TYPES OF FARMING 



319 



FIG. 211. "Hungry soil." Sand. To" left, unfertilized. Yield of potatoes, thirteen 

 bushels per acre. Yield of corn, three bushels per acre. (Wisconsin Station.) 



FIG. 212. Profitable sand. Corn on clover sod, manured. (Wisconsin Station.) 



are easy to build and dairy cows will turn into profit large quanti- 

 ties of roughage that can be produced so readily on sands. Further- 

 more, the manure produced can be used to good advantage in soil 

 improvement (contrast Figures 211 and 212). An extra silo for 



