南海诸岛土壤的地球化学特征及其生物有效性

南海诸岛主要由三类土壤组成，即富磷岩性均腐土，盐成土和新成土。这些土壤均发育于具有强石灰性的生物碎屑沉积物之上。富磷岩性均腐土的元素含量与母质相比，Ｐ、Ｚｎ、Ｃｕ、Ｂａ、Ｃｄ等元素含量较高，且随成土时间的增加，其含量有增加的趋势，而Ｍｇ、Ｃａ、Ｓｒ、Ｂ、Ｖ、Ｐｂ、Ｍｏ等元素含量较低，随成土时间的增加逐渐降低。新成土和盐成土除Ｐ和Ｎａ元素含量较高外，其余元素均接近母质。南海诸岛独特的生物气候、母质等     

Improved Elemental Recoveries in Soils with Heating Boric Acid Following Microwave Total Digestion

Abstract

Microwave digestion of soils for elemental analysis commonly uses hydrofluoric acid (HF) because of insolubility of aluminosilicate minerals in other acids. Boric acid is added following digestion to complex F in solution. Low recoveries of calcium (Ca), aluminum (Al), and magnesium (Mg) of soil reference materials led to this investigation of a secondary heating of the boric acid with digested soil. The objectives were to evaluate boric acid (H₃BO₃) concentrations needed to complex F from 4 mL HF and to evaluate soil characteristics that may contribute to the formation of metal‐fluoride complexes that decrease recovery following digestion. Four standard soil reference materials and a variety of soil samples (n=75) were evaluated. Heating 20 mL 2.5% H₃BO₃ with a digested standard reference soil produced recoveries of 94, 98, and 99% for Al, Ca, and Mg, respectively, compared to 46% for Al and Mg and 37% recovery for Ca in extracts where H₃BO₃ was added but not heated. Two other concentrations of H₃BO₃ were tested with slightly improved recoveries, and results suggest that 20 mL of a 4.5% H₃BO₃ solution was sufficient to maximize recoveries. Digestion of soil samples by both the nonheated and heated H₃BO₃ methods showed that recovery difference between the two methods ranged from 0 to 100% for Al and Ca. Assuming that this difference in recovery was related to the formation of metal fluorides, correlation with clay and C in soils may reflect the positive or negative influence of these constituents on the formation of these complexes, respectively.     

A landscape-geochemical approach in insular studies as exemplified by islets of the eastern Baltic Sea

The main objective of our investigations is to find out the primary geochemical properties of insular landscapes in order to ascertain the landscape stability on an area of land uplifting in the conditions of a regressive sea. Therefore we focus our study on the landscapes of Kolga Bay islets, which are located near the Estonian coast in the Gulf of Finland. A landscape-geochemical approach of landscape study improves the mapping of insular landscapes and understanding of processes of landscape development. Besides land use changes, land uplift and marine influence shape the landscape patterns of island through topography and subsurface water. We propose geochemical typology of landscapes based on substance movement (eluvial, superwatery, subwatery), field studies on islands, and chemical analysis of soil and water samples. From a landscape geochemical perspective, types of matter fluxes mainly control stability of an insular landscape. Interactions between geochemical, ecosystem and geomorphic processes reveal that islands behave as systems, rather than merely a sequence of interdependent soil-vegetation complexes along topographic gradients. This revised version was published online in August 2006 with corrections to the Cover Date.     

兰州白兰瓜产区的土壤地球化学环境特征

研究结果表明，兰州白兰瓜产区的土壤地球化学环境具有：1）有机质的含量低，积累速度慢；2）元素的横向迁移速度不显著，没有显著的规律，垂向迁移比较显著，而且，不同使用年限的砂田，元素迁移的速度不同，一般新砂田最快，中砂四元素淋虑速度显著降低，老砂田又有所回升；3）不同元素的正向迁移规律和速度，在不同使用年限的砂田上表现不同；4）富硅、富铝。     

宿州重污染河流氮磷污染多源识别及背景值

[目的]研究宿州市重污染河流奎河宿州段的污染源头和环境背景值。[方法]对河水进行总氮、总磷分析测试,并进行密度曲线图分析、频率直方图分析和Q聚类分析。利用正态法获取奎河总氮、总磷的环境背景值。[结果]奎河宿州段河水污染严重,受到人为因素污染程度大,污染源主要为工业废水、生活污水和农业污水。总氮环境背景值为0~6.66 mg/L,总磷环境背景值为0~0.84 mg/L。[结论]该研究可为奎河治理标准提供科学依据。     

章丘大葱品质与微量元素的关系

[目的]了解微量元素的生态效应,为农业的合理规划与科学发展提供地质依据。[方法]运用生态地球化学的研究思路,依据章丘地区局部生态地球化学调查的成果,分析了章丘大葱的物质成分,运用相关分析法研究了大葱主要成分同植物体及对应土壤中微量元素之间的相互关系。[结果]大葱的品质与植物体及土壤中的微量元素之间存在着一定的联系,但是其相关性整体而言不明显。[结论]微量元素对于大葱的生长具有较明显的影响。     

章丘大葱生产基地硒元素的生态地球化学研究

利用局部生态地球化学调查评价成果,对章丘地区大葱产地土壤中的硒进行了系统研究,分析了表层土壤及大葱中硒的生态地球化学特征,探讨了植物中硒含量与土壤硒含量的关系。研究表明,章丘地区土壤中硒含量充足,适宜发展特色富硒大葱。     

氢氧稳定同位素技术在土壤水研究上的应用进展

土壤水是水资源的重要组成部分,是连接自然界水循环的重要环节;一个地区的土壤水资源状况与当地作物生产、生态环境质量以及社会经济发展息息相关。应用稳定氢、氧同位素技术可从宏观和微观的结合上把握土壤水循环过程,阐明其相关机理;近年来这一技术有了长足进步,正在逐渐发展成为研究土壤水循环特别是探究土壤水分运移和转化规律的有效手段。在简述土壤水氢、氧同位素基本知识的基础上,从水的地球化学循环原理出发,讨论影响土壤水氢、氧同位素富集的因素,着重介绍了土壤水循环研究中的同位素技术的要点和特点,并对这一研究领域未来的发展进行了展望。