阿拉善荒漠灌木根际中、微量元素含量特征

The characteristics of medium and trace element concentrations in the rhizosphere of desert shrubs,Alxa

探讨了阿拉善干旱荒漠区霸王、白刺、红砂、沙冬青、沙木蓼、梭梭和驼绒藜7种旱生灌木根际与非根际土壤Ca、Mg、Fe、Mn、Zn、Cu的含量特征。结果表明:(1)除梭梭根际pH值高于非根际之外,其余6种灌木根际土壤均表现出不同程度的酸化作用。(2)7种灌木根际全钙和交换性钙的含量均低于非根际。除沙木蓼和驼绒藜外,其余5种灌木根际全镁含量均高于非根际,白刺的富集率最高,为43.04%;除沙木蓼外,其余灌木根际交换性镁的含量均有所富集,梭梭的富集率最高,为26.52%。(3)7种灌木根际全铁、全锰、全锌含量总体上小于非根际,但是根际有效铁、有效锰、有效锌含量均大于非根际,表现出明显的富集效应,沙木蓼根际有效铁、有效锰、有效锌的富集率最高,分别为:29.76%、20.92%、86.99%。(4)沙木蓼根际全铜和有效铜含量略高于非根际。梭梭根际全铜含量低于非根际,但梭梭根际有效铜含量却有富集的趋势。其余五种灌木根际全铜和有效铜含量均低于非根际。(5)根际及非根际土壤各养分性状之间,存在复杂的相关性。

The characteristics of Ca, Mg, Fe, Mn, Zn and Cu concentrations in the rhizosphere and the rhizospheresurrounded bulk soil of the 7 desert shrubs （i. e. Zygophyllum xanthoxylum, Nitraria tangutorum, Reaumuria soongorica, Ammopiptanthus mongolicu, Atraphaxia bracteata, Haloxylon ammodendron, Ceratoides lateens） in Alxa were investigated. The results revealed as follows. （ 1 ） Although pH value in the Haloxylon ammodendron rhizosphere was higher than that of the bulk soil, the other six shrubs showed varying degrees of acidification in the rhizosphere soil. （2） Contents of the total Ca and exchangeable Ca in the rhizosphere of all the seven shrubs were lower than those of the bulk soils. The total Mg content was higher in the rhizosphere than in the bulk soil for all shrubs except Atraphaxia bracteata and Ceratoides lateens, and the highest enrichment rate occurred in Nitraria tangutorum （43.1% ）. The exchangeable Mg content was significantly accumulated in the rhizosphere except for Atraphaxia bracteata, with Haloxylon ammodendron having the highest enrichment rate of 26.5%. （3） Overall, the contents of total Fe,Mn and Zn in the rhizosphere were lower than those of the bulk soil, but there was a significant rhizosphere effect on the contents of available Fe, Mn and Zn whose enrichment rates in the rhizosphere of Atraphaxia bracteata were 29.8% ,20.9% and 86.9%, respectively. （4） Contents of the total Cu and available Cu in the Atraphaxia bracteata rhizosphere were slightly higher than in the bulk soil. The content of total Cu in the Haloxylon ammodendron rhizosphere decreased, but the content of available Cu in its rhizosphere increased. Contents of the total Cu and available Cu in the rhizosphere for the other shrubs were lower than those in the bulk soil. （5）There was a complicated correlation between soil nutrients in the rhizosphere and the bulk soil.