VII. TYPES OF SOIL 



Light and Heavy Soils. We frequently hear farmers speak of 

 light and of heavy soils, but we should remember that the terms 

 light and heavy as applied to soils have usually no reference what- 

 ever to weight, but refer solely to the amount of force which has to 

 be exerted in tilling the land. In fact ; most so-called light soils 

 really weigh more than the heavy soils. Peat-laden soils are 

 usually light in both senses of the word. Schuebler in his experi- 

 ments, after heating a cubic foot of various soils for half an hour 

 at temperatures ranging from 100 to 122 F., found the following 

 weights: 



Quartz Sand . . . . . 100-110 Ib. 



Clay 68-75 Ib. 



Garden Loam .... 76 Ib. 



Clayey Loam 88 Ib. 



Vegetable Mold .... 31 Ib. 



Peat 30-50 Ib. 



Warm and Cold Soils. Soils are called warm or cold according 

 to their power of holding the sun's heat. The amount of heat taken 

 up and retained varies greatly for different soils. Oemler in his 

 experiments with air-dried soils obtained the following results: 



KIND OP SOIL PERCENTAGE OP ABSORPTION 



Moor Earth 100 



Sandy Humus 95 



Loam Rich in Humus . . . .90 



Clay Rich in Humus .... 87 



Light Gray Clay 81 



Coarse Sand 84 



Pure Chalk 87 



Besides the nature of the soil constituents we find that the color 

 of soils also has a marked influence on the temperature. A dark 

 soil is always warmer than a light soil. In southern France it is 

 found that chalk soils are always late because of their color. In 

 some mountainous countries of Europe the inhabitants procure 

 black earth, which they sprinkle over the snow in the spring in 



PRAC. AGRICUL. 3 33 



