The Weeds of Arable Land in relation to the Soils 
on which they grow. 
BY 
W. E. BRENCHLEY, B.Sc, F.L.S. 
Lawes Agrictiltural Trust , Rotha?nsted. 
UR TNG the last fifty years a considerable amount of work has been 
U/ done on the various species of plants which are to be found associated 
in grass-land. The relations existing between the plants and the soil on 
which they grow have been well investigated, while the effects of different 
manures on the growth of the different species have been exhaustively 
tested at Rothamsted, the permanent experiments to this end extending 
over a period of fifty-four years. 
While so much is known about grass-land vegetation, our knowledge 
of the relations existing between the weeds of arable crops and the soil 
on which they grow is more or less indefinite and vague. Many observers 
have recorded their impressions and observations, 1 but these have never 
been so tabulated and reduced as to give the information required in a 
systematic form. 
This being the case, an attempt was made in the spring and summer 
of last year (1910) to devise some means of finding out how far the weeds 
of arable land are characteristically connected with particular soils and crops, 
and how far they are independent of either soil or crop. 
As a beginning it was decided to limit the work chiefly to the soils 
overlying the well-defined geological series of rocks between Harpenden and 
Bedford, where within about twenty miles the Chalk, Gault, Lower Green- 
sand, and Oxford Clay appear in well-marked succession. The bulk of the 
work ultimately centred in the Bedfordshire districts round Dunstable 
(Chalk), Harlington (Gault), Flitwick (Lower Greensand and Oxford Clay), 
and Woburn (Lower Greensand and Oxford Clay). Some investigations 
were also carried on near Hertford and Hitchin (Hertfordshire). 
1 ‘ On the Indications which are Practical Guides in Judging of the Fertility or Barrenness of the 
Soil.’ By John Bravender. Journ. Roy. Agric. Soc., vol. v, 1845, pp. 567-78. 
‘On Agricultural Weeds.’ By Professor Buckman. Journ. Roy. Agric. Soc., vol. xvi, 1855, 
pp. 359 - 81 . 
[Annals of Botany, Vol. XXV. No. XCVII. January, 1911.] 
