腐殖质

Our focus in composting is to create humus.

我们的重点在堆肥是为了创造腐殖质。

Our focus in composting is to create humus.

我们的重点是在制造堆肥腐殖质。

Conventionally the layers have been divided into A, B and C horizons. The A horizon is the upper layer, containing humus and is leached and,or eluviated of many minerals. The B horizon forms a zone of deposition and is enriched with clay minerals and iron,aluminium oxides from the A layer. The C layer is the parent material for the present soil and may be partially weathered rock, transported glacial or alluvial material or an earlier soil.

传统上可将土壤分成A、B、C三层。A层是位於最上面的一层，含有腐殖质，许多矿物质在该层中沥滤和淋溶。B层是个沉积区，富集了大量的来自A层的粘土矿物质和铁，铝氧化物。C层是现在土壤的母质层，也可能是风化的岩石、来自冰河或冲积层的物质、或早期土壤遗留下来的。

The results show that 42.86% topsoil samples are polluted by Cadmium, soil synthesis pollution index is moderate, Cadmium pollution degree of topsoil correlate with the environment of sampling sites. The results also show that exchangeable Cd, carbonate-bound Cd, organic-bound Cd and residual Cd are found in all soil samples except for Fe-Mn oxide-bound Cd. Furthermore, the concentration of exchangeable Cd and carbonate-bound Cd, both which have high biological validity, is high. Humus has a certain correlation with exchangeable Cd, organic-bound Cd and residual Cd, and has no obvious correlation with other chemical speciations. Any chemical speciation of Cd has no obvious correlation with pH and total Fe of soil samples. Cadmium in topsoil can be eluviated by acid solution, the quantity of Cadmium eluviated by redistilled water is little. With the rise of pH of eluviating solution, eluviated Cadmium quantity decrease. For the same soil sample, the lower pH value of eluviating solution is, the more fast the Cadmium is eluviated, and the more thequantity of Cadmium is eluviated.

研究结果表明：成都市表生土壤样中有42.86%受镉污染，镉综合污染水平达中度污染，成都市表生土壤镉污染程度与采样点周围环境表现出一定的相关性；除铁锰氧化物结合态镉在部分土壤样中未检出外，所有土壤样均含有可交换态镉、碳酸盐结合态镉、有机结合态镉、残留态镉，且生物有效性较高的可交换态镉和碳酸盐结合态镉占总镉量比例较高；成都市表生土壤中的腐殖质与可交换态镉、有机结合态镉、残留态镉有一定相关性，与碳酸盐结合态镉、铁锰氧化物结合态镉相关性不显著；各形态镉与土壤pH值和全铁的相关性均不显著；土壤中的镉可被酸溶液淋出，重蒸馏水淋出镉量十分微小；随着淋滤液pH值的升高，土壤样的镉淋出量下降，且0～5小时时段的镉淋出量占镉总淋出量比例下降，5～30小时时段的镉淋出量占镉总淋出量的比例上升，对同一土壤样而言，酸度大的淋滤液比酸度小的淋滤液淋出镉速度更快，淋出镉量更大。

They may need addition of humus or mulches to improve water and mineral retention and prevent leaching.

要提高此种土壤的保水保矿物分子能力并防止矿物被滤去需要加入腐殖质或地面覆盖物。

Wind and spring floods erode soils , exposing underlying layers and premiering new compositions of humus and minerals on the surface .

风和开春季洪水侵蚀着土壤，暴露出地下土层，新组成的腐殖质和矿物成分初露地表。

Wind and spring floods erode soils , exposing underlying layers and premiering new compositions of humus and minerals on the surface .

风沙和水灾侵蚀着土壤，暴露出地下土层，腐殖质新成分及其表面的矿物。

Wind and spring floods erode soils , exposing underlying layers and premiering new compositions of humus and minerals on the surface .

风和开春暴涨的溪水侵蚀着土壤，暴露出地下土层，腐殖质和矿物成分初露地表。

Black clay soil ; humus ; black humic acid ; optical density index

黑粘土；腐殖质；黑色胡敏酸；光密度指数

Keywords: Humic acid; Cultivated brown soil; Potassium release and fixation; K-bearing mineral

中文关键词：腐殖质；耕地棕壤；钾素释放与固定作用；含钾矿物

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。