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The effect of tre-g varies with age, size, and. breed of animal
involved, more specifically with hoof area, the pressure exerked
on each hoof, the nursber of times, and the viay in which the hoof
is applied to the ground per unit area and per unit time, and the pattarn
of moveaent of the &Lima1 within an wea.
The fm data available for hill breeds and conditions and -extra-
polation from data for lowlands, indicate that cattle tmad twefour
thos more he-lviu than sheep, and their stride ad
am;& are respectively three and four times @eater.
truvel about the same distance per day, around 2-5 km.
hoof contact
Sheep and cattle
Such data
suggest that, with the level. of stocking camonly found in MU1 mas,
0.2-1.0 sheep ha-' or 0.2 cattle ha', -h of the pasture is tmmpled
several times per year, Because of vegetation variation, food
selection, and tho chara.cteristil?s of diurnal and sensorial movement
of animis, trampling is ooncentrated on areas of more patdtable
vegetation, 9.g.
w-Festuca, or on muoh-used paths.
Trampling muse soil ompaction and aisturbance and damage to the
vegotztion but may also be beneficial by areatkg new sites for
ea%ablishment of seedlings, by f idng seeda h the soil and by
prom&%
tillering.
Soil oornpaction is conoentrated in the top few cms., of soil and i s
gmatesh, on soils rich in clay, organic matter and moisture and lea&,
on the aell-dra5nad sandy and stony soils, It brdsto changes in
soil characteristics such as aeration, root pene$rabiEty, infiltrp tian
rate, and thermal ~h~ractexistics, all of Mch cm affect soil
- fertility and vegetation composition or performance.
rn
Small agficultural vehicles exert;' similar pressures to those oaloulated
for animnls and their passage has simil-r ef i'ect s to those of animal
tmmpling, but is concentr~ted more on established tmcka,