346 MAN'S USE AND CONSERVATION OF SOILS 



scant. But most cultivated crops cannot live in a soil that 

 holds too much free water. Land must, therefore, be prop- 

 erly drained. If, on the other hand, drainage is too free, 

 it may wash the plant food out of the soil. Much more 

 moisture is lost by evaporation than by under-drainage or 

 seepage. In dry climates or during droughts, therefore, 

 mulches and frequent stirring of the top-soil must be 

 resorted to in order to conserve moisture. 



Great areas in dry climates are frequently reclaimed by 

 irrigation, while swampy lands are rendered useful by drain- 

 age. In the conservation of soils, nothing is more important 

 than wise forestry. Forests retard evaporation of soil water, 

 increase the underground supplies of water, and tend to 

 prevent great extremes of high and low water in our rivers. 

 The ruthless destruction of our forests also threatens our 

 future lumber supply. Our own government has been taking 

 steps in recent years to care for our forests scientifically. 

 It deserves the cooperation in this of every good citizen. 



QUESTIONS 



Is the soil in your neighborhood local or transported? Does 

 its character vary much in different places ? Does its fertility vary ? 

 Are the soil particles large or small? 



What would you suggest as the cause of any soil variations found 

 in your neighborhood? 



What conditions are necessary to produce a fertile soil? 



What are the best farmers doing to increase the fertility of their 

 soils? 



How can the right amount of soil water usually be maintained ? 



What steps should be taken to guard our forests ? 



