CROP ROTATION 



15 



sidering that at each station the crops in rotation and 

 continuous cropping are grown on the same type of soil 

 having practically the same previous treatment, and taking 

 into account the length of time the experiments have been 

 in progress, the comparisons are unquestionably reliable 

 to a close degree. 



19. Rotation experiments at Rothamsted. — In the 

 Rothamsted experiments, wheat grown in a four-year 

 rotation gave during sixty years nearly double the aver- 

 age yield per acre of wheat grown continuously. In the 

 case of barley the difference is also very great, but the 

 yields of barley in rotation have fallen off more rapidly 

 than wheat, owing to the latter crop coming directly 

 after the clover and so getting the greater benefit of the 

 clover sod. 



Rothamsted Experiment Station, Rothamsted, England 

 (60 Years of Field Experiments) 



The yields in continuous culture have fallen off most 

 rapidly during the first few years of the experiment, for 

 at the outset the land devoted to continuous culture was 



