FIG. 27. Crop-producing power of 30 acre-inches (wheat) 



\ 

 I 



32OOO 



\teooo 



8OOO 



"50-tfcnt 



yc/K 



vert 



ffcne 



. 28. Crop-producing power of 30 

 acre-inches (alfalfa). 



(152) 



