PROCESSING SEED OF GRASSES AND OTHER PLANTS 7h 
: : 28.5 
in test weight per bushel ( 58 
=4.91), This decrease in volume 
materially facilitates storage and handling. The cost of processing 
averaged 97 cents per 100 pounds at 600 r. p. m. and full rate of feed- 
ing. When all the data are carefully considered, it is evident that 
seed of Canada wild-rye can be successfully deawned at low cost if 
the speed, rate of feeding, and size of screen used in the mill are deter- 
mined. The improvement made by processing this seed can be seen 
by comparing the unprocessed and deawned seeds in figure 1. It is 
clearly evident that processing greatly facilitates handling. 
DaTA ON SEVEN GRrRassES DEAWNED AT OptTiIMuM OPERATION 
oF MILL 
Following the procedure used in deawning Canada wild-rye, trials 
were conducted with seed of six other awned grasses. The replicated 
determinations of proper mill speed, rate of feeding, size of screen, 
and tests subsequent to processing are not presented. Table 3 gives 
for the several grasses the averages of the three trials in which the 
mill was operated at optimum speed. 
MILL SPEED AND SIZE OF SCREEN 
Milling to remove the awns from grass seed was successfully ac- 
complished with all species (figs. 1-6) when the correct speed of 
cylinder and size of screen were determined. Only one rate of feeding, 
that required to operate the mill at capacity, was used with all species 
for which data are presented. The limits for mill speed with grass 
seed of different species range between 590 and 800 r. p. m. and can be 
determined within 50 r. p.m. The desired final degree of awn removal 
can be obtained by attention to mill speed irrespective of the per- 
centage of seed deawned by threshing before processing. The per- 
centage deawned before processing was found to have no effect on 
the method of milling but influenced the rate at which milling could 
be done. 
The percentage of seed deawned after the processing fell below 93 
percent for only tall oatgrass. When the mill was operated between 
600 and 800 r. p. m. the percentage of tall oatgrass seed deawned was 
too low to be satisfactory, and at higher speeds the amount of injured 
seed was too great. A mill speed of 720 r. p. m. gave 20 percent of 
deawned seed and 35 percent hulled, with less than 1 percent injured. 
This product failed to flow through a drill satisfactorily. Conse- 
quently the awned fraction was scalped off and milled a second time. 
Both fractions were then combined, cleaned, and tested. After this 
second milling, 86 percent of the seed was deaw ned; 36 percent was 
intact, and 50 percent was hulled. Less than 3 percent was injured in 
processing. As the data in table 3 show, the quality of the seed was 
improved. (See fig. 2.) 
It was also necessary to process bulbous barley twice in order to 
obtain the desired degree of awn removal and hold injury to a mini- 
mum. After this seed was milled once, about 30 percent was still 
awned. This fraction was recovered by running the product from the 
