SOIL FERTILITY 



county, Canada, 71 per cent of the children from 

 schools with gardens passed their high school ex- 

 aminations, while from schools without gardens 

 only 49 per cent passed. This was a gain of 22 

 per cent during the three years the Macdonald 

 school had been established there. American 

 teachers also report growth in mental alertness, 

 in the sense of responsibility for school property 

 and appearance, and less disorder and naughtiness 

 from the exuberance of animal spirits that now 

 find a safe vent in gardening. In the large garden 

 of the National Cash Register Company the men- 

 tality of the boys who entered as farmers was 

 increased 30 per cent, while their morals so im- 

 proved that city lots, safe at last from their 

 depredations, rose in value from $200 and I300, 

 to $400 and $600. 



It is fundamental for school gardeners to under- 

 stand how to create soil fertility and preserve 

 reasonable moisture. Upon these, more than 

 upon anything else, successful crops depend. 



Soil, "that part of the earth which can be culti- 

 vated and in which plants can grow", is dis- 

 integrated rock with more or less decayed and 

 decaying organic matter — vegetable or animal — 

 mixed through it. Such matter is called humus, 

 or sometimes "vegetable soil" because so largely 

 composed of decaying vegetation. When soils 

 are divided according to their texture, they 

 are known as gravel, coarse sand, medium 

 sand, fine sand, very fme sand, silt, clay and 



85 



