DRY-FARMING 



away from the surface unless it is har- 

 rowed to establish a soil-mulch. The soil 

 in a field that has been rolled is more 

 moist on the top than if it had not been 

 rolled, but the soil below the compacted 

 portion is much drier than it would have 

 been had the surface been left loose. 

 That is to say, the upper five or six inches 

 of soU have been made more moist by 

 rolling, but at the expense of the soil 

 beneath. 



Part of the loss of moisture from 

 rolled soil is due to the fact that the sur- 

 face is left very smooth and level, and 

 offers less obstruction to the wind. The 

 velocity with which the wind passes over 

 rolled ground may be nearly twice as 

 great as that over rough unrolled 

 ground. This means that much more 

 moisture is sucked up from the soil by 

 the wind. The chief purpose of rolling 

 in dry-land farming is to increase the 

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