30 AMERICAN AGRICULTURE. 



have become impoverished. Of the same character are most 

 of the secondary bottoms on the Connecticut, the Scioto, the 

 Miami, and other rivers. The first, ' although under cultiva- 

 tion for more than two centuries, in consequence of its divis- 

 ion among intelligent farmers, has fully maintained its pro- 

 ductiveness ; and the latter, if properly managed, are capable 

 of perpetual fertility. Although but a little more than half a 

 century has elapsed since these last have been subject to the 

 white man, they have already, in too many instances, been 

 severely cropped. The writer has seen fields, which he was 

 assured have born forty-seven large successive crops of corn, 

 and exclusively from their own resources. A more careful 

 tillage is however becoming general. 



The lower alluvial bottoms that are frequently overflowed, 

 and thus receive large coatings of manures which are fully 

 equivalent to the products taken off, are the only soils which 

 will permanently sustain heavy crops without the aid of man. 

 Such are the banks of the Nile and the Ganges, and many of 

 our own rivers, which by the overflowing of their waters 

 alone, have continued to yield large annual burthens, the two 

 former, for more than 3000 years ; but they are thus suppor- 

 ted at the expense of a natural drainage of thousands of acres, 

 which by this means, are proportionally impoverished. Ma- 

 nures then in some form, must be considered as absolutely 

 essential to sustaining soils subjected to tillage. 



In their broadest sense, manures embrace every material, 

 which if added to the soil, tends to its fertilization. They 

 are appropriately divided into organic and inorganic ; the first 

 embracing animal and vegetable substances, which have an 

 appreciable quantity of nitrogen ; the last comprehending only 

 such as are purely mineral or earthy, and which in general 

 contain no nitrogen. These characteristics are sometimes 

 partially blended, but they are sufficiently distinct for clas- 

 sification. 



Much pertinacity has been exhibited by some highly intel- 

 ligent minds, who should have entertained more liberal 

 views, as to the peculiar kinds of manures necessary to 

 support a satisfactory productiveness. We have seen that 

 Tull maintained, that the deepening and thorough pulverization 

 of the soil was alone sufficient to secure perpetual fertility. 

 But this crude notion, it is evident to the most superficial 

 modern reader, is wholly untenable. Some agriculturists of 

 the present day however, while they scout at the theory of 

 Tull, (who was really a shrewd man for his day,) will yet 



