Circular No. 558 
June 1940 * Washington, D.C. 
UNITED STATES DEPARTMENT OF AGRICULTURE 
Processing Seed of Grasses and Other Plants 
To Remove Awns and Appendages 
By Joun L. SCHWENDIMAN and Rouanp F. SacKMAN, assistant agronomists, and 
A. L. HAFENRICHTER, senior agronomist, UNaneen Division, Soil Conservation 
Service 
Page Deawning grass seed—Continued. Page 
PERO GUC EO ee ee eee 1 Data on seven grasscs deawned at opti- 
INTEEN OC Shears xe ees el ere ee ee ee eS 2 mum operation. of millese= 
1D) Cawiin es PTASS SCC Ces wet ee 4 Deawnine otherseeds sesso ate oe 13 
Effects of different mill speeds and rate of Relation of optimum mill speed to diameter of 
feeding in deawning Canada wild-rye Or OKO (IPS 3S ieee age a ee eee er 14 
FSTEOXG [aie ES ele eee ia Os ae ee ASS SUM MAR yao ee ee ne een eee en 14 
INTRODUCTION? 
The difficulty of using the ordinary machinery in planting seed with 
appendages that are not removed in the normal threshing operation 
has retarded the use of several valuable plants in general agriculture 
and in nursery plantings. It is frequently possible to eliminate these 
undesirable appendages by breeding, but this method of improvement 
may require several years. At the Pullman nursery, Pullman, Wash., 
the removal of appendages by mechanical means has been ’ demon- 
strated to be commercially feasible and has been accomplished with a 
minimum of injury to the seed in processing? seed of several of the 
native and introduced plants adapted to the Pacific Northwest. 
This processing has facilitated the use of these grasses, valuable for 
erosion control and moisture conservation, making it possible to plant 
them with grain drills. Over 8,000 pounds of processed seeds were 
used on farms, demonstration projects, and work areas of the Soil Con- 
servation Service in the Pacific Northwest in the spring of 1939, in- 
cluding 5,600 pounds of tail oatgrass, 900 pounds of Canada wild-rye, 
and 850 pounds of blue wild-rye. Although some small lots were 
1The methods reported in this circular were developed at the Pullman unit of the Nursery Division, Soil 
Conservation Service, to facilitate the regular nursery work, which is done in cooperation with the Wash- 
ington Agricultural Experiment Station and the Bureau of Plant Industry, U. S. Department of Agri- 
culture. 
2 The term ‘‘process’”’ as used in this circular includes both milling and c!eaning. 
209602°—40 af! 
