i8 FARM AND SCHOOL PROBLEMS. 



the drainage of these extensive areas would amount to $278,000,000. This 

 would represent an income of 6 per cent on how much capital or wealth? 



Drainage is one of the first and most important of farm 

 problems. 



When water stands on the ground or near the surface for 

 a certain length of time it interferes with the operations of the 

 farm and with the growth of crops in some of the follow- 

 ing ways: 



1. It prevents or retards tillage, planting, cultivation and harvest- 

 ing. 



2. It renders soils soggy, compact and causes acidity. 



3. It prevents the proper condition of temperature, moisture and 

 ventilation. 



4. It does not remove the more soluble salts formed by the decay 

 of rock and organic matter and gives rise to alkali lands. 



5. It causes stagnation of soil water; prevents aeration; excludes 

 oxygen. 



Wet soils remain cold because of the following reasons : 



In undrained lands which contain more than 20 per cent 

 moisture (which is about the average amount of moisture for 

 growing crops) the 'surplus water must be removed to a very 

 great extent by evaporation. 



In the evaporation of one pound of water, as much heat 

 is required as would raise the temperature of 21 square feet of 

 surface soil, one foot deep, one and one-fourth degrees. The 

 waste of sunshine in evaporation of moisture in a soil containing 

 over 20 per cent moisture is very great. 



Very few of the cultivated crops will grow where the soil 

 temperature is below 45 F. The maximum results are reached 

 at about 70, which is about the proper temperature to germinate 

 corn. 



Necessity of Soil Ventilation. 



Oxygen is as necessary in the soil for its different forms 

 of life as it is in the air that we breathe. 



Oxygen performs various uses in the soil, as, 



(a) Removing undesirable gases, caused by germination and 

 growth. 



(b) It is essential to germination. 



