DECOMPOSITION OF SUGARS AND THEIR DERIVATIVES 79 



TABLE 18 



Composition of the Rye Plant (Stems and Leaves) at Different 

 Stages of Growth* (from W.\ksman and Tenney) 



* Calculated on the dry basis. 



ditions. To understand why certain plant residues may be decom- 

 posed when they are introduced into a soil and become an avail- 

 able source of nutrients to higher plants, and why other plant 

 materials, or the same material under different conditions, may 

 accumulate and fail to undergo destruction, is a problem involving 

 a consideration of many factors. The chemical nature of the com- 

 plex, the other substances with which it is associated in the plant 

 structure, the nature of the soil (such as physical structure, 

 chemical composition, aeration, moisture content, reaction, and 

 temperature) with which the materials are incorporated, are all 

 important factors determining the types of organisms active in the 

 transformation and the nature of the resulting material. Under 

 some conditions there are such accumulations of organic matter as 

 peat; in other instances, grassland formations or forests develop. 

 Further, the environmental conditions determine the kind of natural 

 vegetation and consequently the nature of the organic substances 

 which become added to the soil. 



Decomposition of Sugars and their Derivatives. — After 

 organic matter reaches the soil, sugars and other water-soluble sub- 

 stances are the first to be decomposed. These substances largely 

 disappear within the first few days subsequent to their attack by 

 various bacteria and fungi. A part of these is completely oxidized 

 to carbon dioxide and water, while some are incompletely decom- 

 posed with the formation of a number of various organic acids and 

 alcohols. Some fungi decompose the sugars with the formation of 



