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1·Once the humus layer disappears, nutrients cannot be recycled and leach from the soil, converting soil from fertile to infertile and making it suitable only for savanna vegetation.

一旦腐殖质层消失，养分就无法从土壤中回收和过滤，致使土壤由肥沃变为贫瘠，只适于热带草原植被的生长。

2·Humus layer in different forest types and soil surface type and quantity of soil fungal communities have a significant difference.

不同林型腐殖质层和土壤表层的土壤真菌群落种类和数量都具存在显著差异。

3·Main site factors in different groups of site type existed obvious difference, for instance the altitude, the thickness of humus layer and the slope.

不同立地类型组的海拔、腐殖质层及坡向等各主要立地因子存在着显著的差异。

4·It was found that the humus layer in black soil region was thick in north and thin in south, which was due to the climatic condition and soil-forming process.

研究发现，深厚黑土主要分布于黑土区北部，中厚与薄层黑土则分别集中在黑土区的中部和南部，这主要与黑土分布区的气候条件和黑土的成土过程有关。

5·This paper deals with the influence of a humus layer of different thicknesses on the water quality environment by measuring and analyzing the concentration of nitrogen nutritional salts.

通过对不同厚度淤泥水中氮营养盐的测定和分析，初步研究了不同厚度淤泥对水族箱水质环境中氮营养盐的影响。

6·The major factors of the soil developed from arenite were soil-layer depth, non-capillary porosity and humus depth.

砂岩发育的土壤主导因子是土层厚度、非毛管孔隙度和腐殖质层厚度。