Figure 14.11. Field shelterbelt reduces wind erosion and evaporative
Figure 14.12. An experiment with wide-spaced poplar trees planted in a
demand and increases landscape biodiversity.
New Zealand pasture to reduce landslide risk.
no-till, cover cropping, and perennial rotation crops.
SOURcES
In addition, practices that increase roughness of the
American Society of Agricultural Engineers. 1985. Erosion and Soil
soil surface diminish the effects of wind erosion. The
Productivity. Proceedings of the national symposium on erosion
and soil productivity, December 10–11, 1984, New Orleans.
rougher surface increases turbulent air movement near
American Society of Agricultural Engineers Publication 8-85.
the land surface and reduces the wind’s shear and ability
St. Joseph, MI: Author.
to sweep soil material into the air. Therefore, if fields
Edwards, W.M. 1992. Soil structure: Processes and management.
In Soil Management for Sustainability, ed. R. Lal and F.J.
are tilled and cover crops are not used, it makes sense
Pierce, pp. 7–14. Ankeny, IA: Soil and Water Conservation
to leave soil subject to wind erosion in a rough-tilled
Society. This is the reference for the Ohio experiment on the
monitoring of runoff.
state when crops aren’t growing. Also, tree shelterbelts
Lal, R., and F.J. Pierce, eds. 1991. Soil Management for Sustain-
planted at regular distances perpendicular to the main
ability. Ankeny, IA: Soil and Water Conservation Society.
wind direction act as windbreaks and help reduce
Ontario Ministry of Agriculture, Food, and Rural Affairs. 1997.
evaporative demand from dry winds (figure 14.11).
Soil Management. Best Management Practices Series. Available
from the Ontario Federation of Agriculture, Toronto, Ontario,
They have recently received new attention as ecological
Canada.
corridors in agricultural landscapes that help increase
Reganold, J.P., L.F. Elliott, and Y.L. Unger. 1987. Long-term effects
landscape biodiversity.
of organic and conventional farming on soil erosion. Nature
330: 370–372. This is the reference for the Washington State
Finally, a few words about landslides. They are
study of erosion.
difficult to control, and unstable steep slopes are best
Smith, P.R., and M.A. Smith. 1998. Strip intercropping corn and
left in forest cover. A compromise solution is the use
alfalfa. Journal of Production Agriculture 10: 345–353.
Soil and Water Conservation Society. 1991. Crop Residue Manage-
of wide-spaced trees that allow for some soil stabiliza-
ment for Conservation. Proceedings of national conference,
tion by roots but leave enough sunlight for a pasture or
August 8–9, Lexington, KY. Ankeny, IA: Author.
crops (figure 14.12). In some cases, horizontal drains are
United States Department of Agriculture. 1989. The Second RCA
Appraisal: Soil Water, and Related Resources on Nonfederal
installed in critical zones to allow dewatering and pre-
Land in the United States, Analysis of Conditions and Trends.
vent supersaturation during prolonged rains, but these
Washington, DC: Government Printing Office.
are generally expensive to install.
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