AFTER CARE -—— FERTILIZERS 39 
plant food required are made up by minerals, 
such as nitrate of soda, acid phosphate and 
muriate of potash. 
The statement is often made that well- 
rotted manure, thoroughly worked into the 
soil, is the best fertilizer. This is quite true 
in the majority of cases, especially where an 
abundance of the material is used. 
Why is this so? 
1. Manure contains a large amount of 
vegetable material, sometimes called humus, 
which improves the physical conditions of 
the soil by: 
(a) By making a clay soil less compact, 
resulting in a more open and porous soil. 
(6)By making a sandy soil less leachy and 
porous. 
(c) By making both these soils retain 
more water, thereby somewhat preventing 
drought. 
(d) By permitting ease of root growth. 
(e) By giving the roots greater feeding 
surface. 
(f) By increasing the activities of the soil, 
thereby increasing the available plant food, 
etc. 
Oftentimes, from lack of humus, low 
