io8 ELEMENTARY SCIENCE 



the outcome is evidently going to be very bad for the human 

 race. 



However, there is no real danger if the farmers will use 

 better methods of agriculture. Science has shown how to 

 prevent loss of the fertility of the soil, and scientists con- 

 tinue each year to make new discoveries which are of the 

 greatest importance to agriculture. They have proved 

 how certain fertilizers and certain methods of farming 

 increase the crops, and they have found and developed new 

 races of plants which will yet further increase the food 

 production of the world. But the difficulty is to get the 

 farmers to heed the facts of science. Usually they do not 

 like to take the trouble to change their methods, and gen- 

 erally they stick to the old wasteful ways even in the face 

 of positive evidence that other ways are better. So our 

 hope lies chiefly in the next generation, of which you are 

 a member. It is to be hoped that your training in science 

 will be thorough enough to make you fully appreciate all 

 that science offers of improvements, both in agriculture 

 and in other great human activities. Whether you will 

 heed what science teaches or not, that is another matter, 

 a matter for you yourself to determine. 



QUESTIONS 



1. What are bacteria? 



2. Why are bacteria useful in the soil? 



3. Can green plants use the nitrogen of the air? How is nitrogen 



made available for them? 



4. Why does clover improve the fertility of the soil ? 



5. Why do we rotate crops? 



6. What are fungi, and what good are they in the soil? 



7. What things do fertilizers do? 



