154 THE PRINCIPLES OF AGRICULTURE 



and compact the surface soil over the seed by 

 means of concave wheels about eight inches 

 wide, while the spaces between the rows are not 

 compacted. The maize may be cultivated and 

 harrowed before the plants appear, since the 

 rows may be easily followed by the marks left by 

 the concave roller wheels. The frequent inter- 

 tillage which will be required to destroy weeds, 

 to preserve the earth -mulch, and to set free 

 plant -food, will compact the subsurface soil 

 quite as much as is desirable. 



4c. Potatoes 



262. The potato should be planted deep and 

 left with uncompacted surface soil. The seed 

 potato contains about 75 per cent of moisture, 

 and has a large quantity of stored food for 

 nourishing the buds and sending up strong 

 shoots. It thrives best in a cool, moist soil ; 

 and this condition is secured if it is planted 

 about four inches deep. 



263. It should also be remembered that pota- 

 toes are enlarged underground branches, and 

 that the new tubers preferably grow above the 

 seed -tuber. If the seed -tuber be planted shal- 

 low, the branch or stem above the seed is so 

 short that there is little room for underground 

 stems. 



264. Usually potatoes should not be hiiied at 



