322 BULLETIN OF THE BUSSEY INSTITUTION. 
tice, as I am satisfied by facts which have fallen under my own 
observation. Indeed, I can report some tolerably definite experi- 
ence upon this point also. In the year 1870, when the Bussey In- 
stitution was organized, the ‘+ Plain-field”’ upon which the school- 
building now stands carried a crop of rye, as it undoubtedly had 
done at intervals in previous terms of years, since rye in alterna- 
tion with grass was a favorite crop upon the farm; and the field had 
doubtless received meanwhile dressings of dung that contained 
charlock-seeds. At all events the soil of this field, when it fell to 
my charge, was — like the rest of the farm — full of charlock-seeds. 
During the years 1871-74 a good part of the Plain-field was coy- 
ered with experimental plots of which only those devoted to 
barley * were favorable for the growth of charlock. Upon the 
barley plots this weed grew in abundance. In the autumn of 1875 
the whole field was laid down to grass, with artificial fertilizers, 
but without any addition of stable-manure or compost. During the 
first year or two after the seeding, that is to say in 1876 and 1877, 
a good deal of charlock appeared among the grass plants, but they 
were persistently pulled up and carried away before their seeds 
could ripen, and finally when the sod became thick and firm with 
June grass it appeared that the charlock had been effectually 
‘*smothered.” But although charlock-plants no longer appear 
among the grass of this field it is none the less true that the soil is 
still full of vigorous seeds of the pest. It is only necessary to 
break through the sod and to turn up some of the soil in order to 
have an abundant crop of charlock spring up in the course of a few 
days or weeks. ‘This experience has been had anew each year on 
the occasion of planting trees and shrubs in different parts of the 
field and has been noted with no little interest. I have myself no 
doubt that charlock-seeds which were buried in the soil as long ago 
as 1875, and many that were probably shed at a much earlier 
period, are now (1881) perfectly vigorous and ready to avail 
themselves of the first chance to germinate which is offered when 
the soil is stirred. Iam well aware that the time which has elapsed 
since this particular observation began is, comparatively speaking, 
short and I have no doubt that many farmers can recall from their 
own experience instances where an abundance of charlock has 
sprung up on their fields after it had been smothered by grass dur- 
ing a much longer term of years. But I suppose that in such 
* Compare the first volume of the Bussey Bulletin. 
