珠江三角洲沉积物水稻土中管状结核特征研究  

Characterization of Tubular Nodules in Paddy Soil Derived from Deposits in Pearl River Delta

作　　者：贾重建 黄伟濠 卢瑛[1] 秦海龙[1] 姜坤[1] JIA Chongjian;HUANG Weihao;LU Ying;QIN Hailong;JIANG Kun(College of Natural Resources and Environment,South China Agricultural University,Guangzhou 510642,China;Guangdong Eco-engineering Polytechnic,Guangzhou 510520,China)

机构地区：[1]华南农业大学资源环境学院,广东广州510642 [2]广东生态工程职业学院,广东广州510520

出　　处：《生态环境学报》2019年第4期761-768,共8页Ecology and Environmental Sciences

基　　金：国家自然科学基金面上项目(41271233);国家科技基础性工作专项项目(2008FY110600;2014FY110200)

摘　　要：珠江三角洲沉积物水稻土形成发育过程中由于铁锰的迁移转化而在土体中形成了管状结核,了解结核的形貌和地球化学特征,有助于揭示成土环境条件变化和土壤发生演变规律。采集珠江三角洲沉积物水稻土不同发生层次土壤及管状结核,采用电镜扫描(SEM)、能谱分析(EDS)及化学分析方法研究了不同大小组分(以横切面直径筛分为<2 mm、2-4 mm、4-6mm、>6mm)的管状结核形貌特征、元素组成和分布特征。结果表明:研究区域管状结核表面颜色为亮黄棕色或黄棕色;结核横切面上总体形貌比较均一,未见环带状构造,且内部发现有硅藻残体存在;>6 mm与2-4 mm的结核横切面上元素分布规律相似,Fe的相对质量分数平均值(27.8%和42.3%)均远高于Si(14.4%和7.5%)、Al(8.0%和6.6%),且结核内边沿Fe相对质量分数高于外部;剖面Br2层和Bg层中结核均以Fe质量分数最高,其平均值分别为250.3 g·kg^(-1)、270.0g·kg^(-1),其次为Si(151.6 g·kg^(-1)、143.3 g·kg^(-1))和Al(69.7 g·kg^(-1)、62.7 g·kg^(-1)),而Mn质量分数仅分别为0.15 g·kg^(-1)和0.16g·kg^(-1);与土壤基质相比,Fe、P、Ni、Co、V和Pb等在结核中富集,铁的富集程度最大,而Mn未富集,因此该管状结核为铁质结核。Tubular nodules,are the products of evolution of paddy soil derived from deposits in Pearl River Delta due to the transformation and translocation of iron and manganese.Understanding the morphology and geochemical characteristics of tubular nodules is helpful to reveal the variation of forming condition and soil development.Samples of tubular nodules and soil matrices were collected from genetic horizons of the soils derived from deposits in Pearl River Delta,surface morphology,elemental composition and distribution characteristics of tubular nodules with different size(<2 mm,2-4 mm,4-6 mm and>6 mm by cross-section diameter)were analyzed by using electron microscopy(SEM),energy spectrum analysis(EDS)and chemistry analysis.Results showed that the colors of tubular nodules were bright yellow-brown or yellow-brown;the surface morphology structure of the nodules was homogeneous fabric,and diatom residues were found.Similar pattern of elemental distribution was detected in the cross-section of>6 mm and 2?4 mm nodules.The mass fractions of Fe(27.8%,42.3%)were higher than Si(14.4%,7.5%)and Al(8.0%,6.6%),and the relative mass fraction of Fe in the inner was higher than the edge of nodules.Fe mass fractionn were highest(250.3 g·kg^-1,270.0 g·kg^-1),followed by Si(151.6 g·kg^-1,143.3 g·kg^-1),Al(69.7 g·kg^-1,62.7 g·kg^-1)in nodules from Br2 and Bg horizon respectively,while Mn mass fractions were only 0.15 g·kg^-1 and 0.16 g·kg^-1,respectively.Compared with the soil matrices,Fe,P,Ni,Co,V and Pb was enriched in nodules,and the enrichment factor of Fe was the highest,whereas,Mn was not enriched.Therefore,the tubular nodules in the studied paddy soil are iron nodules.

关 键 词：管状结核 电镜扫描 能谱分析 元素组成 三角洲沉积物 珠江三角洲 

分 类 号：S151.1[农业科学—土壤学]