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the soil. pXua vegetation will be able to retdn moet of it
on site. Sopper (1975) oonoluded that use ofN fertilizers
leads to only temporary increases in the N cmtent of run-off
wtter, Phosphorus and other elements [Ire lost in drainage
water f rm poat lands particularly aft ur fertilization with
soluble phosphates am et al., I 974). The latter zuthors
also express concorn th2t increased fertilizer use could lead to
marked chcnges in soil and wator acidity,
iii) Removal of nutrients in tirabor
m n g the past 80 years or so, and particularly during the
past 20 yecra, numerous dutc have been coUscted on the amounts
of organic mtter and nutrients in the various parts of tmes
of a various species grow5ng under a ~ d range e of site conditions
(@in& on, 1 962; Rede, 1 956; Rodin & Bazilevich, I 967).
Ovjngtonls (1959a, 1959b) study of Scots pine is one example of
this type of work (?able 5). He felled a soriss of sam2le
trees of different ages all growing on virtually the same soil
type and in the sane area and measured the wights and chelnical
composition of their cmp~nent pa*s.
roots, needle fzll and on the soil,
He also gathered data. on
He ws then able to estimte
the rates of accumula.tion of nutrients in different parts of
the tree and in plant remains as v~ell as changes in the soil with
time.
For comparison with the tree aata, we have assembled data on
inputs of nutrients in precipitation (~abla 5). These are
of the same order ns values &ven in Table 3 for Moor House
and published data for othsr pwts of Britain, (~gner&
Eriksson, 1958/.t959; Madgvfick & Ovington 1959).