AMERICAN AGRICULTURE. 



CHAPTER I. 



SOILS. 



SOILS are those portions of the earth's surface, which 

 contain a mixture of mineral and vegetable or animal sub- 

 stances, in such proportions as adapt them to the support of 

 vegetation. Rocks are the original basis of all soils, which 

 by the convulsions of nature, or the less violent but long 

 continued and equally efficient action of air, moisture and 

 frost, have been broken into fragments more or less minute. 

 There are various gradations of these changes. 



THE TEXTURE OF SOILS. Some rocks exist in large 

 boulders or rounded stones, which thickly overspread the 

 surface and mingle themselves with the earth beneath, giving 

 to it the character of a rocky soil. The smaller sizes, but an 

 equal prevalence of the same materials, distinguish the sur- 

 face where they abound, as a stony soil. A third and more 

 minute division is called a gravelly soil ; a fourth is a sandy 

 soil ; a fifth constitutes a loam ; and a sixth, in which the parti- 

 cles of earth are reduced to their greatest fineness, is known 

 under the name of a clay soil. 



The two first mentioned, however, are not properly, dis- 

 tinct soils, as the only support of any profitable vegetation, 

 is to be found in the finer earth in which the rocks and 

 stones are embedded. In frequent instances, they materially 

 benefit the crops, by the influence produced from their shade, 

 moisture, and protection from winds ; and by the gradual 

 decomposition of such as contain lime, potash and other fer- 

 tilizing materials, they enrich the soil and contribute to the 

 support of vegetation. Their decomposition is hastened by 

 the apparently worthless vegetable life which they yield to 

 the living mosses that, cling to their sides, and every where 



