Soil Survey and Databases in Iceland lafur Arnalds Agricultural Research Institute, Keldnaholt, 112 Reykjavik, ICELAND Introduction Icelandic agriculture is characterized by the use of extensive rangelands for grazing and the making of hay for winter feeding. Cultivated land is of limited extent. Iceland has therefore traditionally put more emphasis on mapping vegetation resources rather than the soils. The history of soil science in Iceland is relatively young. Geologic aspects of the soils received considerable attention early on with the study of volcanic ash layers, but dating of soils by volcanic ash layers was pioneered by the Icelandic geologist Sigurdur Thorarinsson (19
  61). The first comprehensive map of of Icelandic soils was printed in 1959 at a scale of 1:750,000 (Nygard and Johanesson 19
  59). Other soil survey efforts were localized and this map together with Johannessons monograph on Icelandic soils (19
  60) remained the only complete survey of Icelandic soils until this year. In response to request made by the European Soil Bureau and other international agencies, the Agricultural Research Institute is now completing a soil map in the scale of 1:500,0
  00. Soil Mapping in the Past The pioneer work by Johannesson (19
  60) established a framework for the classification of Icelandic soils that is still valid. The soil map that was included in his monograph is attributed to Ivar Nygard who started this work in 1951, but after Nygard's death, Johannesson completed the map in co-operation with the US Soil Conservation Service. The map was printed by the U.S. Geologic Survey in 1959, but was included with both the Icelandic and English versions of Johannesson's monograph on Icelandic soils (19
  60). The monograph was reprinted in Icelandic by the Agricultural Research Institute in 19
  88. The underlying basis for Johannessons and Nygards work was the US soil classification system (Baldwin et al., 19
  38). Johannesson established a classification system based on 23 mapping units, but the soils were devided into three major groups, the freely drained soils (silt loams), poorly drained soils (peat soils) and the soils of the deserts (stony alluvial, aeolian, lag gravel, etc). At the time of Johanessons studies, the unique properties of Andosols were only beginning to be realized, which limits the present applicability of this work. It is noteworthy, however, that Johannesson wrote in his monograph: "…is the fact that many silt loam soils have some characteristics like those of the volcanic ash soils in other countries, for instance those of Japan, and thus perhaps might be considered as close relatives to or even as members of the so-called Ando soil group.." After the work of Johannesson, emphasis was mainly on agronomic aspects of Icelandic soils, such as fertilization of hay fields and draining of wetland soils.
Noteworthy is Helgason's comprehensive account of soils of South-west Iceland (1963; 19
  68). Two Ph.D. dissertations added considerable knowledge on the basic characteristics of Icelandic soils in the eighties by lafsson (19
  74) and Gumundsson (19
  78). The Agricultural Research Institute is still involved in soil evaluation for fertilizer recommendations, and has carried out extensive research related to soil fertility. The results have been reported both in specialized reports and as scientific papers (e.g., Palmason et al., 1996; Palmason and Helgason, 19
  96). Several attempts have been made to map soils in localized areas (e.g. Helgason and Gudbergsson, 1977; Gudbergsson and Olafsson, 19
  78), drawing much from the basis Johannesson provided. Gudbergsson (19
  82) made an outline for the classification of wetland soils (Histosols). Current Soil Mapping Activities Soil Taxonomy and FAO World Reference Base Soil mapping needs to be based on a suitable soil classification system. The Agricultural Research Institute collaborated with Texas A&M University and the USDA-NRCS to provide a new perspective on Icelandic soils for this purpose, with detailed analyses of several representative soil pedons (Arnalds, 1990; Arnalds et al., 1995; Arnalds and Kimble, unpublished data; Wada et al., 19
  92). These studies show that Icelandic soils are Andosols and Andic integrates of other soil groups to a large extent. More recent overview of Icelandic soils was published by Arnalds (1999a). The soils of the barren areas in Iceland are quite different from the typical Andosols and Histosol that cover other parts of the country. Arnalds (1988; 19
  90) and Gudmundsson (19
  91) have published studies on these soils. Arnalds and Kimble conducted a detailed analysis of ten representative pedons of Icelandic desert soils but the results are still being analyzed. A steady input of eolian materials and occasional tephra additions cause the organic carbon content to be lower than 25% in many of the wetland soils, resulting in Andisol (US-Soil Survey Staff, 19
  98) rather than Histosol classification (Arnalds et al., 19
  99). The desert soils are also often classified as Andisol because of their high volcanic glass content. The current edition of the US Soil Taxonomy (US Soil Survey Staff, 19
  98) has therefore the disadvantage in relation to the classification of Icelandic soils that it fails to distinguish between some of the major soil types at the highest level because of dominating andic influences. This can also be judged as a benefit, demonstrating the dominating influence of andic soil properties of Icelandic soils. Applying the FAO soil classification (FAO, 19
  98) system involves similar problems as for the US system in that many contrasting soils are classified the same at the highest level as Andosols. The wetland soils often do not meet the cryterion for Histosols because of relatively low organic content and the dominance of volcanic glass in desert soils often excludes Arenosols, Fluvisols, Cambisols and Regosols as soil groups. However, Thorsteinn Gudmundsson (19
  94) found that the FAO legend
(FAO-UNESCO, 19
  88) provided a good framework for mapping soils in Iceland. He translated and adapted the FAO system for use in Iceland. The Icelandic adoption of the FAO scheme for the soil groups (Gudmundsson, 19
  94) does not fully correlate with the FAO World Reference Base (FAO 19
  98) for reasons stated above. Its use may therefore cause problems in relating Icelandic soil information at an international level although, with modifications, it is well suited for domestic use. Current soil mapping effort The Agricultural Research Institute is currently making an effort to produce a soil map in 1:500,0
  00. Soil classification issues have not been resolved yet. A preliminary version of this map is published with this paper (Figure
