30 Thirty-Ft1`fth Annual Report.
printed as a station circular. The discovery of self-fertile  
strains of clover should be of tremendous benefit in breeding _ 1
up strains of clover of great vigor and disease-resistance. l
Sweet Glover. Clipping tests on sweet clover to dete1·- `
mine whether or not clipping will kill or injure it at various
· stages of growth, indicate, so far, that little or no injury re- .
suits from clipping the first year. The plant has a crown dur-
_ ing the first season and a new growth starts promptly even
when the clover is cut very low. During the second year, we
have been unable to get any new growth after clipping at any
[ time or at any height where the stand was thick and vigorous.
There seem to be no buds on the stalk near the base and of
course the second year there is no crown from which the new
shoots could spring. lt is evident that the production of a
· seed crop after the growth has been cut for hay must depend
upon leaving some of the lower branches of the sweet clover
uncut. `Where the stand is very thin, this might be possible.
A series of clipping tests have been started in which the stand
varies from very thin to very thick, the object being to ascer-
tain if any kind of a stand can be clipped the second year and
a seed crop produced later.
Soils. One. very important feature in the results of the
work on soils is the difference in the behavior of acid phos-
phate and rock phosphate on limed and unlimed ground on
dift'erent soil types. The following data are presented to show
the wide variation in the effect of these two forms of phos-
phate. For example, on the Mayfield experiment iiehl, the
rock phosphate is quite as effective as acid phosphate on both
limed and nnlimed soil, while on the Campbellsvillc field, the
other extreme is found in that rock phosphate is very effective
on unl ilmed soil and very ineffective on limed soil. An interest- .
ing observation is that as the experiments grow older the
depressing eHect of limestone on rock phosphate becomes
greater where there is a depressing effect at all.
lt is probable that the ideal condition for the use of rock
phosphate is a neutral soil. In practise this would mean that