10 BULLETIN 1174, U. S. DEPARTMENT OF AGRICULTURE. 
CLEANING SEED. 
Hungarian vetch seed as it comes from the thresher will contain 
more or less cracked seed, small straws, weed stems, chaff, and the 
small grain with which it may have been grown. Ordinary fanning 
mills and seed cleaners that usually are available on farms or at ware- 
houses will separate readily most of the foreign matter and trash 
from vetch. These machines will also separate quite readily the 
seeds of vetch and of oats or barley, but wheat and rye seeds are not 
so readily separated from vetch seed. Separation can be satis- 
factorily accomplished by the use of a gravity spiral seed separator, 
such as recently has come into general use in the various regions 
growing vetch seed. 
YIELD OF SEED. 
In comparison with common vetch and hairy vetch Hungarian 
vetch produces a heavy seed yield. At Corvallis, Oreg., it not only 
has given heavy yields of seed, but it has been a consistently good 
producer through a series of years. In Tables 2, 3, 4, and 5 are given 
the seed yields of Hungarian vetch when sown at different rates of 
seeding alone and in combination with oats and also when fall and 
spring sown. In Table 5 the yields secured in the various seasons 
from 1916 to 1921 are presented. The largest seed yields, ranging 
from 1,450 to 2,700 pounds per acre, have been obtained from fall 
seeding. The largest yield in the rate-of-seeding tests was secured 
from the planting made at the rate of 80 pounds of seed per acre. 
When Hungarian vetch was planted with oats at different rates of 
seeding the largest yield of vetch was secured from the seeding of 
100 pounds of vetch and 40 of oats, but in the seeding at the rate of 
80 pounds of vetch and 40 pounds of oats a larger yield of oats was 
obtained, though the vetch yield was smaller. The yields from 
spring planting, as given in Table 4, are small in comparison with 
those from fall planting. While Hungarian vetch has not given 
very large yields in spring plantings, it has done as well as any other 
vetch when planted at that season of the year. In addition to the 
plat plantings made at Corvallis in the fall of 1920, there was one 
increase field of 1-^ acres sown at the rate of 80 pounds of seed per 
acre. This was on what is known as " white land," which is consid- 
ered of decidedly inferior quality. This planting in the season of 
1921 yielded 2,099 pounds of seed, or at the rate of 3 If bushels per 
acre, calculating 60 pounds of seed to the bushel. 
INSECTS IN RELATION TO POLLINATION. 
During the seasons from 1915 to 1921 a series of experiments was 
conducted to determine the relation of the tripping of the flowers 
and the visits of insects to seed setting. By tripping is meant the 
forcing of the staminal column out through the keel or inner petals 
of the flower, such as would be accomplished by the visitation of 
certain insects. With many plants this process is accompanied by 
cross-fertilization. The flowers on plants inclosed in fine-mesh 
netting cages were counted, and a part of these were tripped artifi- 
cially, while the others were allowed to remain untripped. The 
results of these trials are given in Table 6. It will be noted that 
there was a considerable increase jn the percentage of pods set in the 
case of the tripped flowers, indicating that the tripping was beneficial 
to seed setting:. 
