PRESENT PROBLEMS IN SOIL PHYSICS AS RE- 

 LATED TO PLANT ACTIVITIES 1 



PROFESSOR BURTON E. LIVINGSTON 

 The Johxs Hopkins University 



It is from the point of view of the physiologist and not 

 from that of the analytical physicist that I propose here 

 to consider some of the most obvious and insistent of the 

 non-chemical problems of the soil. We shall thus be 

 interested not in the physics of the soil, but in the rela- 

 tion of some of its physical properties to certain plant 

 activities. This is a somewhat unusual point of view, for 

 most soil investigators have studied the soil largely to 

 the exclusion of the plant, bringing refined chemistry 

 and physics to the statement of one member of the equa- 

 tion and stating the other member largely from the 

 standpoint of the unscientific man. This generalization 

 applies to studies upon both the physics and the chem- 

 istry of the soil, but, owing to the majesty of the great 

 chemist Liebig 2 and to the multitude of his followers, 

 soil physics has nowhere received the attention which it 

 deserves, and the relation of the physical condition of 

 the substratum to plant activities remains perhaps the 

 most fundamental and at the same time most neglected 

 of all the various environmental relations. 



Since we are certain that the water relation is of ex- 

 ceedingly great importance in the control of plant proc- 

 esses, and since so many other physical soil conditions 

 depend largely upon soil moisture, I shall consider here 

 primarily only the water relation of terrestrial plants 



1 Presented in the Symposium on Problems of the Soil, before Section G, 

 A. A. A. 8., at the Washington meeting. 



iologie," 1846. 



294 



