280 BOARD OF AGRICULTURE. [Pub. Doc. 



SOIL EXHAUSTION. 



BY GEO. E. STONE, PH.D., PROFESSOR OF BOTAKY, MASSACHUSETTS 

 AGRICULTURAL COLLEGE. 



The problem of soil exhaustion is one with which the 

 farmers of ]\Iassachusetts have been brought face to face 

 for many years. The land in this State has been deforested 

 a number of times, and has been under cultivation or utilized 

 for asrricultural purposes for many generations. Hence, 

 the original condition of the soil, with the primitive store- 

 house of available plant food, has been greatly modified. 

 The two factors that exert an influence on the soil are its 

 chemical composition and its physical properties. These 

 two factors are intimately connected, and, in general, one 

 cannot be modified without changing the other. The chem- 

 ical composition of the soil is fully as important for plant 

 growth as its physical properties. The soil, however, may 

 contain tons of plant food which are not available. On the 

 other hand, the physical conditions of the soil should be 

 adapted to the plant, in order that normal root respiration 

 may take place. Unless the physical conditions are adapted 

 to the plant requirements, the amount and kind of available 

 plant food exert very little influence upon the growth of 

 plants. Many plants, however, possess a wide range of 

 adaptability, and are not restricted to a definite soil texture. 

 In some cases it is also essential that the particles of soil be 

 of sufficient size, and their arrangement of a certain order, 

 so that air spaces of a definite size are formed, adapted 

 to the particular plant under cultivation. It is, therefore, 

 not only the size of the particles but their arrangement 

 which determine the physical properties of the soil. The 

 water-retaining capacity of the soil is dependent upon its 

 physical properties. A light, sandy soil from Cape Cod 

 possesses a water-retaining capacity of thirty-five per cent, 



