10 FERTILIZERS 



deeper applications without serious root disturbance 

 are unknown. As a result roots are encouraged 

 near the surface, and this fact is the best argument 

 advanced for the use of the most water soluble forms 

 of fertilizer obtainable, as they are more widely dis- 

 tributed by the movement of water. (77) (79). 



SOILS AND ROOTS. 



12. The permeable character of the soil influences 

 the root development, aside from the question of 

 plant food. In clay or adobe soils there is a limited 

 root development and a resultant smaller tree. 

 "Hard pans" near the surface have the same limit- 

 ing influence. In such soils, more trees can be 

 planted to the acre. 



Open, free loams or gravelly, sandy loams permit 

 a larger root development and trees should be 

 placed further apart. These are usually local ques- 

 tions, but should be considered by the intending 

 planter. The mechanical or physical nature of the 

 soil should be known to a considerable depth. (20- 

 22). 



