18 Farmers' Bulletin 1126.

the market demands for Sudan grass seed become better established, the seed production will no doubt be centered in favored localities, as it now is for such crops as Kentucky bluegrass, timothy, orchard grass, vetch, and alfalfa.

The planting of Sudan grass for seed production has already been described. Harvesting the seed is accomplished most economically with an ordinary grain binder or a row binder. Harvesting with a row binder is illustrated on the title-page. When the seed is practically mature, Sudan grass can be cut and bound like grain and left to cure in shocks. It may then be hauled directly to the threshing machine or stacked in the same manner as bundle grain. There is danger in stacking Sudan grass, however, because the sap in the stems dries out slowly, and if stacked before it has cured thoroughly the grass will heat in the stack and injure the viability of the seed. Growers usually find it best, therefore, to allow the Sudan grass to remain in the shock until they are ready to thresh. The use of shock covers results in a much brighter, better quality of seed.

The ordinary grain separator threshes and cleans Sudan grass seed very satisfactorily. Care must be observed to so regulate the air blast as to prevent seed from being blown over into the straw pile. A clover huiler also has been used with success in threshing Sudan grass, but seed threshed in a clover huiler is likely to be rather completely freed from the hulls and therefore weighs much heavier than ordinary seed.

The weight of the seed varies from 25 to 40 pounds per bushel. Good clean seed should weigh 36 to 40 pounds to the bushel, and such seed will pass through the feed of an ordinary grain drill without clogging.

Seed sold at retail during the winter of 1913-14 at $1.50 to $2 a pound, and the farmers realized 50 cents to $1.50 a pound for their seed in bulk. At such prices seed growing was very profitable. Since 1916, however, the price received by the grower has fluctuated from 1| to 32 cents a pound for seed in bulk, and the retail price for this seed in producing sections has varied from 6 to 40 cents a pound. There is little profit in the production of Sudan grass seed when it nets the grower less than 6 cents a pound. The thrashed Sudan grass is said to have about the same feeding value as prairie hay.

The seed of Sudan grass resembles Johnson grass seed very closely, except that it is larger and more plump (fig. 10). No machinery for separating the two kinds of seed has been devised ; hence the only way of obtaining pure Sudan grass seed is to guard against its mixture with Johnson grass during the growing period and in the threshing process. South of 38° north latitude, indicated on the map shown as Figure 3, Johnson grass behaves as a perennial and is troublesome because it is difficult to eradicate. North of the thirty-eighth parallel of latitude, roughly speaking, Johnson grass is not troublesome, because it usually is killed by the winter freezes. A slight admixture of Johnson grass in the Sudan grass seed sown for hay production north of the thirty-eighth parallel is no great disadvantage. South of this line, where Johnson grass is likely to become a pest, care must be used to see that the Sudan grass seed is free from Johnson grass seed. %