Wind Erosion in New Zealand
L.R. Basher and D.J. Painter
Abstract
Aeolian processes have had a major influence in shaping the New Zealand landscape.
Contemporary wind erosion affects 13% of New Zealand, mostly in seasonally dry, eastern
regions where strong foëhn winds occur frequently in spring. Wind erosion has a severe
impact both on rangeland with poor vegetation cover and cropland. Wind erosivity in New
Zealand is relatively high by world standards, but the frequency of very dry surface soil
conditions is relatively low.
Few quantitative measurements of contemporary soil loss from wind erosion are
available. Rates of wind erosion have been determined from direct measurement of
short-term fluxes of material being transported by wind, post-storm measurements of soil
loss in severe wind erosion events, and indirect assessments using the caesium-137
technique. Measured rates range from a background of <0.1 t/ha/yr to storm event losses
of >3000 t/ha.
The main techniques used to control wind erosion are establishment of windbreaks,
forest planting, and improvement of vegetation cover on rangelands. Tillage practices
(e.g. direct drilling, crop residue management, seedbed preparation to maintain surface
roughness, larger aggregates and soil moisture content) and strip cropping are rarely
used. Wind erosion control schemes have been established in eastern regions of both
islands. Little is known of the economic cost of wind erosion in New Zealand. |
