Weeds. 
223 
rule, enormous quantities of small seeds, and many, like the 
annual Poa and the common chickweed seed from early spring 
till late autumn. If it were possible to cut them down before 
the seed is produced little would be gained, for the life of an 
annual plant is maintained until it bears seed. In this way the 
annual mignonette is converted into a shrub by the gardener, 
but whenever he permits it to flower and fruit it dies. In the 
same way the annual wheat would keep possession of the ground 
for years, though the popular notion that in time it changes into 
oats is baseless and absurd. 
Efficient cultivation, as in the case of root crops, removes the 
annual weeds. But this cannot be done in cereal crops. 
When harA^est opens up the weeds to the influence of the sun 
they become active in the production of seed. To prevent this 
it Avould be well, where it is possible, to run a shalloAV plough 
OA'er the field so as to turn over the weeds and arrest their 
activity ; and Avhen the deeper ploughing is done later the 
Avhole of the surface vegetation would be so buried that it 
would be destroyed. It is obvious that the rotation of crops 
affords, in its courses, several opportunities for dealing with 
weed pests. 
To deal efficiently with perennial Aveeds in good pastures is 
a serious problem. There is a great and general dislike to break 
up an old pasture because of the difficulty of procuring within 
a reasonable time a good turf. In these days, Avhen the value 
of the various plants in a pasture is better known, and the 
poAver to obtain true and clean seed of high germinating quality 
is within the reach of every one, this danger no longer exists. 
There are, moreover, many erroneous opinions as to the desir- 
able or objectionable elements in a pasture. The A^alue of some 
good pasture lands in France was believed to be due to the 
abundance of crested dogstail. The seeding heads of that grass 
appeared from their great abundance in autumn to establish 
that they were the cause of this high quality. But it is clear 
that a grass which is alloAved to run to seed could not have been 
eaten by the stock, and that the real value belonged to the close 
cropped grasses, other than the dogstail, which were scarcely 
visible. So also the late distinguished scientific agriculturist. 
Sir John B. Lawes, Bart., who cannot be charged Avith careless 
observation, came to the conclusion that rye-grass, which 
abounded in some good pastures in Hertfordshire, gave to them 
their high feeding value. He had a plot in one of these fields 
hurdled in, where he observed that rye-grass predominated. 
To his astonishment the rye-grass disappeared and cocksfoot, 
meadow-fescue, and foxtail overpowered all else. His first 
conclusion was that a pasture should be regularly eaten down 
to prevent the coarser grasses getting the mastery over the finer 
