ANALYSIS ON THE CHANGES OF ORGANIC MATTERS AND THEIR INFLUENCING FACTORS OF TYPICAL BLACK SOIL AREAS IN SONGLIAO PLAIN

Based on the results of multi-objective regional geochemical survey in the south-central Songliao Plain during 2003-2008, the paper studies the distribution characteristics of organic matters in typical black soil areas, proposing that the organic contents in the typical black soil areas along Suihua-Harbin-Siping are characterized by latitudinal zoning distribution, with decreasing gradually from north to south. By analyzing the influencing factors of soil organic matters, it is considered that the parent material and soil texture are important basis for organic contents. The lacustrine sediments and soil with fine texture containing clayey components usually have high organic matter contents. Climate conditions such as temperature and precipitation are the key factors affecting soil organic matters. Low temperature and humid climate are conducive to organic matter accumulation. Human factors such as long cultivation, continuous cropping and fertilizer use can reduce organic content.