SUDAN GRASS.

H. N. VINALL, Agronomist, Office of Forage-Crop Investigations, Bureau of Plant Industry.

CONTENTS.

Page. Origin of Sudan grass 1 Description of Sudan grass 2 Climatic requirements : 5 Drought relations 6 Soil requirements 6 Place in the cropping system 7 Value in irrigated regions 8

Page. Sudan grass and legume mixtures 9 Culture _— 10 Utilization 15 Seed production 19 Diseases of Sudan grass _ 22 Insect enemies of Sudan grass 24 Improvement of Sudan grass 25

ORIGIN OF SUDAN GRASS. DOUBTLESS Johnson grass would be a much more valuable hay

plant for the Southern States if it were not equipped with vigor- ous underground stems. Eecognizing this fact, systematic search for forms of andropogons lacking these aggressive rootstocks was begun under the direction of C. V. Piper, Agrostologist in Charge of

the Office of Forage-Crop Investigations. With the assistance of the Office of Foreign Seed and Plant Introduction, 8 ounces of seed of a grass known as garawi was obtained on March 15, 1909, from Mr. E. Hewison, Director of Agriculture and Lands of the Sudan Govern- ment at Khartum.1 A portion of this seed was planted at the Forage-

Crop Field Station, Chillicothe, Tex.,2 that spring. The grass proved

1 Piper, C. V. Sudan grass, a new drought-resistant hay plant. U. S. Dept. Agr., Bur. Plant Indus. Cir. 125, 20 p., 6 flg. 1913.

Oakley, E. A. Some new grasses for the South. In Yearbook, U. S. Dept. Agr., for 1912, p. 495-504, 6 pi. Vinall, H. N., and Getty, R. E. Sudan grass and related plants. U. S. Dept. Agr. Bui. 981, 68 p., 25 fig. 1921. (This bulletin contains a detailed account of the intro- duction of Sudan grass and several other species of grass sorghums, as ;vell as a sum- mary of the results of numerous experiments with Sudan grass in the United States.)

2 The field station at Chillicothe, Tex., is maintained as a cooperative project in con- junction with the Texas Agricultural Experiment Station. From its inception, in 1905,.up

to 1916 the expenses were borne largely by the United States Department of Agriculture. In 1915, 100 acres of land 5 miles southwest of Chillicothe were purchased by the State of Texas and designated " Texas Substation No. 12." The cooperation between the Office of Forage-Crop Investigations of the United States Department of Agriculture and the Texas Agricultural Experiment Station has been continued at the new location. The administration of the station since January 1, 1916, has been in the hands of the Texas station, and the State of Texas has made liberal financial contributions to support the work. An account of the trials of Sudan grass at the State substations throughout Texas is given in Texas Agr. Exp. Sta. Bui. 172.