8 BULLETIN 16, U. S. DEPARTMENT OF AGRICULTURE. 
per acre should result. Figure 1 shows the effect of nitrate of soda on 
grass grown in a tobacco rotation. The grass generally should be 
allowed to stand two years, when the sod may be turned down in the 
fall or winter in preparation for tobacco the next year. This fall 
plowing is a very important point, especially in the Old Belt, as it 
practically assures that the soil will be well fitted and early enough 
fitted to give the tobacco the best chance to do well. 
OTHER CROPS OF THE ROTATION. 
It is impracticable to attempt to lay out any definite rotation plan 
adapted to the needs of all tobacco farms. For the Old Belt section, 
however, where there is less diversity in so-called money crops, a 
rotation in which tobacco is followed directly by oats or wheat and 
Fic. 1.—A field of grass showing the effect of nitrate of soda. On the right the grass 
was hardly worth cutting, while on the left, where nitrate of soda was used, a 
yield of nearly 2 tons to the acre was obtained. 
then by two years of grass, as suggested above, would undoubtedly 
be found practicable and suited to the majority of tobacco farms. 
A number of possible variations from this plan will quickly suggest 
themselves. For example, if this system of cropping, supplemented 
perhaps by liberal fertilizing or manuring, tends to make the soil 
too rich for the best results with tobacco, the difficulty could prob- 
ably be overcome by introducing corn into the rotation directly on 
the grass sod in place of the tobacco. A good crop of corn should 
result, and it would do much in the way of reducing the surplus 
fertility, for corn is an exhaustive crop, particularly on. light land. 
This would lengthen the rotation to five years and bring the tobacco 
directly after corn. There is one serious objection to this plan. 
Corn frequently harbors large numbers of wireworms, which might 
