CHAPTER VII 



LIFE IN THE SOIL 



THE casual observer is too apt to look upon the soil 

 as merely a lifeless mass of matter, from which 

 various chemicals can be dissolved to be taken 

 up as food by the roots of plants. But our microscopes 

 have shown us that a fertile soil, well supplied with humus 

 from decayed organic matter, teems with life, and may 

 well be called a living soil. On the other hand, where 

 long and careless cultivation has been pursued, and the 

 soil has been continually exposed, summer after summer, 

 to the sun (for the sun is one of the most powerful of 

 agents in the destruction of microscopic Hfe in the soil 

 whether it be of a beneficial or harmful nature), and the 

 humus has all been used up, so that the bacterial life has 

 been starved out, the soil really may be termed dead. It 

 has gotten to running together hard, and washes into 

 guUies with heavy rains, and though the chemical analy- 

 sis may show that there still exists an abundance of plant 

 food in the soil, it is locked up so that the plants cannot 

 get it, and the soil has gotton into such an acid condition, 

 that the life which filled it when new and fresh, can no 

 longer thrive. 



The microscopic life in the soil, to which the soil owes 

 much of its fertility, consists mainly of the minute forms 

 which have been given the general name of Bacteria. A 



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