CROP ROTATION COMPARED WITH CONTINUOUS CROPPING. 25 



grown in the rotation. The rotations giving the best yields of wheat 

 seldom give the best yields of oats, and the best rotations calculated 

 on an oat basis are not the best for barley. In order to make the 

 necessary comparisons we must be able to reduce the figures repre- 

 senting the yields in bushels per acre of all the crops in the rotation 

 to a common unit of measurement. This has been done for wheat, 

 corn, oats, and barley. 



The Bureau of Statistics reports a as follows concerning the aver- 

 age farm price per bushel for the ten years 1900-1909, inclusive: 



Average price per bushel for wheat, corn, oats, and barley, in four States, 1900-1909. 



State. 



Wheat. 



Corn. 



Oats. 



Cents. 

 31 

 29 

 29 

 33 



Barley. 



North Dakota 



Cents. 

 68 

 67 

 63 

 67 



Cents. 

 44 

 37 

 35 

 40 



Cents. 



38 

 37 

 36 

 39 



South Dakota 



Nebraska 



Kansas 



Average 



66 39 



30 



38 





These four States were selected as giving a more reliable basis than 

 could be obtained by including Montana, Wyoming, Colorado, Okla- 

 homa, Texas, and New Mexico. All of these latter-named States 

 have a portion of their territory lying within territory where local 

 conditions of supply and demand very seriously affect both the rela- 

 tive and the absolute prices. On the other hand, the four States 

 first named lie entirely within the Plains region, with sufficiently 

 free access to the large grain markets to insure them against any 

 serious influence from purely local conditions. The figures given will 

 therefore be used, after making one correction, for calculating the 

 value of the rotations. This one correction is in the case of the price 

 for wheat. The figures given are the averages for all the wheat 

 marketed in the four States specified. This includes durum as well 

 as common wheats. Durum wheats were used exclusively in our 

 experiments with spring wheat. The price of durum wheat has 

 nearly always been less than the averages for all wheats — just how 

 much lower on the average for the last ten years we have no means 

 of knowing. Neither have we any satisfactory basis for calculating 

 the percentage of durum to the entire wheat crop of these States. 

 It has therefore been decided to arbitrarily reduce the above estimate 

 to 60 cents per bushel for durum wheats. It is probable that the 

 reduction should be greater than this rather than less, but in the 

 absence of any more satisfactory basis the following prices in cents 

 per bushel have been adopted: 



Durum wheat 60 | Oats 30 



Corn 39 I Barley 38 



187 



.a Crop Reporter, December, 1909, p. 82. 



