4K4 ANNUAL REPORT OF THE Off. Doc. 



THE NATURAL IMPROVEMENT OF SOILS. 



By Edwau]) U. Vookukes, M. A., Director of the N^eiv Jersey Agricultural Experiment Stations. 



The farmer's primary source of income is the soil; the success of 

 his operations, therefore, depends upon its original composition and 

 character, its management and the handling of the products raised. 

 The management of a soil, however, is quite as important a factor 

 as the character of the soil itself, for it may be directed in such a 

 way as to result either in rapid impoverishment, or in great improve- 

 ment in productivity. In other words, the man is the most import- 

 ant factor in farming, as in other lines of business. 



How Soils Differ. 



In studying the nature of soils, we find that they possess two 

 distinct characteristics, which have a direct bearing upon their 

 fertility, or crop-producing power; one of these characteristics is 

 the chemical, or the power which soils possess of furnishing those 

 constituents that are necessary in the growth of plants, though it 

 is not necessary that soils, perfect from the chemical standpoint, 

 that is, that can furnish an abundance of the essential plant-food 

 constituents for all kinds of plants, shall contain the constituents 

 in the same proportion^ as they are found in plants. In fact, be- 

 cause of the origin and nature of soils, those constituents which are 

 contained in them in maximum amounts are found in plants in 

 minimum amounts, while on the other hand, those constituents which 

 are contained in plants in maximum amounts are found in minimum 

 amounts in soils, thus making the value of a soil from the chemical 

 standpoint dependent rather upon the relative amounts of the four 

 constituents, which by the continuous growth of plants are removed 

 more rapidl}' from the soil than the others, viz: Nitrogen, phosphoric 

 acid, potash and lime. These are, for this reason, called essential 

 manurial constituents, and the wide differences in soils in respect to 

 their content of the substances which furnish them are due to the 

 changes which were wrought in the surface of the earth during its 

 formation, to those which have taken place since, as well as to 

 those which are going on in a small way even at the present time. 



It is believed that the original earth crust contained all the min- 

 erals now found in it, and that at the beginning they were distrib- 



