54 BULLETIN 981, U. S. DEPARTMENT OF AGRICULTURE. 
Table XX shows yields of 350 to 400 pounds of seed in the humid 
corn-belt States, while the average yield in the semiarid regions is 
only 250 to 300 pounds per acre. Seed produced in the latter region, 
however, is likely to be of better quality than that from the more 
humid regions. In arid regions where irrigation is practiced, yields 
of 1,200 to 1,400 pounds of good seed per acre are to be expected. 
An increased acreage of Sudan grass devoted to seed production 
in these irrigated sections would appear. justified as soon as a reliable 
market for the seed has been developed. 
Only a small acreage was planted in 1913, and owing to extensive 
advertisement of the crop the seed sold readily at retail for $1 a 
pound. Prices as high as $2.25 a pound were recorded near the close 
of the 1914 planting season. These prices stimulated seed produc- 
tion in 1914 and resulted in the large crop of that year. Unreason- 
ableness on the part of certain growers and seed dealers in expecting 
1913 prices for the large crop of 1914 caused a surplus to be carried 
over into 1915 and that winter the price dropped to 4 cents a pound 
wholesale. The producers of the seed received much less than this, 
and their discouragement resulted in a marked decrease in the 
acreage devoted to Sudan grass seed production in.1916 and 1917. 
A price to the farmer of 5 or 6 cents a pound for the seed is necessary 
to make seed production worth while under ordinary conditions, 
if the yields given in Table XX are representative of what may be 
expected in different parts of the United States. 
In determining the suitability of any given locality for Sudan 
grass seed production, the presence of Johnson grass (Andropogon 
halepensis) should be taken into account. The seeds of Johnson 
grass are very much like those of Sudan grass in size and general 
appearance. No mechanical method for separating the two kinds 
when mixed is known. It is highly important, therefore, that pure 
Sudan grass seed be used on farms in the South where Johnson grass 
is not present. Johnson grass is a dangerous pest only where it 
behaves as a perennial. That portion of the United States where 
Johnson grass ordinarily lives over winter is shown on the map 
(fig. 13). Broadly speaking, the region in which it perennates lies 
south of 38° north latitude except for that area west of the Cas- 
cade and Coast Ranges in California, Oregon; and Washington. 
Outside of the district described Johnson grass behaves normally as 
an annual and can be easily killed out. Admixtures of Johnson 
grass seed in Sudan grass seed sown north of 38° north latitude is 
not a matter of any great importance when the crop is to be har- 
vested for hay, because it can be easily controlled and it does not 
injure the Sudan grass hay crop appreciably. 
It is well for those living in that section of the United States 
where Johnson grass perennates to remember: (1) That a farmer 
