STATE AGRICULTURAL SOCIETY. 103 



The knowledge of the physical conditions which determine the 

 fertility or barrenness of soils is an indispensable preparation to 

 the study of the value and action of manures, and it is utterly 

 impossible in practice, to derive adequate return from fertilizers, 

 unless the soil either originally possesses, or has been brought 

 into, a proper physical state. 



These reasons have induced the writer to attempt presenting 

 this subject anew, in the light of the latest and fullest investiga- 

 tions, and he is confident that it is possible thus to write one of 

 the most practically useful chapters of agricultural science. 



I. The fin fn\ ess cf the particles of a soil greatly influences its 

 fertility. On the surface of a block of granite only a few lichens 

 and mosses can exist; crush the block to a coarse powder and a 

 more abundant vegetation can be supported on it; if it is reduced 

 to a very fine dust and duly watered, even the cereal grains will 

 grow and perfect fruit on it. Thus two soils may have the same 

 chemical composition, and yet one be almost inexhaustibly fertile, 

 and the other almost hopelessly barren. There are sandy soils in 

 the Eastern states, which without manure yield only the most 

 meagre crops of rye or buckwheat; and there are sandy soils in 

 Ohio which without manure, yield on an average 80 bushels of 

 Indian corn per acre, and have yielded this for twenty to fifty 

 years in unbroken succession. According to David A. Wells, 

 (Am. Jour, of Science, July, 1852,) these two kinds of soil yield 

 very similar, practically identical results on chemical analysis, so 

 far as their inorganic ingredients are concerned. What is the 

 cause of the difference of fertility ? Our present knowledge can 

 point to no other explanation tlian is furnished by tlie different 

 fineness of the particles. The barren sandy soils consist in great 

 part of coa'rse grains, while the Ohio soil is an exceedingly fine 

 powder. 



It is true as a general rule, that all fertile soils contain a large 

 proportion of very fine or impalpable matter. How the extreme 

 division of the particles of the soil is connected with its fertility 

 it is not dilTicult to understand. Tlie food of the i)lant must 

 enter it in a state of solution, or if undissolved, the jiarticlcs 

 nnist b<' smaller than we can discover w ith the best optical aids, 

 because the jxjies of the roots of plants are not discernible by 

 any microscope. The mineral matters of the soil must be dis- 



