PHYSICAL PROPERTIES OF SOILS 53 



liable information regarding their probable agricultural 

 value ; but while the physical properties should always 

 be taken into consideration, they should not form the 

 sole basis for judging the character of a soil, because 

 two soils from the same locality frequently have the 

 same general physical composition, although entirely 

 different crop-producing power, due to differences in 

 chemical composition and amounts of available plant 

 food. It is not possible from a physical analysis alone 

 to determine the agricultural value of a soil. 



Attempts have been made to overestimate the value 

 of the physical properties of soils and to explain nearly 

 all soil phenomena on the basis of soil physics, but 

 important as are the physical properties, it cannot be 

 said they are of more importance than the chemical or 

 bacteriological. In fact, the four sciences, chemistry, 

 physics, geology, and bacteriology, are all closely con- 

 nected and each contributes its part to our knowledge 

 of soils. 



