The Healthy Soil 7 



accumulation of which may render the soil sour. It 

 therefore becomes imperative to so use or to so mix 

 these fertilizers that their residues will combine and 

 thus neutralize each other. One reason perhaps why 

 greenhouse men favor the use of manure is that they 

 have experienced the bad effects of the residue of 

 improperly mixed fertilizers. 



Soil Flora 



By a soil flora is meant the bacteria or fungi, 

 whether beneficial or harmful, which thrive in that 

 soil. Science has proved definitely that a soil can 

 no longer be regarded as a conglomeration of dead, 

 inert particles of rock. The soil teems with life 

 which to a large extent determines its fertility. The 

 more numerous the beneficial bacteria and fungi it 

 contains, the more fertile it will be. On the other 

 hand if the beneficial micro-organisms are absent, or 

 perform their work imperfectly, or if the soil is 

 overridden by harmful parasitic bacteria or fungi, 

 we speak of it as a sterile or sick soil. In the green- 

 house, the soil flora is often entirely different from 

 what it is outdoors. This is due to the fact that the 

 soil is artificially made up of a mixture of various 

 ingredients with the object of making it ideal for 

 plant growth. It is imperative that the greenhouse 

 manager possess some knowledge of bacteria and 

 fungi, and that he understand the functions and the 

 requirements of the soil micro-organisms, if he wishes 



