EFFECT OF PLANT ROOTS ON NUMBER OF BACTERIA 2p 



ment, plating from the same dilutions as in the second 

 count. 

 8. Tabulate the data. 



TABLE 6. Effect of Partial Sterilization on Number of Bacteria 



Exercise 10 

 Effect of Plant Roots on Number of Bacteria 



1. Collect soil samples from the immediate vicinity of 

 the roots of various plants (alfalfa, clover, etc.), and similar 

 samples i or. 2 feet away from the plants. 



2. Prepare plate counts and moisture determinations of 

 these soils. 



3. Tabulate results as follows: 



TABLE 7. Effect of Plant Roots on Number of Bacteria 



Increase or decrease .... 



