114 THE BUSINESS OF FABMING 



turity and growth of plants ; that nitrogen is the 

 "most precious, the most important and the most 

 costly," and the element soonest farmed out of 

 our soils, yet when we become nature students, 

 use our brains, closely observe the structure of 

 soils, we find that the new, rich organic soils just 

 reclaimed from the wilderness of tree and plant 

 growth are filled with decayed and decaying trees, 

 underbrush, roots and grasses; that these sub- 

 stances decaying, become the organic matter of 

 the soil upon which the soil bacteria feed, and 

 these substances decayed, or what is left of them 

 after the decaying process, become the humus of 

 the soil, thus making up and constituting two soil 

 elements so necessary to make it fertile and bear 

 its burden of crops. 



The nature student when called upon to act 

 in the capacity of "soil doctor " and to diagnose 

 sick soils soils that no longer produce paying 

 crops, like the skilled physician, quickly perceives 

 that these sick, worn, and worn-out soils, have 

 become sick because their supplies of organic 

 matter, humus and nitrogen, have been consumed. 

 He discovers that while they may possess in 

 available form the mineral elements necessary 

 for the proper working of their functions, yet 

 they lack the elements of organic matter, humus 

 and nitrogen in sufficient quantities so that they 

 will become a favorable home for soil bacteria 

 who compound plant food so that plants may not 

 only grow, and bear their burden of crops, but 

 will also release and make available these mineral 

 elements in the soil to furnish food for future 

 plant growth. 



