128 SOILS: PROPERTIES AMD MANAGEMENT 



The carbohydrates, having the general formula of 

 C x (H 2 0),„ include such compounds as glucose, starch. 



cellulose, dextrose, cane sugar, and the like. The fats 

 and oils may be represented in plants by such glyceridea 

 as butyrin, stearin, olein, palmitin, and the like. The 

 proteins arc l>y far the most complicated of the three 

 principal compounds, as they may carry not only carbon, 

 hydrogen, oxygen, and nitrogen, but also mineral elements 

 such as sulfur, phosphorus, lime, iron, and other elements. 

 They are compounds of high molecular weight and are 

 mostly of unknown constitution. Simple proteins, such 

 as albumin, globulin, protamins, and others, are found 

 in plants, besides certain derived proteins such as 

 proteoses and peptones. In addition to all these, there 

 is a host of other compounds that have no small influence 

 on the composition of the soil organic matter. Among 

 these are the alkaloids, waxes, tannins, phenols and their 

 derivatives, hydrocarbons, resins, acids, aldehydes, and 

 others. 



The original plant tissue, therefore, while fairly well 

 known, as to chemical constitution, is far from simple. 

 The degradation of such material, especially in the pres- 

 ence of complex mineral products, will evidently give rise 

 at first to compounds no simpler; in fact, the chances 

 are that the resulting compounds will be much more com- 

 plicated. It is only later in the processes of decay that 

 simple products result. 



90. Decay of organic matter in soils. — From the fact 

 that weathering in general is a process of simplification, 

 and since it is evident that the plant tissue as it enters 

 the soil is so very complex, the general change that the 

 organic matter undergoes must be one of simplification. 

 This simplification, however, is very slow, and many of 



