HOW SOILS LOSE MINERAL MATTER 1 1 "'■ 



pounds, the acid properties of humus are destroyed. 

 If a soil contains no lime tin- -mail quantities of phos- 

 phates or potash compounds usually presenl are not 

 sufficient to combine with all the acids of humus, which 

 in consequence go on accumulating until the soil he- 

 comes decidedly acid. Now, an excess of these humus 

 acids are harmful to the roots of growing plants, re- 

 tarding their growth. Not only are they injurious to 

 growing plants, but they are harmful to the bacteria 

 that form humus. An animal compelled to live in 

 an accumulation of its own manure Buffers in health. 

 So these bacteria of decay, if compelled to live in an 

 excess of the acids which they form, suffer and cease 

 to work. Lime acta as ■ cleansing agent for the bac- 

 teria of decay, by absorbing and destroying the waste 

 products they produce in the form of acids. A notice- 

 able deficiency of lime In soils is shown by an accumu- 

 lation of acid 

 111. Life in the Soil. — Ifost persona look on the soil 

 ttply a ma8S of dead mineral matter and decaying 

 parti of plants and animals. Bui the soil is far from 



being i dead mass. It is the home of countless mil- 

 of busy worifl ria, earth worms and Insed 



of many kind-. It is a great work-hop in which 



iief workers are the little -oil bacteria. It is their 

 busiit. gank matter, manufac- 



turing therefrom valuable compounds of humus and 

 and producing acids which chi >luble 



Compounds Of phosphorus and potash into plant food; 

 in short, to keep the soil alive. The materials with 

 which the work are dead organic matter, water, 



