26 CULTIVATIOK METHODS AND ROTATIONS FOR GREAT PLAINS. 



While these values per bushel seem to be the most reliable obtain- 

 able, they are open to several objections, among which are the 

 following : 



They are much too low for all crops to agree with present prices, 

 or those obtaining when these investigations were made. As it is 

 the relative rather than the absolute prices of these crops that are of 

 most importance, this defect is not so serious as some others. If 

 these prices were relatively correct, they could be raised horizontally 

 to suit market prices at any given time, without disturbing their 

 relations to each other, by simply multiplying them by some factor 

 which would bring them all up to the proper figure. A much more 

 serious defect is found in the fact that the average prices for the last 

 ten years do not bear the same relation to each other that the crop- 

 producing power of the soil bears to those prices when sown to these 

 crops under exactly the same conditions. To illustrate, we give below 

 the average yields obtained from each of the three grain crops in all 

 the 18 tests under continuous cropping by ordinary methods and by 

 crop rotation, with the value per acre, calculated on the basis of the 

 farm price per bushel for the last ten years : 



Table IV. — Average yields on experimental plats, in bushels, and average farm value 

 per acre, based on the average prices for ten years, 1900-1909, inclusive, in North and 

 South Dakota, Nebraska, and Kansas. 



Cropping method. 



Wheat. 



Oats. 



Barley. 



Price 

 per 

 bushel. 



Farm 

 value per 

 acre. 



Continuous cropping, ordinary methods 



Bushels. 

 17.4 



Bushels. 



Bushels. 



Cents. 

 60 

 30 

 38 

 60 

 30 

 38 



$10. 44 

 9. 06 

 8.02 

 11.88 

 10.89 

 9.23 



Do 



30.2 





Do 





21.1 



Three-year rotation 



19.8 





Do 



36.3 





Do 





24.3 









It will be seen that wheat under continuous cropping produced 

 a farm value per acre of $10.44, while oats produced only $9.06 and 

 barley $8.02. . The land upon which these yields were obtained was 

 the same for each of the three crops. The climatic conditions and 

 the preparation of the soil were the same. The cost of raising the 

 crop was essentially the same for all the crops. Therefore, the farm 

 value per acre should have been the same if the farmer were to 

 receive the same profit on each crop. Such, however, was not the 

 case, as shown by the above figures. In order to make the same 

 profit from all the crops, it would have been necessary to secure 

 34^ cents per bushel for oats, instead of 30 cents and 49J cents per 

 bushel for barley. With crop rotation the results are similar; the 

 price for oats should have been 33 cents and for barley 49 cents to 

 make the farm value per acre the same as for wheat at 60 cents per 



187 



