ABSTRACT
Introduction According to the FAO Land and Plant Nutrition Management Service, saline-affected soil covers over 400 Mha, which is over 6% of the world land area. Most saline soil lies in dry regions, including North America, South America, Australia, China, Russia, India, Med. Area, Middle East and Southeast Asia. In China, Songnen Plain, one of the three largest sodasaline regions in the world, is a representative region with characteristics of high Na+ and Na2C 03, high pH value, high alkalinity, and poor physical and chemical properties. A recent inventory concluded that the area of highly saline soil is increasing by 1.4% per year ( Li Xiujun et. al. 2002; Li Qusheng et.al. 2001), which reduces the output of fertile land, degrades the quality of grassland and deteriorates the ecological environment.
