138 DEPARTMENT OF AGRICULTURE GEORGIA. [424] 



The farmer, in order to avail himself of the moisture 

 and oxygen from the atmosphere, stirs his soil as deeply as 

 possible, and pulverizes thoroughly, to admit a free circu- 

 lation of atmospheric air. The soil cooling more rapidly 

 than the air at night, robs the latter of its moisture, and 

 stores it to refresh vegetation during the heat of the suc- 

 ceeding day. , 



The importance of the thorough aeration of the Soil in 

 cultivated fields is not sufficiently appreciated by our 

 farmers. 



They are too apt to consider the object of cultivation at- 

 tained when the soil is freed from weeds and grass : yet a 

 crust formed upon the surface of a cultivated field, so as to 

 exclude the air, is more injurious to the cultivated crop 

 than a moderate growth of weeds, accompanied with per- 

 fect aeration of the soil. 



Soils differ greatly in their powers of absorbing moisture 

 from the atmosphere. 



Clay soils absorb much more than sandy, and those 

 well supplied with humus more than those deficient in this 

 important substance. 



Underdrained soils absorb more than those whose sur- 

 faces bake from the effects of evaporation. 



The absorbent power of soils is influenced by the size of 

 the pores and the character of the particles of which it is 

 composed. The rapidity of absorption depends upon the 

 per cent, of moisture in the atmosphere, while the amount 

 depends upon temperature. The more finely a soil is pul- 

 verized, the greater the surface exposed to the air, and con- 

 sequently, the greater the absorption. 



The atomic composition of the particles of soil will in- 

 fluence the absorption. If the particles are sand, they can- 

 not absorb moisture, while particles of clay, composed of 

 impalpable powder, have great absorbing power. 



It is difficult to estimate the beneficial influence upon 



