桂西南不同地层土壤的元素地球化学特征

The Geochemical Characteristics of Soil Elements of Strata in Southwestern Guangxi

关键词:  地层  土壤  元素  地球化学

Key words:  stratum  soil  element  geochemical

摘要:

以隆安县为桂西南代表,根据地层、地形、土类等确定调查路线和采样点,挖掘土壤剖面,采集B层土壤,同一地层采集多个样品充分混合,以风干土混合样进行分析。测定21个地层土壤的Fe、Al、Si、N、P、K、Na、Ca、Mg、Mn、Zn、Cu、S、B、Mo、Co、Ni、Cr、Sr、Ba、V、As、Ge、Ga、Se、Cl、I、W、F、Br、Sn元素含量。其中Fe、Al、Zn、Ni、V、As、Se含量和Si、P、K、Na、Ca、Mg、S、Ga含量分别高于和低于世界土壤元素背景值,Mn、Cu、B、Mo、Co、Cr含量处于背景值范围。As的含量高于我国土壤临界含量。Ca、Mn、S的变异系数>100%,N、P、K、Na、Mg、Zn、Mo、Ni、Cr、Sr、Ba、As、Ge、Se、Cl、I、W元素的变异系数为50%~100%,Fe、Al、Si、Cu、B、Co、V元素的变异较小。该区石灰岩、白云岩、硅质岩等基性岩发育的土壤比由粉砂岩、页岩、泥岩和第四纪红土等基岩发育的土壤富铝化程度深,Fe、Al富集明显。各地层Si、Ca、Mg、Na、K的迁移量大,以Si迁移和Fe富集为主要特征。378对元素组合中,109对元素组合之间相关关系P<0.05,134对元素组合之间相关关系P<0.01,且以正相关为主;Si与其他元素间的关系多为负相关;过渡元素间大多有相关关系。该区主要植物的元素生物吸收顺序与地带性植被相似。

Abstract:

The Long' an area was chose as representative of the southwest of Guangxi. Survey route and sampling spots and soil profiles were determined according to strata, landform and type of soils. Soil samples were collected from several points in Layer B in the profile, and mixed and dried naturally for mensuration. The contents of elements Fe、Al、Si、N、P、K、Na、Ca、Mg、Mn、Zn、Cu、S、B、Mo、Co、Ni、Cr、Sr、Ba、V、As、Ge、Ga、Se、Cl、I、W、F、Br、Sn from 21 strata were determined. The contents of Fe、Al、Zn、Ni、V、As、Se are higher than the background values of soil elements of the world, and Si、P、K、Na、Ca、Mg、S、Ga are lower, and Mn、Cu、B、Mo、Co、Cr are in the range. The As content is higher than critical content of soils of China. The coefficient of variation of Ca, Mn,S were >100%;N、P、K、Na、Mg、Zn、Mo、Ni、Cr、Sr、Ba、As、Ge、Se、Cl、I、W are 50% to 100%,and Fe、Al、Si、Cu、B、Co、V are much smaller. Al and Fe have heavier enrichment in the soils derived from limestone, dolomites, silicolites than the soils from aleuvite, shale, pelite and Quaternary red soil. Si,Ca, Mg, Na and K in strata have great movement, with characteristic of Si movement and Fe enrichment. In the correlation of 378 element combinations, 109 element combinations are significant at P<0.05, 134 element combinations at P<0.01,and most of them are plus. Si has minus correlation with most of other elements. There are correlation among transition elements, and between Si and K, and between Ca and Mg. The correlation among S, N and P, and between Cl and Na are significant. The biological absorption order of main plants in this area is similar to that of zonal vegetation type.