THE SUNFLOWER AS A SILAGE CROP. 7 
(2) Plant early. Plant the sunflower seed in a well-stirred yet firm bed as 
early in the spring as the condition of the ground will permit. Although heavy 
freezing is injurious to the young plants, light frosts do not hurt sunflowers. 
(3) Harrow. When the young plants begin to appear, use a spike-tooth har- 
row adjusted for shallow cultivation. 
(4) Thin the plants in the rows. Make the rows as far apart as corn is 
usually planted. When the shoots are well started, thin to one or two plants 
to the hill, 30 to 36 inches apart in the row. 
(5) Cultivate thoroughly. Cultivate lightly with an ordinary corn cultivator 
as often as needed. 
SOIL RELATIONS AND EFFECT ON THE FOLLOWING CROP. 
No very definite information regarding the behavior of sunflowers 
on different soil types is available. The best yields are obtained on 
rich clay loams well supplied with humus, but the crop has been 
grown successfully on sandy soil in northern Michigan and on poor 
clay soils in West Virginia. Sunflowers will thrive on any soil which 
will produce a good crop of corn. 
It was observed on the fields of the Washington Agricultural Ex- 
periment Station (77, p. 11) in 1919 and 1920 that the outside rows of 
the sunflower plats next to the corn made a more vigorous growth 
than rows in the centers of the plats. Conversely, the corn rows next 
the sunflower plats were less vigorous than the rows in the centers 
of the plats. This seemed to indicate an ability on the part of the 
sunflowers to obtain a greater portion of the plant food and soil 
moisture than corn when grown in competition with that crop. The 
plats which produced corn and sunflowers in 1919 were seeded to 
wheat in 1920. The average yield of wheat on the corn plat's was 
33.78 bushels and on the sunflower plats 28.36 bushels per acre. These 
results at the Washington station indicate that sunflowers are more 
exhaustive of the plant food and moisture in the soil than corn. 
This can be accounted for in most part by the larger tonnage obtained 
from the sunflowers. More experiments of this kind are necessary 
before definite conclusions are possible. 
VARIETIES. 
The principal variety of the sunflower now grown in the United 
States for silage purposes is the Mammoth Eussian. This variety 
usually has a single stalk with comparatively few branches and one 
head 6 to 12 inches in diameter. The seeds are approximately half 
an inch long and one-fourth to five-sixteenths of an inch wide. They 
vary in color from almost pure white to black ; most of them, however, 
are white with longitudinal streaks or bands of gray or black. The 
Mammoth Eussian is a vigorous heavy-stemmed variety with large 
leaves and produces heavy crops of seed. 
