20 BULLETIN 1410, U. S. DEPARTMENT OF AGRICULTURE 



tained. since they did not mature, but the vines reached a height of 

 1 foot. The onions also grew to a height of 1 foot but produced only 

 scallions, so that the yield was not recorded. The data for the other 

 crops are shown in Table 2. It will be seen that the 1922 yield of 

 tobacco was very poor, as compared with the yield of corn (fig. 14). 

 Double fertilization, that is, 7,000 pounds of 6-5-6 fertilizer per 

 acre gave a considerable increase in yield over a single application, 

 and liming was apparently injurious to growth. 



In 1923 the plats were divided in such a manner that tobacco fol- 

 lowed each of the other crops used in the rotation on one half of each 

 plat, the other half being grown to the same crop as in 1922. It 

 was found necessary to reseed the clover on plat 10-A, apparently 

 as a consequence of damage by rodents the preceding season. 



Fertilizers were again applied to all plats at the rate of 4,000 

 pounds to the acre of a 6-5-6 mixture, except plats 9 and 20, which 

 received fertilizer at the rate of 8,000 pounds per acre. Plats 11 and 

 22 were again treated with lime at the rate of 2,000 pounds per acre. 



Fig. 14. — Part of experimental plats at Whately, Mass., in 1922. Onions are shown 

 to the extreme left, the failure of the tobacco crop on plat 8 is shown in the cen- 

 ter, whereas an excellent corn crop may be seen at the exU'eme right 



A good stand of all crops was secured, although rodents damaged 

 the beans to such an extent that data on yield could not be obtained. 

 The effect of the preceding year's cropping on the growth of tobacco 

 was very striking during the entire growing season and contrary to 

 expectations or the assumption of a parasitic hypothesis for brown 

 root rot, although not out of line with certain observations made in 

 former years. The growth of tobacco after timothy and corn (figs. 

 15 and 16) was extremely poor, the crop being practically worthless. 

 On the other hand, the growth following tobacco and the fallowing 

 (figs. 17 and 18) of the land was very good in comparison, the 

 growth following the other crops grading between these extremes. 

 The final yields of the rotation crops in 1923 are shown in com- 

 parison with the 1922 results in Table 2. It may be noted that the 

 average yield from the single fertilization exceeds that of the double 

 fertilization and that the lime plat is intermediate in this respect in 



