212 LESSONS IN AGRICULTURE 



2. If two- tons of hay per acre is an average yield, 

 how much of each fertilizer is removed yearly with the 

 crop from eight acres of ground? 



3. Which kind of hay makes the richest manure? 

 Why? 



4. How much more of nitrogen in a crop of twenty- 

 five acres of clover hay, yielding three tons per acre, 

 than in the same number of acres of mixed hay yielding 

 two tons per acre ? Where does this extra nitrogen come 

 from? 



5. How many tons of each kind of hay did you 

 raise on the farm last year? 



6. How many tons of hay did you sell last year? 

 How many pounds of each of the three important kinds 

 of "soil fertility" did you sell? How many pounds 

 altogether ? 



Free Bulletins, U. S. Dept. of Agriculture 



No. 89. Cowpeas. 



No. 194. Alfalfa Seed. 



No. 214. Beneficial Bacteria for Leguminous Crops. 



No. 215. Alfalfa Growing. 



LESSON LXIII 



CROP ROTATION 



Necessity for crop rotation. The sowing of clover 

 seed on our wheat ground and the spring planning for 

 corn, suggests the subject of crop rotation. If we are 

 to farm wisely and be prosperous, we must study and 

 practice crop rotation. The farmer tries to raise those 

 crops which will give him the largest returns in money, 



