270 



CEOP ROTATION 



Proper Rotation With Use of Fertilize? s Increabes Productive Power of a 



Depleted Soil 



(Yield of corn gro^n m a o-year lotation) 







Average 

 yield for 



Average 

 yield for 



Decrease and 







fiist 



fourth 



increase m yield 



Cropping system 



Soil treatment 



5-year 



5-year 



m 20 years 







period 



peiiod 



(per cent) 







1894-1898 



1909-1913 









Busheh 



Bvshels 





Corn continuously 



No treatment 



26.26 



844 



67.8 decrease 



Corn in 5-year ro- 











tation"*" 



No treatment 



3189 



20.31 



36.3 decrease 



Corn continuously 



Commercial fertilizers 

 (mixed) (250 lbs 











per ciop)t 



38 86 



26 83 



30.9 decrease 



Corn continuously 



Manure (5 tons per 











acre per year) 



43.13 



30 22 



30 decrease 



Com in 5-year ro- 



Commercial feitilizers 









tation 



(imxed) (985 lbs 

 for each 5-year 











period) t 



35.78 



4410 



23 2 mcrease 



Com in 5-year lo- 



Manure on com and 









tation 



wheat (8 tons per 

 acre, or 16 tons per 











rotation 



40 73 



55 83 



37 mcrease 



* Rotation consisting of com, oats, winter wheat, clover and timothy grown m the 

 order named 



t Siity pounds of acid phosphate, 30 pounds of muiiate of potash and IGO pounds of 

 mtrate of soda apphed annually 



t One hundred sixty pounds of acid phosphate and 80 pounds each of muriate of potash 

 and mtrate of soda apphed to corn and oats ciop, and IbO pounds acid phosphate, 100 

 pounds muriate of potash, 25 pounds dried blood and 60 pounds mtrate of soda apphed 

 to each wheat crop 



It is interesting to note that the yield of corn decreased thirty 

 per cent in twenty years when grown continuously; even though 

 manure was applied at the rate of twenty-five tons for each jfive- 

 year period. In the rotation, on the other hand, the yield increased 

 thirty-seven per cent during the same period, manure being applied 

 at the rate of only sixteen tons for each five-year period. Similar 

 results were secured in the use of commercial fertilizers. 



The above results also show that rotation without fertilization 

 does not permit so rapid a reduction in the yield of corn as con- 

 tinuous cropping. Moreover, rotation gives greater returns from 

 manure and commercial fertilizers than a one-crop system. 



In the same series of experiments it is interesting to note how 

 rotation increased the yield of winter wheat. 



