SOIL AND FERTILIZERS 295 



tery, the cultivator may proceed to turn to 

 practical use what Nature has provided even 

 though he has no intimate knowledge of the 

 purposes or the processes involved. Ex- 

 perience must be his teacher and, in this in- 

 stance, at least, it is a good instructor. 



COMPOSITION OF SOIL 



Plants, we know, must feed and bi'eathe if 

 they are to live. We know further that some 

 soils provide the plants with the necessities of 

 life in plentiful quantity, others half starve 

 •them and still others feed them not at all. It 

 is obvious that the gardener, if he is to have 

 healthful, fully developed plants, must obtain, 

 at first hand or by cultivation, soil conditions 

 that will provide his plants with all they de- 

 mand. 



Soil, in a physical sense, is a substance com- 

 posed chiefly of minute fragments of mineral 

 matter with which is mixed decayed vegetable 

 and animal matter. According to its compo- 

 sition it is one of three types — sand, clay or 

 humus. Sandy soil contains 80 to 100 per cent, 

 of sand, and, owing to the absence of vegetable 

 or animal matter in any appreciable propor- 

 tions, supplies but little nutriment to growing 



