41 
(6) The solubility of a phosphate before it is added to a soil can not 
be used as a criterion of its solubility after addition, but it may indi- 
cate its availability. 
(7) The fixation of a soluble phosphate by the soil may be influenced 
by the basicity of the soil. 
(8) Availability as determined with solvents does not agree in full 
with that indicated by plant growth. 
ACKNOWLEDGMENT. 
Acknowledgments are due and are hereby extended to Dr. W. P. 
Kelley, formerly chemist at this station, under whose supervision 
this work was inaugurated. 