  1). The soil information underlying the map is drawn from published and unpublished literature on Icelandic soils, which currently is being compiled for a databank and an overview publication. Some general characteristics are presented in Table
  1. Soil analysis generally follows standard methods designed for Andosols such as described by Blakemore et al., 19
  87. Soil descriptions generally follow US methods (eg., USDA-NRCS 19
  98).
The geographic information is mainly drawn from three sources:
  1. Vegetation maps. Vegetation reflects soil conditions, especially the distinction between wetlands (organic soils), freely drained vegetated Andosols and the deserts.
  2. Soil Erosion digital databases (see later in the paper). This information gives a good geomorphological overview of the desert surfaces, and is the primary source for their geographic information.
  3. Infrared satellite images (LANDSAT TM). They are used where there is a lack of
vegetation information. The images also provide the base map, correlated with Icelands current map projection system. The map was constructed using Arc/Info GIS software. The soil classes used in the map are as follows (note the class names are only suggestive at this stage and are subject to further development):
  1. Brown Andosols. These represent the typical Andosols of Iceland. They are usually freely drained and have developed in eolian and tephra materials that typically form a 80-200 cm mantle that has accumulated over an older surface (usually glacial till or lava). They are rich in allophane clay minerals, and ferrihydrate, but volcanic glass is also in abundance near the most active volanoes.Distinctive volcanic ash layers are common.
  2. Organic Andosols. These soils are found at poorly drained sites (bogs and myres), and often grade into Histosols. They most likely classify as Histosols in areas furthest away from eolian sources. The Organic Andosols are typically 50-500 cm thick with 5-30% C content. Volcanic ash layers are common.
  3. Vitric Andosols (or Gravelly Andosols).These soils are desert soils poor in organic matter compared to the classes above. They meet the criterion for Andosols (and Andisols) because of abundance of volcanic glass materials and other andic characteristics. The Vitric Andosols grade into Regosols (away from eolian tephra sources) and Leptosols.
  4. Leptosols. These soils are found on scree slopes, recent lava surfaces, and on lava surfaces where erosion processes have removed Brown or Organic Andosols from the top.
  5. Sandy Andosols. Sandy surfaces are common in Iceland near glacial margins and on glaciofluvial floodplains. Eolian processes have often carried sandy materials long distances from their sources, increasing the size of sandy areas. The sand is largely composed of volcanic glass.
  6. Leptosol/Sandy Andosol complex. This is a special class as this combination is very common in Iceland. It occurs where there is an abundance of sand on lava surfaces (due to eolian processes and volcanic ash fall). The sand covers the depressions while bedrock (lava surface) sticks out where the surface rises. Two other soil classes can readily be applied into this system, but can not be included on a map at such a coarse scale. These are Gleysols and Fluvic Andosols (which grade into Fluvisols, Gleysols and Regosols). Andosols in Iceland cover all together about 80,000 km2 and therefore make up a substantial proportion of the Andosols in the world. The areal extent of Brown Andosols represents an overestimate for two reasons. One is that desert areas /patches are common within areas dominated by the Brown Andosols. The second is that the land classification system used includes some areas within this class where the soils are too shallow to meet the criteria for Andisol/Andosol. At this point, it is not possible to account for this error. The three desert soil classes dominate about 38,000 km2, (actual extent is somewhat larger for the reason given above). They have vast potential for carbon sequestration
associated with ecosystem restoration (Arnalds et al. 19
  99). No data is available for the Leptosols yet. National Soil Erosion Database Soil erosion and degradation has been a major problem in Iceland since the arrival of man about 1100 years ago. The extent and severity of soil erosion in Iceland has been mapped at a scale of 1:100,000, by the Agricultural Research Institute and the Icelandic Soil Conservation Service. Erosion processes in Iceland are extremely varied and conventional methods designed for estimating erosion in cultivated areas are of little use. The erosion assessment is based on classification of erosion forms that can be identified in the landscape (Arnalds et al., 19
  97). The ARI-SCS erosion database is made of about 18,000 polygons. Each polygon is characterized by one or more erosion forms. Erosion severity for each of the erosion forms was estimated on a scale from zero to five, five being considered extremely severe erosion (Table
  2).
The overall results indicate the severity of erosion in Iceland, the scale of which is comparable only to very degraded, arid areas of the world. The combined total of considerable to very severe erosion is >50% of the country when high mountains and glaciers have been excluded. Much of this severe erosion occurs within the deserts, but severe erosion is also degrading large tracts of the remaining vegetated areas (see Arnalds et al., 1997; Arnalds, 1999b). Soil erosion continues to be monitored and mapped by the Icelandic SCS, in areas where it is most severe, but now at a larger scale (1:5,000 to 1:25,0
  00). Vegetation Mapping Although detailed soil maps have not been made for Iceland, much effort has been made to make vegetation maps. It was concluded around 1960 that vegetation maps would give more information about Icelandic nature than would soil maps, bearing in mind the major use of the land for grazing. It was expected that each of the vegetation mapping elements reveal information on the underlying soils. Mapping of the vegetation was conducted by the Agricultural Research Institute but
the programme has recently been relocated at the Institute of Natural History. Vegetation mapping has been completed for about 2/3 of the country at a scale of 1:40,000 in the highlands and 1:25,000 in lowland areas. Icelandic vegetation was split up into five major categories where drainage is the most influential factor. These categories are divided into 14 associations and about 100 mapping elements. Deserts are mapped separately. The methods were described in detail in a special issue of the Journal of Agricultural Research in Iceland (Thorsteinsson, 19
  82). Much of this data has been digitized and the Institute of Natural History has rece
 

