RELATION OF SOILS TO WATER 45 



Experiment. Fill a pan or bucket with moist 

 sand, another with moist clay, and a third with 

 moist organic matter; set them in the sun to dry 

 and notice which dries last. The organic matter 

 will be found to hold moisture much longer than 

 the other soils. The power of the other soils to 

 hold moisture through dry weather can be improved 

 by mixing organic matter with them. 



We find then that the power of soils to absorb 

 and hold moisture depends on the amount of sand, 

 clay, or humus which they contain, and the com- 

 pactness of the particles. We see also how useful 

 organic matter is in improving sandy and clayey 

 soils. 



THE EFFECT OF WORKING SOILS WHEN WET 



By this time the soils we left in the pans (see 

 page 26), sand, clay, humus and garden soil, must 

 be dry. If so, examine them.. We find that the clay 

 which was stirred when wet has dried into an al- 

 most bricklike mass, while that which was not 

 stirred is not so hard, though it has a thick, hard 

 crust. The sand is not much affected by stirring 

 when wet. The organic matter which was stirred 

 when wet has perhaps stiffened a little, but very 

 easily crumbles ; the unstirred part was not much 

 affected by the wetting and drying. 



The garden soil after drying is not as stiff as the 

 clay nor as loose as the sand and humus. This 

 is because it is very likely a mixture of all three, 



