THE RE-AFFORESTATION OF HAINHAULT. 19
herbage. Experiments8 were, however, made on staked out
strips on the lower half of Lockwood's 35 acres, on the
30 acres at the bottom of Dog Kennel Hill and on
Little Cabin Hill (three fields representing entirely different
types of soil), with basic phosphate and superphosphate
of lime, and also with potash in the form of kainite
and nitrogen in the form of sulphate of ammonia. On
Lockwood's land none of the manures had the slightest effect,
for where the physical conditions of aeration or moisture are
unfavourable, the supply of plant food cannot possibly affect the
crop. On Little Cabin Hill the result was no better, probably
in this case owing to there being nothing but Soft Brome-grass
to take advantage of the treatment, and only on the 30 acres at
the bottom of Dog-kennel Hill did the herbage respond. Here
basic-slag produced by far the best effect. It may be pointed out
that potash is present in considerable quantities in nearly all
Essex soils, so that a useful effect from its application was not
anticipated. The experiment with nitrogen manures had a
purely academic interest. Nitrogen always stimulates the strong
growing grasses which it was desirable to discourage and
weakens the clovers which it is desirable to stimulate. Such
accumulation of nitrogen as is desirable in the soil is provided
for by natural agencies, and especially by the growth of clovers
as nitrogen assimilating plants. The particular value of basic-
slag is that it encourages the clovers, and, therefore, indirectly
supplies such an amount of nitrogen as is needed by the
grasses.
Basic-Slag. While these experiments were in progress basic-
slag was applied to a part or the whole of the 40, 25 and
40 acres on Hog Hill, the 7 and 9 acres on Dog-kennel Hill,
Cabin Hill, Little Cabin Hill, and Lords Pond Fields.
Wherever slag has been put the result has been an increase in
the growth of White Clover and closer grazing by the cattle,
this latter being due apparently partly to the increase in clover
and partly to a sweetening of the herbage due to the excess of
lime in the basic slag. Most notable was the result on Cabin
Hill, where it could and can still be seen to a yard where the slag
has been spread. On the 40 acres sloping west on Hog Hill, a
dressing at the rate of 5 cwts. per acre of 30.34 per cent. slag
8 Carried out by Mr. B. W. Bull for the Essex Education Committee.