相关内容

英语论文

   陆 丰 市 大 安 镇 石 寨 学 校 { 2010→2011 学年度第一学期 } → { Go For It } 八年级英语教学论文 八年级英语教学论文 英语 科任:薛美祝 科任 薛美祝 2011 年 01 月 14 日 1 初中英语书面表达失误的原因与教学策略 陆丰市大安镇石寨学校 薛美祝 书面表达是中学生学习英语应掌握的一项基本技能, 是初中英语 教学的重要内容和任务之一。它要求学生有扎实的语言基本功,具备 一定的审题能力、想象能力、表达能力和评价能力等。《英语课程标 准》也对学生的写 ...

英语论文

   初中英语教学论文:浅谈初中英语教学中的素质教育 「摘 要」基础教育阶段英语教学应以素质教育和学生发展为宗旨,通过优化课堂教学目标,改进教学方法、创设交际情境,提高教师素质等途径,使学生形成有效的学习策略,激发和培养学习兴趣,养成良好的学习习惯,注重对学生听、说、读、写综合技能的全面训练,获得基本的语言交际能力,为学生的发展和终身学习打下良好的基础。 「关键词」素质教育;课堂教学目标;教学方法;交际情境;教师素质 在广大农村初中,尽管英语教学已受到普遍重视,教学质量也在不断提高,但由 ...

