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laboratory incubation studies, compared the release of
nukrients frm (A) pl--it zakeri-1 cut in October and (B) fc*
ous produced by sheep fed the same mterials cut at monthly
intervals Prom May to October. He found that readily
available nitrogen (N), inchding urine N, increased from
31.5 for A t o 52.7 kg ha-' for B for krcstia-Fesf uoa
a d 12.0 for. A to 18.4 for 3 kg nal for Nardus in spite
of herbage producLion decreases of 6% for A and 24% for B.
Similar reault s were found for phosphorus (P)-
He also
demonstrated increased uptake of N and P fim dung and urine
by the pasture plants,
Clearly, gr~zing speeds up the
nutrient circulation in the surfaca soil./vegetatiun system
and this more rapid re-use of the small amounts of available
nutrients present in hill soils can be interpreted aa an
jndication of improved soil fertility,
In his fence-line study, Floate (1972) found that grazing led
to:
i) Reductions in the ratios of c.rrSon (c) to N and P for phnt
rewins and of soil to 4O cm depth. Such ratio& are
often thought of as indicatcrr s of soil fert;iUty.
a) Increases, in b &la total and organic P but no significant
ohange in the concent ration of available P in the top 40 cm
iii) mPn herease in soil pK but not in base saturation,
Howard & Howard (1 976) recorded higher nitrogen cronteflts and
a lower C/N ratio in the top 3.5 cm of eoil Kith grueingn
bspi rntory actidty of the soils was higher on the ungmz#d
area, probably as a result of conversion of herbage to faeces
with a lower mspiratory activity (Floate, 1970). During
& Radoliffe (1962) found th~t the top 4 cn of the duneenriched
soil of sheep-tmcks on hills In New Zealand had is. higher C