Page 128 - Soil Degradation, Conservation and Remediation

116 4 Wind Erosion

Fig. 4.7 Perennial grass barriers for wind erosion control (Photo courtesy of USDA-NRCS)

4.6.5 Wind Barrier

Barriers reduces wind erosion by (1) reducing the field width, (2) reducing the
distance that wind travels in crossing unprotected field strips, (3) decreasing wind
velocity, and (4) trapping wind-blown and saltated soil. Use of wind barriers is an
effective old wind erosion control measure (Bates 1911). Different combinations of
trees, shrubs, tall-growing crops, and grasses can reduce wind erosion. Besides the
more conventional tree windbreak (Read 1964; Ferber 1969; Woodruff et al. 1976),
many other barrier systems are used to control wind erosion. They include
annual crops like small grains, corn, sorghum, Sudan grass, sunflowers (Carreker
1966; Fryrear 1969; Hagen et al. 1972), and tall wheatgrass (Black and Siddoway
1971; Aase et al. 1976) (Fig. 4.7). Most barrier systems for controlling wind erosion,
however, occupy space that could otherwise be used to produce crops.
Typically windbreaks are linear plantings of single or multiple rows of trees or
shrubs in boundaries of crop fields and farm holdings (Fig. 4.8). They are arranged
usually perpendicular to the direction of the prevailing wind. They reduce the velocity
of the wind at the ground level to a distance approximately ten times of the height
of plants. Winter wheat, barley, rye, alfalfa, vegetables, and fruits can be successfully
grown when fields are sheltered with windbreak. Sudmeyer et al. (2007) suggested
that windbreaks of trees, or tree and shrub combinations, can offer many benefits on
wheat belt farms, in addition to protection of soil, stock, crops, and pastures.
Perennial barriers grow slowly and are often established with difficulty (Dickerson
et al. 1976; Woodruff et al. 1976). A list of shrubs and trees suitable for windbreaks
is given below.
Shrubs: American cranberry bush (Viburnum trilobum), dogwoods (Cornus sericea),
(Cornus racemosa), (Cornus alternifolia), (Cornus amomum), silky elderberry