HINTS ON SOILS AND FERTILIZERS 47 
up to the standard in lime. We term such a 
soil deficient in lime, an acid, or a sour soil. 
There is only one practical way by which this 
sour, or acid, soil can be sweetened, and that 
is by applying lime in some form. But this 
liming aids in other ways, incidentally, besides 
neutralizing the acidity of the soil. It adds 
plant food in the form of lime, which is used 
quite heavily by certain plants. Strange to say, 
other plant foods existing in the soil are made 
more available by the addition of lime. Lime 
also improves the structure of the soil, thus 
causing the soil to be more easily worked. 
It is not an uncommon experience for a 
farmer to try to get a start in raising alfalfa, 
which is without doubt one of the best forage 
crops that we have. He may choose his best 
piece of ground, and may take ever so many 
other precautions, but if the land is acid, he 
will have poor success, because, as stated be¬ 
fore, the bacteria in the soil, so essential to this 
crop, cannot exist in an acid soil. The only 
way in which he can succeed in raising this 
crop, providing he has a well drained piece of 
land, and has the bacteria introduced into the 
soil, if not already present, is to apply lime on 
this land. If this is done, the chances are very 
much in his favor in securing a good stand of 
alfalfa. 
The next problem that confronts us is the 
manner of determining the acidity of our soils. 
How can we tell if our land is acid or not? 
There are various methods of reaching a con¬ 
clusion in this matter. The old method con¬ 
sisted of using a small strip of blue litmus pa- 
