 

 when the thaw occurs in spring. If manure is to be 

 applied it is spread before plowing, but, if rotted, it may 

 be applied later and disked in. The depth of plowing 

 varies with the soil, probably six inches or eight inches 

 being most common, although, if the soil will permit, 

 eight inches to twelve inches will be better. When 

 soils are deficient in humus, it is generally inadvisable 

 to plow deeply. The humus content of such soils 

 should be increased and the depth of plowing increased 

 correspondingly, thus bringing the land into a higher 

 state of produdlion. In some distridls where the snow 

 covers the ground all winter the land is harrowed well 



