268 
Journal of Agricultural Research 
Vol. IX, No. 8 
increase in solubility is due in part to the action of the inorganic salts 
contained in the organic substances or their extracts and in part to the 
solvent action of the soluble organic compounds formed during organic 
decomposition. The fact that a deficiency in soluble iron is known to 
induce certain types of chlorosis suggests that the beneficial effects 
following the addition of organic matter to Citrus soils may have been 
in part due to its solvent action on iron and other soil compounds. 
Such an effect, if it exists, has not yet been differentiated from beneficial 
effects resulting directly from the organic material added. 
