1120 
Journal of Agricultural Research 
Vol. XXX, No. 12 
Fig. 7—Comparative effects of tobacco, potatoes, and corn as preceding crops on the yield of wheat. 
The comparative results are affected by the seasonal conditions, but in most years the yields after 
tobacco have not differed greatly from those after potatoes. After corn the yields are lower— 
frequently much lower—than after tobacco and potatoes. The yields recorded are the combined 
weights of grain and straw. 
Fig. 8.—Comparative effects of tobacco, potatoes, and corn as preceding crops on the yield of oats. 
Here, again, the lowest yields are after corn. The yields generally lie between those after potatoes 
and after corn. The yields recorded are the combined weights of grain and straw 
Fig. 9.—Comparative effects of tobacco, potatoes, and corn as preceding crops on the yield of rye. 
The rye"at first seems to thrive particularly well after potatoes, but subsequently the yield more 
nearly approaches the yields following tobacco and corn. There is less difference in yields of rye 
after the lattter two crops than in the case of wheat and oats, though the results after tobacco are 
somewhat better than those after corn. The yields are expressed as the combined weights of 
grain and straw 
