321 TJic Improvement of Grass Lands. 
far more advisable to improve the existing turf, for there seems 
to be something with regard to permanent pasture, especially on 
stiff soils, that is not obtained in recently laid land. Whether 
this is attributable to the accumulation of vegetable matter 
making the grass better, or to something repellant in the soil of 
a newly laid field, 1 am unable to determine. Whatever the 
cause, the grasses do not do well after the first three or four years, 
for the succeeding eight or ten they appear to decrease in vitality, 
and subsequently begin again to improve. If the soil is light 
and in good condition, this dormant state only extends over a 
year or two ; but on very stiff poor soils it takes years before a 
good permanent pasture is obtained. The most satisfactory reason 
for this that I have met with is that mentioned by Mr. H. S. 
Thompson in vol. xix. (p. 259) of the Society's Journal, that 
" All the gramineae that are of value for grazing or mowing 
require a fine tilth or mould as a condition of their successful 
cultivation. For the first year or two after strong land has been 
laid down it retains to some extent the porous texture induced 
by the thorough disintegration which it received in course of 
preparation for sowing. The second winter, however, generally 
obliterates all traces of previous cultivation, and the close and 
sodden state of the land which then supervenes is highly un- 
favourable to the growth of grass. The land may contain a 
sufficient supply of all the elements of plant-nutrition, but they 
are in a crude state, and a constant supply of oxygen is required 
to promote the decomposition of the mineral and vegetable 
matters, and their re-combination in forms available as plant- 
food, so that if air and water cannot easily and quickly pass 
through the soil in repeated succession, a check is given to nature's 
under-ground cookery as completely as if the flues were stopped 
in the farmer's own kitchen, and the dinner had to be prepared 
without any possibility of lighting a fire. Hence the sudden 
falling off in the produce of newly laid grass on strong land, and 
hence the necessity at this critical period for an abundant supply 
of plant-food on the surface to compensate for the falling-off 
below." This compact and set state of the land is patent to 
every valuer who has gone over land with a spade and observed 
the difference in value between a field that has been only laid a 
few years and an old meadow. Another writer, the Rev. W. R. 
Bowditch, quotes Mr. Darwin (vol. xix., p. 225), as showing the 
accumulation of mould in old grass lands to be due to the 
castings of worms. Worms have undoubtedly a great influence 
upon meadow land, and are an assistance in breaking up that 
peculiarly compact state the land gets into after having been laid 
a year or two; and this breaking up would continually allow a 
more free circulation of the air. 1 am also told that the chief cause 
