Wind Erosion:
An International Symposium/Workshop

In China, there are 12 deserts or sandy lands. Deserts and desertified land together occupy 1.52 million km2 or 15.9% of China and this area is expanding at an estimated mean rate of 2100 km2 y-1. Desertification and wind erosion processes were investigated at Shapotou Research Station, Ningxia, on the south-eastern edge of the Tengger Desert. The station was established in 1956 to investigate methods of protecting the Batou to Lanzhou railway from moving sand. Procedures were adopted using an artificial ecosystem to convert areas with shifting sands with less than 5% vegetative cover to areas of fixed dunes with 30-50% cover.

Detailed field research was undertaken by the authors in 1990, 1993 and 1994. Two approaches were used to estimate dust accumulation. Short-term measurements were made using dust traps, while longer term (~ 40 years) deposition was estimated using aeolian deposits on a dune chronosequence. Dust accumulating over the study period clearly showed that May had the highest rates, with mean monthly deposition of 73.6 g m-2. Dune topography influenced accumulation rates, with the greatest deposition in traps located on the leeward slope and dune hollow. Over the 11 months (August 1993 to July 1994), average dust accumulation from five traps was 309.8 g m-2. Using the thickness of 'grey sand', average accumulations have been calculated, ranging from 1.30 to 1.87 mm y-1. Vegetation, especially shrubs, also strongly influenced dust accumulation. The mean rate of increase in deposition was 4 mm of 'grey sand' for every 10% increase in shrub cover.