A COMPREHENSIVE METHOD OF EROSION RESISTANCE AND GROWTH PROMOTION FOR PISHA SANDSTONE

Abstract

Pisha sandstone is a special type of soft rock that is severely eroded by wind, rainfall, and
gravitational force. The surface of the area in the region consisting of this sandstone has been degraded as a
result of excessive human activities, and the vegetation cover in this area is extremely low. In order to
develop new methods to control further erosion and mitigate the adverse impacts of landslides, the material
components, nutrient contents and the shear strength of Pisha sandstone were studied and field experiments
via utilizing a new comprehensive method based on a hydrophilic polyurethane (W-OH) was carried out. The
results revealed that in Pisha sandstone the main minerals are quartz, feldspar, plagioclase, montmorillonite,
illite, and kaolinite. The montmorillonite was found to be the main cementitious material, however, is easy to
expand when meets water. The research also showed that the nutrient content is low, and the organic matter,
total nitrogen, total phosphorus, total potassium and available phosphorus corresponds to the sixth-level, the
nitrogen content corresponds to the fifth-level and the available potassium corresponds to the forth-level,
according to the six-level classification of soil nutrient content grading table. In the field experiment,
vegetation coverage rate in the treated area increased to more than 95% after 4 months, and shallow trenches
literally disappeared. The amount of sediment erosion was reduced by more than 90%, indicating that the
effect of erosion prevention and promoting vegetation growth is significant. A demonstration project of 0.2
km2 was carried out in Odors in 2015 by this method which has resulted in promising outcomes, and the
method has been widely accepted by the local community and soil conservation bureau.