西藏色季拉山土壤的性状与垂直分布

PROPERTIES AND VERTICAL DISTRIBUTION OF SOIL ON SHERGYLA MOUNTAIN IN XIZANG

色季拉山位于青藏高原的东南部,是西藏主要林区之一。由于气候和森林的垂直变化,其山体土壤类型的垂直带谱较为明显,基带为山地棕壤,往上依次为山地酸性棕壤、山地漂灰土、亚高山(灌丛)草甸土(黑毡土、棕毡土)、高山草甸土(草毡土)和高山寒漠土,并且东西坡呈对称分布。在分析了各类土壤的特征之后,讨论了土壤质地、有机质与养分、pH值、交换性能及化学组成的垂直分布规律。

Shergyla Mountain is situated in the Southeast Xizang and is one of the main forest zone in Xizang. By the changes of climate and forest,the vertical belts of mountain soil type are guite clear. There is the mountain brown forest soil at the base,and as the elevation rising,there are mountain acid brown forest soil, mountain bleached podolic soil, subalpine (shrubs) marshland soil,alpine marshland soil and alpine wilderness soil in proper order,and they are distributed symmetrically on the east and west slopes. The vertical distributionlaw of texture regime, organic matter and soil nutrient,pH or soil, composition of exchangeable and chemical comporition is discussed. The results are:1. Among the mount at 4 000 (3 700m east slope)-4 200m,there are clear podzolic layer, and the main cause to form is that the vegetation is thick, the air is damp, surface organic matter increases and the leaching action strengthens, then the most of Fe and Al runs off and the Si gathes.2. The vertical distribution of mount soil is clear,but the characters of each soil type are very different,for example,the organic matter make up 9 to 373g/kg,pH of soil expresses strong acid reaction to strong alkaline reaction, the base is saturated to not saturated highly. Especially podzolic soil,its many characters in the vertical distribution are very abnormal.3. At the same section, the regulars of each type soil in vertical distributtion are same almost. From top to deep soil,the characters of soil tend to primitive state,but the characters of podzolic soil are very different at the different places.4. The types of soil on the east and west slopes at the same elevation belt are identical basically and distribution symmetrically, but the characters of soil are different slightly. Generally, because that the rainfall is high and the growth of vegetation is well on the east slope, the appearance of leaching of soil on the east slope is more clear than on the west slope5. There is the special soil in same areas. By the difference with vegetation and condition of soil forming,the soil charactersare very different to the others at same belt.