84 SOILS 



marked influence on its ability to hold water. Fur- 

 thermore, if the surface of the soil is softened, rains 

 sink into it better. Fall plowing will leave the soil 

 loose so that it will absorb the winter rains: if 

 the surface is hard and compact, much of the water 

 runs off. All of these operations are so funda- 

 mental to successful farming that each one is dis- 

 cussed at length in subsequent chapters. 



Influence of Forests on Water Supply. The 

 influence of forests upon the water supply should 

 not be overlooked. When forests near streams 

 are removed, the soil of the adjoining farm land is 

 made dryer, and there is increased danger of floods. 

 The large body of humus beneath forest trees holds 

 an immense amount of water, like a sponge nearly 

 twice as much as its own weight when dry. In 

 times of drought, this water is given off gradually to 

 adjoining dryer land. Moreover, the air near large 

 forests contains more moisture than the air of 

 cleared areas because the trees give off large 

 quantities of water through their leaves: hence 

 farm soils in deforested areas lose water more 

 rapidly, because the air above them is dryer. There 

 are thousands of acres of land in this country which 

 have been cleared of timber to use for farming, 

 but which are nearly valueless for that purpose 

 and should revert to forest; to say nothing of the 

 wholesale destruction of forests for timber alone. 

 Policy, as well as sentiment, should induce every 

 man to |leave as much of his farm in woodland 

 as is practicable. 



LOSS OF WATER BY SEEPAGE 



The free water of all soils is continually passing 

 downward in obedience to the law of gravitation. 