英语论文

   1 中文翻译 1.1 钢筋混凝土 素混凝土是由水泥、水、细骨料、粗骨料(碎石或;卵石) 、空气,通常还 有其他外加剂等经过凝固硬化而成。将可塑的混凝土拌合物注入到模板内,并将 其捣实,然后进行养护,以加速水泥与水的水化反应,最后获得硬化的混凝土。 其最终制成品具有较高的抗压强度和较低的抗拉强度。 其抗拉强度约为抗压强度 的十分之一。因此,截面的受拉区必须配置抗拉钢筋和抗剪钢筋以增加钢筋混凝 土构件中较弱的受拉区的强度。 由于钢筋混凝土截面在均质性上与标准的木材或钢的截面存在着差异,因 此,需 ...

英语论文-- ---

   - 郑州市第一中学 英语研究性学习论文 题目: 关于动物名词在中西方语言中 关于动物名词在中西方语言中 题目 的差异 姓名: 姓名: 章馨元 郭雨晴 刘星枫 所在年级 高一年级 所在班级 十五班 指导教师 魏荣 完成时间 2009 年 5 月 23 日 综合评定成绩: 综合评定成绩: 指导教师评语: 指导教师评语: 评定成绩: 评定成绩: 指导教师签名: 指导教师签名: 教师签名 答辩小组意见: 答辩小组意见: 日期: 日期: 评定成绩: 评定成绩: 答辩小组长签名: 答辩小组长签名: 日期 ...

英语论文

   英语教学中如何进行问答 英语教学中如何进行问答 如何进行 摘要:英语课堂提问是教师授课过程中普遍采用的一种方式手段,它往往贯穿于教学全过程。既 是教师发挥主导作用、引导学生理解运用知识的重要途径,也是体现学生自主学习、成为课堂学 习主体的主要形式。在英语课堂教学中,课堂设疑提问的质量直接影响着教学的质量,影响着学 生思维的训练:本文结合自身的教学实践,尝试探讨课堂提问的基本原则。 关键词:英语课堂提问 适时性 启发性 准确性 正确性 英语教学中的问答不仅是加强英语基础知识教学, 培养学生英语 ...

英语论文

   整个高中教学都是为高考服务的 一、 语篇教学的必要性和紧迫性。 1:语篇阅读教学的模式就是以段落或篇章为教学的基本单位,以培养学生的语言运用能力 为目的,进行听、说、读、写、译等方面的训练的教学模式。 2:根据国家考试中心制定的《高考英语学科考试说明书》及《高考试题分析》的规定,最 近几年高考命题所依据的理论是:作为语言,各部分相加的总和不等于整体。也就是说,学 生虽然掌握了英语语法知识,掌握了英语词汇知识,并不等于学生学好了英语,并不意味着 学生的英语水平就很高。所以不能片面的强调语法,片 ...

英语论文

   齐齐哈尔大学 成人本科毕业论文(设计) 题目: 题目:The Comparasion of the Legend of Stone and Pride Prejudice 院 (系 ) 专 年 姓 业 级 名 齐齐哈尔大学继续教育学院 英语 09 级 孙晓东 学号 职称 指导教师 2011 年 1 月 15 日 齐齐哈尔大学 齐齐哈尔大学继续教育学院 毕业设计(论文) 毕业设计(论文)任务书 学生姓名: 孙晓东 学 院:齐齐哈尔大学继续教育学院 年 月 日至 学号: 班级: 年 月 日 任务 ...

英语论文

   AN ANALYSIS OF LANGUAGE FEATURES IN ENGLISH ADVERTISEMENTS 摘要 本文旨在通过对书面英语广告的语言分析总结出广告英语在词汇句法篇章上的语言特点。为了使研究从数据出发得出科学结论,本文作者建立了一个拥有60篇各类广告的小型语料库。通过对此语料库中日用品广告科技设备广告服务业广告的深入细致的定量和定性分析,总结出广告英语在此三类广告中的相同点与不同点,并且根据语言的意义,风格及功能解释广告英语的共性以及广告英语在不同类型广告中的特殊性。 本 ...

