314 MISCELLANEOUS FARM SUBJECTS 



A high degree of lasting fertility is usually associated with 

 .black soils, and they are usually considered more productive than 

 yellow, red, or brown soils, but many notable exceptions to this rule 

 are known. The trouble often experienced in obtaining satisfactory 

 crops on newly reclaimed swamp land and fresh muck suggests 

 itself as an example ; also the high productive capacity of the brown 

 or red soils of the Hagerstown series of central Pennsylvania and 

 the Indian red soils of the Penn series in New Jersey. The density 

 of black, as also the shade of color of the mineral matter of the soil, 

 will often indicate to a trained observer differences in soils which 

 mark decided differences in crop adaptation. 



Every 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 re- 

 mains 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 Kumus, and is the same kind of ma- 

 terial as that 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 maintenance 

 of humus a permanently productive system of husbandry cannot be 

 maintained. 



This vegetable material is derived from various parts of plants, 

 as roots, stems and leaves, and has been incorporated in the soil by 

 various agencies. The roots of some grasses and some plants pene- 

 trate the soil to a depth of from ten inches to twenty inches, and de- 

 caying become an agency in the formation of the soil. Good, pro- 

 ductive soils should contain from five per cent to ten per cent of or- 

 ganic matter. (Bu. of Soils, B. 55; 111. Col. B. 82; Cornell R. C. 

 Soils Series 1.) 



Absorption. A very important property of solids in contact 

 with liquids which tends to control the concentrations of soil solu- 

 tions and to prevent undue waste of material is the power the soil 

 grains have of absorbing and holding on to dissolved salts. This 

 absorptive power varies greatly with different soils and with different 

 minerals, and varies for different substances or parts of substances. 

 It is stronger for potash than it is for chlorine, and a weak solution 

 of potassium chloride passed slowly through a soil comes through 

 acid with hydrochloric acid, the soil having retained more of the 



