The Soil: Its Use and Abuse 



1359 



HUMUS 



E^'-ery good soil contains organic matter. The most famous soils, such 

 as those of the Genesee bottoms, the prairies of the Northwest, or the 

 valley of the Nile River, are well stocked with the decayed remains of 

 plants and animals, which generally impart a dark or black color. The 

 presence of much organic matter greatly increases the productivity of 

 any soil. The experienced farmer usually identifies a dark colored soil 

 as a fertile one for this reason. 



Organic matter in this partially decomposed and darkened condition 

 is commonly known as humus, and is the same kind of material as that 



Fig. 8. — Mtick soil, which is the decayed remains of swamp plants, is especially well 

 adapted to certain truck crops when drained and properly fertilized 



which leaches from swamp and manure heaps in the form of a brown 

 liquid. This partially decayed plant and animal material is the most 

 valuable single constituent of the soil and the one which every good farmer 

 strives to save and augment. It helps to keep the soil loose and friable, 

 improves its drainage, makes it warmer than it would be otherwise, helps 

 to hold water in a form available for crops, and renders more available 

 the store of food which every soil contains. The maintenance of humus 

 is accomplished by leaving as much of the crop as possible (stubble and 

 roots) on the soil, by turning under green crops occasionally, and by the 

 addition of manures from the stable or the factory. Without the main- 

 tenance of humus a permanently productive system of husbandry cannot 

 be maintained. 