英语论文

   小学英语“情趣教学” 小学英语“情趣教学”漫谈 教育心理学告诉我们: 小学生的年龄特点是好奇心强、 模仿性强、 生性好动, 有意注意持续时间相对较短 。语言学习本身是较为单调枯燥的,而一味以教师 讲、学生听这种教学形式,势必使学生学习兴趣荡然无存。 只要学生感兴趣的 东西,他们就有求知欲,没有兴趣就不会有求知欲,学习热情大减,从而直接影 ,可以让学生在形式多变的教学 响学习效果 。因此,小学英语进行“情趣教学” 中,始终处于兴奋、活跃的状态,这样, 对教学是不无裨益的。那么,该如何 开展“情 ...

英语论文

   英文摘要模板(使摘要置于一页中) ABSTRACT(Times New Roman 三号加粗居中。行距 1.25 倍。 ) TXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXX……(正文为 Times New Roman 四号,1.25 倍行距) Key words: XXXXXX; XXXXXX (摘要正文下空一行顶格打印 “Key words ” “, Key words “之间以分号间隔, 内容为四号 Times New Roman,1.25 倍 ...

热门内容

新目标英语七年级下册unit1-4测试卷

   新元中学第一次月考英语试卷 新元中学第一次月考英语试卷 听力部分(共 25 分) I.听句子,选择与句子内容相符的图片。 分) (5 1. 2. 3. 4. 5. II 听句子,选择恰当的答语。 分) (5 ( )6 .A.She is from France. B.She speaks Franch. C.She is from Paris. , ( )7.A.Yes, he is . B.Yes, he does. C. No,he can t. ( )8.A.It is next to ...

2011年广东省高考英语新题型之仿真模拟考试试题(三)

   591up 有效学习(http://edu.591up.com ) 绝密★启用前 2011 年广东省高考新题型之仿真模拟考试试题(三) 年广东省高考新题型之仿真模拟考试试题( 仿真模拟考试试题 英 语言知识及应用(共两节, Ⅰ 语言知识及应用(共两节,满分 45 分) 语 本试卷共三大题,满分 135 分;考试用时 120 分钟。 完形填空(共 小题; 第一节 完形填空 共 15 小题;每小题 2 分.满分 30 分) 阅读下面短文,掌握其大意.然后从 1?15 各题所给的 A、B、C 和 ...

初一英语期中考试

   - 2002学年度 初一英语 2001第二学期 期中考试试卷 初一班,姓名, 成绩 Part A 一. 单词辨音 (5%) A 找出划线部分发音与其余三个不同的那个单词 1. A. bear B. hear C. near 2. A. talk B. always C. walk B. spring C. fifth 3. A. film B. cow C. brown 4. A. slow 5. A. certainly B. farmer C. her B 辨别下列各组单词划线部分的读音 ...

2011届高考英语各地模拟题分类汇编测试题7名词

   3eud 教育网 http://www.3edu.net 百万教学资源,完全免费,无须注册,天天更新! 高考各地模拟题分类汇编: 备战 2011 高考各地模拟题分类汇编:名词 () [2010?河南示范性高中五校 4 月联考]Most female workers in Beijing suffer from 1. connected to the global financial crisis, according to a recent survey. A. curiosity B. e ...

我的英语六级考试过级经验

   有一点我要告诉大家,考试只是一种手段,不是根本目的,证明不了什么。没通过下次再来就行!我只是一名普通高校的学生,现在不想再做菜鸟的我有了更新更远的目标,正在备战GRE考试,相信我CET的宝贵经历会助我一臂之力!我不想再做菜鸟,愿为展翅欲飞的大鹏! 我英语高考成绩仅只有可怜的90多分。对于我这种名副其实的菜鸟级人物,CET-6(没考四级)就是一种奢侈的梦。然而现实中I made it!在去年6月的考试中,我以社会考生的身份(学校不让报考,只好另寻他路)啃下了CET-6这块硬骨头。现在回 ...