HINTS ON SOILS AND FERTILIZERS £5 
because the roots of the plants will not grow 
if they cannot obtain air. Also, it is a common 
expression amongst soil experts, to say that 
crops will not grow when they have “wet feet.” 
This means that the roots of plants will not go 
down into the water for their plant food, be¬ 
cause they would be unable to breathe, if they 
did. The presence of air also favors the de¬ 
velopment of beneficial soil organisms and is 
an aid to certain valuable chemical changes 
which are continually taking place in the soil. 
From what has been said, it is evident that 
there are several other factors determining the 
yielding ability of a soil, besides the mere 
amount of plant food contained in it. Not that 
it is the desire of the writer to lessen the im¬ 
portance of the presence of available plant food 
in the soil. This matter is all important. But 
it is not the only factor to be borne in mind, 
if w r e are to get the most from our soil. We 
must also lock to such matters as proper tilth, 
good seed, favorable temperature, protection 
from natural enemies, and bear in mind the 
importance of replenishing the soil constantly 
with a sufficient amount of organic matter. 
When we take these precautions, we will have 
little difficulty in securing excellent results 
for our efforts. 
