不同植被恢复模式下中亚热带黄壤坡地土壤微量元素效应

Soil microelements under different vegetation restoration patterns in yellow soil slope region of mid-subtropics.

以武陵山区女儿寨小流域为例，研究了中亚热带黄壤坡地7种典型植被恢复模式下土壤微量元素有效性及其与土壤有机质、pH值之间的关系．结果表明：0～20cm土层荒草灌丛的B、Mn含量、油桐人工林Mo、Cu含量、杜仲人工林Zn含量和毛竹-杉木混交林Fe含量最高；20-40cm土层润楠次生林B、Fe、Mn含量、荒草灌丛模式Mo含量、油桐人工林Zn含量和杜仲人工林Cu含量最高；毛竹-杉木混交林B、Mo、Cu、Mn含量在各层土壤均最低．各元素有效性指数以Mn最高，Cu最低，排序为Mn〉Zn〉Fe〉Mo〉B〉Cu；土壤微量元素有效性综合指数以荒草灌丛模式最高（12．28），毛竹-杉木混交林最低（2．95），排序为Ⅶ〉Ⅴ〉Ⅲ〉Ⅳ〉Ⅰ〉Ⅱ〉Ⅵ．土壤有机质含量与B、Zn有效态含量之间线性关系显著，二次多项式亦可较好地描述有机质与有效态Mn之间的关系，而有机质与Mo、Fe、Cu之间曲线回归关系不显著．土壤pH值与土壤Zn、Cu呈显著正相关，与Mn、Mo也有较好的相关性，而与B相关性较低，与Fe为弱负相关．

With the Niierzhai watershed in Wuling Mountain as a case, this paper studied the contents and availabilities of soil microelements and their relationships with soil organic matter and pH value in yellow soil slope region of mid-subtropics under seven typical vegetation restoration patterns, i. e. , Pinus massoniana natural forest （ Ⅰ ）, Cunninghamia lanceolata plantation （ Ⅱ ）, Eucommia ulmoides plantation （ Ⅲ ）, Vernicia fordii plantation （ Ⅳ ）, Machilus pingii secondary forest （ Ⅴ ）, Phyllostachys edulis - C. lanceolata mixed forest （ Ⅵ）, and wasteland-shrub community （Ⅶ）. It was found that in 0-20 cm soil layer, the contents of B and Mn, Mo and Cu, Zn, and Fe reached the peaks under Ⅶ, Ⅳ, Ⅲ and Ⅵ ; while in 20-40 cm soil layer,Ⅲ, Ⅳ, Ⅴ and Ⅶ had the highest contents of Cu, Zn, B, and Fe and Mn, Mo, respectively. In both two soil layers under Ⅵ, the contents of B, Mo, Cu and Mn were the lowest. Mn had the biggest single element available index, while Cu had the smallest one. The biggest and smallest total available index of soil microelements was 12. 28 for Ⅶ and 2. 95 for Ⅵ, respectively. There existed the regularities of Mn 〉 Zn 〉 Fe 〉 Mo 〉 B 〉 Cu for single microelement available index and Ⅶ 〉 Ⅴ 〉Ⅲ 〉 Ⅳ 〉 Ⅰ 〉 Ⅱ 〉 Ⅵ for comprehensive microelement available index under different vegetation patterns. A good linear relationship was observed between soil organic matter and B and Zn availabilities, and the relationship of soil organic matter with available Mn could be described by a quadratic equation. Soil pH was highly positively correlated with soil Cu and Zn contents, correlated with soil Mo and Mn contents, slightly correlated with soil B content, and slightly negatively correlated with soil Fe content.