SWEET CLOVER 
829 
the seed coat so that moisture can get thru. 
Several schemes for reducing the loss 
due to difficult germination have been tried 
with varying success. 
In the national bulletin on sweet clover 
directions are given for soaking the seed in 
commercial concentrated sulphuric acid for 
half an hour, a plan which has been suc¬ 
cessful, altho somewhat dangerous. The 
acid eats away the impermeable seed coat 
sufficiently to enable the seed to absorb 
enough moisture to germinate. Tests made 
in the Department of Agriculture gave an 
increase in germination of 40 to 45 per 
cent. 
After the acid is poured off, the seed 
should be quickly washed, using running 
water if possible, as sulphuric acid becomes 
very hot when mixed with a small propor¬ 
tion of water. The seed should then be 
dried out quickly by spreading it on a 
board or canvas and stirring at intervals 
of two or three minutes. 
Since sulphuric acid burns flesh and 
wooden objects, great care should be taken 
in working with it. Vessels used for treat¬ 
ing the seed should be of earthen or 
enameled ware. 
After testing, seed should preferably be 
planted at once, as it has a tendency to 
dry out. Where the air is not too dry, 
however, it may be held two weeks or a 
month if necessary. 
SCARIFYING MACHINE. 
A new but highly promising method 
consists of scratching sweet clover seeds 
in what is called the Ames hulling and 
scarifying machine, brought out in April, 
1915, by the Iowa Experiment Station. By 
its use the germination of legume seeds is 
reported, after extensive tests, to be in- 
increased to over 90 per cent. 
The first machine of this efficiency was 
constructed in December, 1913. No an¬ 
nouncement was made at that time, how¬ 
ever, in order to allow time for field tests, 
comparing treated and untreated seed, in 
addition to extensive germination tests. 
A large number of plots were seeded on 
the station field in 1914, comparing treated 
and untreated sweet clover seed from vari¬ 
ous sources. In a large number of cases, 
stands which were, if anything, too thick, 
were secured from the treated seed, when 
the same seed planted at the same time, 
but not treated, failed to produce any stand 
at all. 
The machine as constructed has a capac¬ 
ity of approximately 25 bushels per hour, 
and requires about four-horse power to op¬ 
erate it. It is estimated that it can be put 
on the market at a price not to exceed $90 
to $100. 
The construction of the machine repre¬ 
sents eight years’ work on the part of 
H. D. Hughes, Chief of Farm Crops at the 
Iowa Experiment Station. 
During the spring of 1914 and 1915 
several thousand pounds of sweet clover 
seed were treated for individual farmers. 
A farmer for whom the station treated some 
3,000 pounds of seed in the spring of 1914 
states that the seed germinated approxi¬ 
mately 50 per cent when sent to Ames, but 
germinated 98 per cent when returned. 
Another reports using 5 pounds per acre 
of treated seed, from which he secured a 
perfect stand, while the usual rate of seed¬ 
ing ranges from 15 to 20 pounds per acre 
with many failures and uncertain stands 
resulting from poor germination. 
HOW MUCH TO SOW. 
The amount of seed to sow to the acre 
depends upon what purpose the sweet clo¬ 
ver is grown for. Moreover, the promising 
invention described above is likely to make 
necessary a revision of the estimates usually 
given. 
Not less than 20 pounds of unhulled seed 
and not less than 12 to 15 pounds of the 
hulled should be sown to the acre. Ordi¬ 
narily 20 to 30 pounds of the hulled and 
5 pounds more of the unhulled are advised. 
For sowing on waste lands, about one 
bushel to six acres is enough. Altho the 
plant spreads rapidly, it is well to sow 
enough to insure a good stand. To secure 
continuous growth, sow the second year 
also. 
Can sweet clover be gotten rid of after 
a crop has been grown, and small grains 
sown the next year? This is a question 
which has worried farmers wherever the 
plant is being introduced. One reported 
that he had planted wheat the spring fol¬ 
lowing a crop of sweet clover in the same 
field, and that the clover has choked out the 
