S6 HINTS ON SOILS AND FERTILIZERS 
tides are not as close together as they were, 
thereby greatly discouraging capillary action 
and evaporation of moisture. 
As the capillary moisture is contained mostly 
on the surface of the soil particles, it can be 
seen that the smaller the particles are, the 
greater the amount of moisture which can be 
contained in one cubic foot. One can realize 
this perhaps more vividly, if he takes an apple, 
and cuts it up into four quarters. He can then 
realize that he has more surface of the apple 
exposed, when thus cut up, than he did before 
the apple was dissected. Consequently, a soil 
containing fine soil particles, such as clay, or 
even silt, has much more capillary moisture 
capacity ttyam has a sandy soil, as the sandy 
soil particles are the largest in size, and the 
spaces between them too large to cause capil¬ 
lary action. This partially explains why a sandy 
soil will not withstand a dry spell as well as a 
clayey soil. 
Another source of moisture supply in soils is 
the amount of organic matter contained in the 
soils. This has been mentioned before, but we 
will discuss it more in detail at this time. We 
have seen that the organic matter plowed under 
acts somewhat like a sponge, in that it retains 
the moisture in the plowed area to a certain 
extent. This aids the plant during the dry 
spells, as it furnishes the soil particles with 
moisture if the supply below is exhausted. It 
also aids in another way, by preventing too 
much of the water during a heavy rain from 
leaching down through the soil. Besides these 
advantages in regard to moisture, it also aids 
