CHOICE OF FOE AGE CROPS 49 



alfalfa and red clover both do well in some places, the 

 latter is much better fitted for use in short rotations. 



40. Yields per acre. The yielding capacities of various 

 hay grasses and other closely comparable forage crops 

 have been tested at various experiment stations. In 

 comparatively few places, however, have such experi- 

 ments been adequate to reach clear conclusions. Some 

 of the experiment station results are shown in the accom- 

 panying table. Usually yield per acre is the most im- 

 portant single characteristic upon which the popularity 

 of a good forage crop depends. In some areas, and under 

 certain conditions, a particular forage crop will so far out- 

 yield all others that there is practically no choice. Thus 

 alfalfa is by far the heaviest yielding hay crop for the 

 irrigated lands of the West, and sorghum usually gives far 

 larger returns than any other comparable crop on much 

 of the dry land area. 



European yields that are commonly quoted are often 

 based on very small plots, necessitating multiplication by 

 a large factor to secure the acre yield. Thus the English 

 yields reported by Sinclair were usually based on weighing 

 the grass and hay from an area two feet square; and 

 those of Vianne in France on areas little if any larger. 



Some yields reported by American experiment sta- 

 tions are also based on very small plots. While these 

 as a rule give results that can hardly be secured on larger 

 plantings, yet they do give comparable values. In the 

 accompanying table, the hay grasses are arranged in the 

 approximate order of their importance. It will be noticed 

 that this order is in many cases not consistent with their 

 yielding capacities. It is questionable, however, if the 

 results at any one experiment station are sufficiently ex- 

 haustive to admit of a definite conclusion : 



