24 CIRCULAR 4 21, U. S. DEPARTMENT OF AGRICULTURE 



The average yield of all plots as given here is not exactly the same 

 as given in table 2, as all years are not included in the average. For 

 example, barley represents an average of the last 9 years only, be- 

 cause barley was not grown on a field scale prior to 1923. With corn 

 the year 1917 is omitted, because no field was harvested as ear corn 

 in that year. In other words, average yields of plots appear for only 

 those years in which comparable fields were harvested. 



The most striking feature of the results is the fact that crops 

 grown on a field scale produced yields nearly as high as and in some 

 cases higher than those obtained on the plots. This result was 

 hardly expected as the rotations were on land slightly above the 

 average of the whole farm in general productiveness. 



The greatest difference in favor of the plot yields was with corn. 

 Part of the difference was real, but part of it was due to the fact that 

 corn was grown largely for silage, and the most productive fields 

 were generally put in the silo. Corn harvested for grain, except for 

 one or two fields, was the portion of the crop not needed for silage. 



The average yields of sorgo on plots and on fields were nearly 

 equal although much variation between plots and fields was shown 

 in individual years. In 1917 and 1923 all fields of sorgo were har- 

 vested as silage, and no yields of air-dry fodder were obtained 



The yield of oats on plots exceeded that of oats in fields, but the 

 difference was not great. 



Barley in fields produced a higher yield than barley in plots. This 

 is accounted for by the fact that a proportionately high number of 

 barley plots was grown under poor conditions. In the fields barley 

 was generally grown after a cultivated crop or on fallowed land. 



The average yields of alfalfa from fields and plots were practically 

 equal, although there were material differences in individual years. 

 The yields. of alfalfa on plots were the yields obtained the second 

 and third years after planting. The yields from fields generally rep- 

 resent those of established fields that were kept in alfalfa for longer 

 periods of time. Yields from plots are sometimes much higher, but 

 this is balanced by the fact that failure to obtain a good stand some- 

 times reduced the yields of plots. 



Alfalfa in fields was usually stacked in the field and weighed when 

 hauled. There was always a certain amount of loss from weathering. 

 If the weights had been obtained when the alfalfa was stacked, the 

 field yields would have exceeded the plot yields, which averaged 

 nearly three-fourths of a ton per acre. 



The comparative figures as a whole indicate that farmers should 

 be able to obtain average yields at least as high as the averages of 

 all plots. 



Figures on crops harvested for silage are not given in table 8, 

 because none of the rotation plots were harvested for silage, but it 

 can be stated that there never was a total failure of corn or sorgo 

 for silage in the 20 years that the station operated. In such years 

 as 1917, 1930, and 1931 the silo utilized a crop of corn that would 

 have been worthless for husking. 



Results of fields also show the possibility of successive years of 

 low yields and the desirability of carrying over grain reserves from 

 years of good production. 



