266 DRY FARMING 



soil particles or their ability to hold together and (2) to 

 reduce the exposure of the surface soil by some form of 

 protection. 



220. The Means Employed to Prevent Excessive Damage 

 from soil blowing therefore fall into two groups, (1) 

 those that increase the resisting' power of the soil, and 

 (2) those that protect the soil surface from the wind. 

 Among the methods used to increase the power of the 

 soil to resist the wind are, (a) increasing the moisture 

 content, (b) increasing the organic matter content, and 

 (c) modifying the structure of the soil. The protection 

 of the soil surface from the wind may be accomplished 

 by: (a) growing a protecting crop, (b) letting the stub- 

 ble of one crop remain until shortly before the time of 

 seeding the next crop, or, as with corn stubble, through 

 the whole of the next crop season, (c) applying manure 

 or straw to the field, and (d) providing artificial pro- 

 tection such as the growing of windbreaks. We shall 

 take time for a detailed discussion of only the more im- 

 portant of these practices. 



221. Increasing the Moisture Content. — ^When a soil is 

 moist its particles are not as likely to become separated 

 and blow away as when the soil is dry. This fact is of 

 value chiefly to the farmer on irrigated land where water 

 may be applied at will. Under dry land conditions it 

 becomes of value only in so far as one may by keeping the 

 surface soil firm, also keep it moist to within a very short 

 distance of the Surface. The chief value of packing, in 

 the control of soil drifting, is to be found in the fact 

 that it aids in bringing moisture from below to the sur- 

 face soil, thus increasing the resistance of the particles to 

 the wind. On the other hand if there is not a fair sup- 

 ply of moisture in the lower soil, the breaking up and 



