40 THE SOILS AND CROPS OF THE FARM. 



ly it is a light yellowish color. Clay soils usually 

 have more plant food than sandy ones; they hold 

 moisture better, and there is less loss of soluble ma- 

 nures or available plant food by leaching. They are 

 ^ard to work, and are often too cold and wet unless 

 well drained. They "heave" as the result of freezing 

 and thawiAg. 



A mixture of sand and clay makes a better soil 

 than one almost entirely composed of either. The 

 additiourof clay to sand makes it more tenacious; ena- 

 bles it the better to absorb and hold moisture and 

 gases; gives it greater capillary power; enables it to 

 withstand drouth better, and, usually, will make it 

 cooler. The addition of sand to clay makes it more 

 easily penetrable by the roots of plants; more easy to 

 work; somewhat warmer; less injured by being worked 

 when wet; less apt to "heave." 



Humus, or decayed vegetable matter in soils, makes 

 them light in weight and dark in color; greatly in- 

 creases their power to absorb moisture from the air 

 and their capillary power; makes clay soil less 

 and sandy soil more compact. It will be seen that, 

 aside from its value as a source of plant food, hu- 

 mus is important in improving the physical condi- 

 tion of the soil. Most soils containing much humus 

 are fertile, if not too wet. 



Lime in soils has a considerable importance aside 

 from its use as food for plants. It improves the tex- 

 ture by making clay soils more easily worked and 

 sandy soils more compact. It hastens the decay of 

 .vegetable matter. 



Weight. — The weight of a cubic foot of dry, loamy 

 0oil may be one hundred pounds, or even more. The 



