Spatial Variation of Organic Matter in Horizontal Zonal Soils in China

Spatial variation of organic matter content and humus HA/FA in horizontal zonal soils in China is studied based on the data obtained from the second national soil general investigation The results suggest: 1) Indicated by organic matter property, yellow brown earth zone is a unique zone in latitudinal zonal soil spectrum 2) Organic matter content and its variation range decrease from east to west in longitudinal zonal soil spectrum Soil organic matter content in warm temperate zone is higher than that in its neighboring temperate zones, higher soil humus HA/FA and its bigger range results from the middle temperature and moisture conditions and moderate human influence 3) Appropriately influenced by human activities, organic matter content of fertile soils usually decreases, while that of infertile soil increases, however both of them have a higher HA/FA 4) Soil ecosystem has the different ways of preserving organic matter For example, the accumulation amount of organic matter is bigger in Northeast China, the forming speed of organic matter is fast in Southeast China, while the soil humus HA/FA or the relative content of inactive humus and humin is bigger in Northwest China