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 (i7, 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 jdeld of wheat on the corn plat's was 

 33.78 bushels and on the sunflower plats 28.36 bushels jDer 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 Russian. 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 Russian is a vigorous heavy-stemmed variety with large 

 leaves and produces heavy crops of seed. 



