1. Introduction
The use of soil as a raw material to make bricks is a traditional and conventional form of building construction in China. With the increased requirement for bricks due to rapid economic growth and the continued expansion of urban areas, large numbers of brick kilns were established throughout the country in the last two decades. The use of soil materials for making bricks not only contaminated the environment (Zhang, 1997), but also occupied a large area of land. In addition, removal of surface soil for brick making resulted in substantial areas of abandoned low quality land. In the low hill areas of southern China, there are deep, moderate textured red soils with low elevation, good rainfall and