Page 131 - Soil Degradation, Conservation and Remediation

4.7 Stabilization of Dunes 119

Fig. 4.9 Making straw checkerboard on dunes to stabilize them (Photo courtesy of Michael Reynolds)

shows the efforts of stabilizing sand dunes with wheat straw checkerboard to be
followed by vegetation in Ningxia, China. The Autonomous Region Ningxia people
have been combating against deserts and rolled them back by dwindling sand areas to
1.18 M ha from 1.65 M ha since the 1970s. At present, 470,000 ha of desert has been
tamed by fixing sand with nets of wheat straw and planting drought-resistant plants.
Ningxia is located in an arid and semiarid area. Straw mulching enhances cryptogam
colonization and increases microorganism numbers, which are related to the forma-
tion of cryptogam crusts (Li et al. 2000). It increases the survival rate of shrub
seedlings due to reduced soil erosion (Li et al. 2006) and as litter provides nutrients
by decomposition (Hu and Zhou 1991). To date, the approach of using straw checker-
boards and revegetation has been successful and effective for controlling mobile
dunes and rehabilitating desert ecosystems (Fullen and Mitchell 1994; Whitford
2002; Li et al. 2004). Straw checkerboard and vegetation can be integrated. Figure 4.10
shows stabilized sand dunes in southern Saskatchewan, Canada.

Study Questions
1. Wind erosion is a problem of the arid and semiarid regions – why? What are the causes
of accelerated wind erosion? What are the on-site and off-site effects of wind erosion?
2. Describe the processes of wind erosion. Mention the principles of wind erosion
control.
3. Narrate the cover crops, grass barriers, and windbreak as wind erosion control
measures.
4. Discuss residue management, stabilization of soil, and mulching in relation to
wind erosion control.
5. What are dunes? Why should they be stabilized? Discuss the vegetative measures
for dune stabilization.