50 HINTS ON SOILS AND FERTILIZERS 
SOIL FERTILITY DETERMINES YIELD 
The term, “fertile soil,” has been used in this 
little booklet with reference to the amount of 
plant food in the soil. However, under prac¬ 
tical conditions, we find that sometimes a soil 
may have a good supply of the needed plant 
food elements, but nevertheless fail to yield a 
satisfactory crop. That is to say, a soil, to be 
productive, requires not only sufficient plant 
food in available form, but certain other con¬ 
ditions, such as good seed to start with, light, 
a warm temperature, protection from the 
various harmful agencies, such as insects and 
diseases, and plenty of humus, or organic mat¬ 
ter in the soil. Thus to get the maximum 
yields of our farm crops, we must understand 
that while plant food is absolutely essential, 
it is not the only factor to be considered if we 
are to get best results. 
Just what is the importance of good seed? 
Suppose we plant an acre of corn with seed 
that has poor germination. Let us say that 
the germination of this corn is 75 per cent, or 
that 75 kernels out of every 100 kernels sprout. 
The best that we can do under these circum¬ 
stances, providing we have other conditions 
ideal, is to get a 75 per cent yield. This is a 
costly affair to the farmer, as 25 per cent of 
his acre of land is wasted, and weeds will take 
possession of the wasted land, if the land is 
not closely cultivated. Of course, the farmer 
can go to the bother of replanting the missing 
fcernels, but this is also a drain upon the farm- 
