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In gener:r1, t!€e roots extond- to d. greator soil depth
tbs.n ao rcots of herbagc species (Douglass, 1967; tutter, 1968).
fhis iryfies that Bore Eator ana nutriedts are potentLo.lly
aveilcblc to trces than to herba6e spccier. In 3Jdition,
trees alpoer to be ablc to orploit nutrior* s in the
under]J.ing rock by ct vely etroo-r-6ing physical blcak up
aril cheidca]- weathexing jn the rootin8 zone ( ?p. 19 - ?9).
erazed upland pd3tur"cs, unLikc forest
accurulate a l-arge store of nutrients
systens, do not
in the stanaing vogetation
so their nutli.ent cycl-ing tonals to be faster than that in
woodlands, palticularry where aost of thei! pri!',ary prcductioo
is d.iverted into thc grizing criDa I ( pp. B - 1Z).
Both
for€sts ana Brassf.anas retuE) Iargs qua.btit:es of org&rlic natter
and nutriontr to the soil su!f.!ce :j.rrnu€ll-Jr and tlds return
tends to coLmteract th( leuching Lffect
of high rainfrll
larticulail-y in forests where nutrients t6nd. tc be brou8ht up fron
ihe deope r soil- or rock. Data given jlr lray & cor*ra$ (1964)
s.rld. Rodin & Bazilevich
(1967) togethe! suggest that ailowtd
of Litter-faL1 n@y be silrj.lar for both lanrl-uses in & given
clillatic zobo. The rates of decoi0positlon of J.eafy pLolt
l€Eains anC of releaso of tho containeal nutrients
appecr to be
high]-Jr rarlabl€ b1l6 of the salre ordor in forest and Erqssl.lnal
(Laiter & Cft\gi, 1967t l,ii,koLa, ,195{). Lj-Edn6, fortilizer.
adalitions a$d. incr€asetl stockirlg orr hil,l
pastur€s encoulsge
fast€r nutrient cycling r*lelEas the very slow alecoryosltion of
woodJr&"lerial iI1 foresis tends to r€ aral cycli-n€.
Both hil]-farrdng and. forestry can proiluoo changes ijl tho soi-1,
srrch as decruases i.11 the o!€ianic aatter o! nutrieBt cort 6nt
and irl availab],e nutricnts, w]rich nay be i-nter?teted as
aeterioratio!.
Ho1,lever, utleBs these changes lead to lates of
erosion gree.ter than the rate of soil
$ecessarily
of !l3-j or ix+ort.nnce.
for:Ft ion they arc nob