156 DRY-FARMING 
makes the soil more porous, and, therefore, more ef- 
fectively worked for the prevention of evaporation. 
When this practice is continued for considerable 
periods, the topsoil becomes rich in organic matter, 
Fig. 36. Dry-farm flax in Fergus Co., Montana, 1909. Yield, 22 bushels 
per acre. 
which assists in retarding evaporation, besides increas- 
ing the fertility of the land. When straw cannot be 
fed to advantage, as is yet the case on many of the 
western dry-farms, it would be better to scatter it 
over the land than to burn it, as is oftendone. Any- 
thing that covers the ground or loosens the topsoil 
prevents in a measure the evaporation of the water 
stored in lower soil depths for the use of crops. 
