34 PRINCIPLES OF AGRICULTURAL CHEMISTRY 



soil bacteria, those which convert inert organic matter into 

 nitrates included, and thus increase the supply of plant food. 

 The phosphate added may affect the physical character of the 

 soil. Increase in the soluble plant food in the soil decreases the 

 need of the plant for water and its transpiration becomes less. 

 Increase in temperature increases the action of soil moisture 

 upon plant food constituents, and increases the activity of the 

 soil organisms. Thus a change in one condition of plant life 

 may, and usually does, affect more than one, and the conditions 

 are not absolutely independent. 



