26 



CIRCULAR 4 21, U. S. DEPARTMENT OF AGRICULTURE 



rotation was very high. In 1930. overstimulation of the oats in its 

 early stages of growth resulted in a complete failure to produce grain 

 when severe drought checked the growth of the crop before grain 

 had started to form. 



The yields of oats. corn, and sorgo in this field for 16 years are 

 given in table 10. The sorgo was harvested for fodder in 1930 and 

 1931. Green weights for those years were computed from the dry 

 weight. 



Table 10. — Acre yields of crops in a ^-year field rotation at the Ardmore station 

 for the 16 years, 1911-32 



Crop 



I 1917 



1918 1919 1920 1 1921 1922 



1923 



1924 



1925 



Corn' 



Sorgo • 



Oats 



Pounds Pounds 



5.097 15.741 



10.799 17,693 



Bushel* Bushels 

 16.7 70.2 



Pounds Pounds 

 4,441 7,567 

 10,661 | 11,841 



Bushels', Bushels 

 22.5 35.2 



| 



Pounds ■ Pounds 



4, 3'sO 3, 915 



7,695 10,451 



Bushels\ Bushels 



Pounds 

 11,689 

 17, 213 



Bushels 

 65.1 



Pou nds 

 5.622 

 8,271 



Bushels 

 15.2 



Pounds 

 4.460 

 13.003 



Bushels 

 59.6 



Crop 



1926 



1927 



1928 



1929 



1930 



1931 



1932 



Aver- 

 age 





Fr. -. ::■ 



Pounds 



Pounds 



Pounds 



Pounds 



Pounds 



Pounds 



'Pounds 



Com- 9.418 



Sorgo x 17,075 



10. 175 



8,766 

 14,115 



4,433 

 9,555 



3,902 



14,375 



2.000 

 8,060 



1.500 

 1.762 



6.445 

 12,379 



Oats. 



Bushels Bushels' Bushels Bushels Bushels Bushels Bushels 



34. So. 7 57. ; 37. 5 , 3 9. 5 . 25. 9 36. 3 



. I I I I i ' 



: I jtal rreen weight. 



J Crop destroyed by hail. 



* Xo grain produced because of drought. 



Corn and sorgo were harvested for silage. The sorgo was grown 

 on manured fallow in this rotation. However, the yield of sorgo 

 in this rotation was not materially higher than the yields in other 

 fields. The air-dry weight of sorgo mature enough for silage is 

 approximately one -third of the green weight. On this basis, the 

 average yield of air-dry stover was approximately 2 tons per acre. 



The results indicate that dependable yields of feed crops can 

 be obtained throughout a period of years. Oats failed to produce 

 gram in 2 years. In one of these. 1922. hail destroyed the crop. In 

 1930 no grain was produced because of drought following a period 

 of heavy early growth. In that year the oats were cut for hay 

 after it appeared certain that no grain would be produced, and a 

 hay yield of more than 1.5 tons per acre was obtained. In some of 

 the years when -the yields of grain were low. good farming practice 

 would have dictated cutting the crop for hay. Yields of grain are 

 so varied that a carry-over from years of good production is 

 necessary. 



Sorgo and corn never were complete failures during the 16-year 

 period! In 1922. when small-grain crops were a total loss, sorgo 

 recovered sufficiently to produce a yield of over 5 tons, green weight, 

 per acre. The value of a crop like sorgo in such years cannot 

 be overestimated. In only one year after this rotation was started 

 was the yield of sorgo for silage less than 7,500 pounds per acre. 

 Calculated as dry fodder, the average yield of sorgo was nearly 2 



