Pisha Sandstone: Causes, Processes and Erosion Options for Its Control and Prospects

Pisha sandstone is a special kind of soft rock in the semiarid region along the up and middle reaches of Yellow River and Loess Plateau and is severely eroded by wind, rainfall and gravity force. Pisha sandstone region is called “the most severe water loss and soil erosion in the world” and referred to as the “Earth Cancer” by local residents and experts both at home and abroad. The plan for the control of Pisha sandstone started in the 1950s. Since then a series of projects have been implemented, both engineering and vegetation measures have been developed and widely used to protect Pisha sandstone from erosion. Since seabuckthorn was introduced as a viable approach for soil erosion protection and its implementation resulted in a breakthrough to control Loess Plateau, it was considered as an important and efficient measure. Then the seabuckthorn flexible dam was proposed for coarse sediment retention and fine sediment deposition. And then a new comprehensive control model using consolidation materials combined with vegetation was proposed and promising results were achieved both in laboratory and field demonstrations. In the future, the complex erosion mechanism and ecological carrying capacity should be studied further and more efficient and practical comprehensive measures shall be developed. Moreover, monitoring systems shall be used to predict and detect the changes in the Pisha sandstone slope and structure.