贵州省习水县表层土壤硒地球化学特征及影响因素分析

本文在贵州省习水县1∶50000耕地质量地球化学调查评价工作基础上,经过取样调查分析,查明了习水县境内耕地表层土壤的环境综合质量及硒的地球化学分布特征,初步探讨了影响表层土壤硒含量高低和分布的因素。结果表明,习水县耕地土壤总体呈中性—酸性,土壤环境综合质量较好。全县耕地表层土壤硒平均含量为0.44 mg/kg,富硒（0.4～3.0 mg/kg）占比55.53%,在全县均有分布。研究区的富硒土壤分布与成土母岩有较大的关系,二叠系龙潭长兴组含煤地层发育的土壤硒含量最高可达1.374 mg/kg,最低为上侏罗统蓬莱组发育的土壤,为0.285 mg/kg;不同的土壤类型,石灰土和黄壤的硒含量较高,分别为0.75 mg/kg、0.58 mg/kg,紫色土的含量相对较低,为0.31 mg/kg;不同的土地利用类型中,茶园的硒含量最高,为0.69 mg/kg,水田最低,为0.40 mg/kg;Pearson相关性分析结果表明,有机质含量与土壤硒呈正相关关系,pH与土壤硒无显著相关性。     

宁夏石嘴山地区土壤硒的来源及影响因素研究

宁夏石嘴山地区作为新发现富硒土地的地区,前人对该区土壤硒的来源及影响因素研究甚少。本文以石嘴山地区富硒土壤为研究对象,通过采集岩石、表层土壤、土壤剖面样品,研究Se元素在土壤中的分布特征、成因来源及影响因素。本文认为石炭系地层是Se元素的有利赋存层位,Se元素的含量为0.847~1.728 μg/g。砂岩、页岩中较发育的石英裂隙及石英的重结晶作用为硒晶体的共生和填充提供了场所。另外,通过表层土壤Se和垂向剖面土壤Se的含量分布特征,较全面地分析了土壤Se的影响因素,结果显示,表层土壤中Se元素的含量与Cd、Cr、Zn、Pb、TFe₂O₃、N和有机质呈明显的正相关,与pH呈负相关。土壤Se在垂向上主要受淋滤作用的影响,而生物积累作用的影响不大。本次研究成果对富硒土地资源的开发与利用具有一定的指导意义。     

大沽河流域蔬菜基地土壤氮素养分现状调查与分析

对大沽河流域蔬菜基地土壤氮素养分现状情况进行了调查研究,分析了露天土壤和设施土壤铵态氮、硝态氮、碱解氮、全氮等的垂直分布规律及原因.结果显示:该流域菜地土壤氮素累积现象比较严重,表层(0~20cm)土壤氮素累积现象尤为严重.两种农业生产模式下铵态氮、硝态氮含量无明显差别,而碱解氮、全氮的含量设施明显高于露天.除硝态氮外,其他氮素分布具有明显的层次性,含量一般随土壤深度增加而减少.表层(0~20cm)土壤铵态氮高于40~60cm土层含量数倍,平均含量在13mg/kg左右,最高达65.01mg/kg;硝态氮在0~60cm土层中均有较高累积量,平均含量在14~28mg/kg之间,最高达55.18mg/kg;露天和设施在0~40cm土层中的碱解氮、全氮含量几乎全部达到中等水平及以上.     

河南省睢县西南部土壤硒的地球化学特征及影响因素

本文以表层、深层土壤的地球化学调查数据为基础,结合数理统计方法,对河南省睢县西南部农用地的土壤地球化学特征以及硒元素的分布规律和影响因素进行了探讨。结果表明,研究区土壤硒平均含量为0.24 μg/g,其中Se>0.30 μg/g的土壤面积约1200 hm²,占研究区总面积的11.65%;表层土壤中非金属元素（N、P、S）和金属元素（Mo、Cd、Cu、Hg、Zn）的含量与硒含量相关性较高,对硒含量的影响较大;土壤硒含量受成土母质的影响,与有机质呈显著的正相关关系,但与土壤pH关系不显著;垂向上土壤Se元素含量自上而下基本呈现逐渐减小的趋势。研究成果可为当地政府今后富硒土地规划利用、富硒农业的发展等提供科学依据。     

贵州省湄潭县农用地表层土壤地球化学特征及成因分析

本文基于湄潭县农用地表层土壤地球化学数据,运用数据统计分析及因子分析等方法,获得研究区农用地表层土壤23种元素(指标)地球化学背景值、分布特征以及成因。研究区表层土壤整体偏酸性,常量营养元素呈富氮、缺钾的特点,硒元素含量较高,富硒土壤分布广泛,为区内发展富硒特色农业提供了基础保障。采用因子分析法提取了8个因子,可以反映研究区农用地表层土壤75.671%特征成因。影响其地球化学特征的主要因素有地质背景、成土母质、植物根系富集、矿产生产活动、人工施肥、大气降雨等因素。研究结果可以为当地农业发展、土地规划、配方施肥、土壤环境保护提供一定参考。     

陕西咸阳某地富硒土地资源的可开发性初探

富硒土壤的评价是富硒土壤资源开发利用的前提和基础,为评估富硒土壤的可开发性,在前期土地质量地球化学评价的基础上,采用指数法,以关中平原土壤富硒含量(硒含量≥0. 2 mg/kg)为参比值,进行土壤的富硒程度及富硒农产品的安全性评价。结果表明:土壤中硒含量以0. 30～0. 40 mg/kg为主,约99. 71%农用地块土壤硒含量符合可开发标准;土壤环境质量良好,清洁土壤约占农用地块总面积的98. 50%,具备了开发富硒产品的基本环境条件;小麦样本富硒率达82. 61%,重金属安全率达到95. 65%,玉米样本富硒率达85. 71%,重金属安全率达到100%,认为研究区具备开发利用富硒农产品的条件,可进行富硒土壤资源的开发。     

陕西关中地区土壤硒分布特征及影响因素

富硒土地的价值在于其能开发出天然富硒农产品,为当地农民增收、农业增效、精准扶贫做出积极贡献。文章系统总结了关中地区39 500 km~2范围内土壤硒的含量特征和影响因素。结果发现,研究区有富硒土地8245. 12 km~2,主要分布在渭河两岸。深层土壤以低硒为主要分布特征,占全区面积的88. 23%。表层土壤硒含量相对于深层土壤明显富集,继承成土母质(深层土壤)程度较弱,进一步研究显示,风沙土、潮土和水稻土的深、表层土壤硒存在弱相关,黄绵土、褐土、新积土等表层土壤硒的富集作用与深层土壤硒含量没有显著关联。土壤类型是影响关中地区土壤硒含量的主要因素,不同类型土壤中有机质对硒具有明显的富集作用,p H值对硒的约束存在显著差异。     

河北承德中部伊逊河红旗地区土壤生源要素空间分布格局及其影响因素

土壤生源要素的含量和空间分布特征对指导土壤肥力调控,优化土地利用具有重要意义。以承德市伊逊河红旗周边地区为例,采集不同深度和典型剖面土壤样品,综合运用描述性统计、地统计半方差函数模型和冗余分析等方法,论述了研究区土壤生源要素碳、氮、磷和钾的空间分布格局与影响因素。结果表明,研究区表层土壤TN含量平均为848.74 mg/kg,总体较为缺乏;土壤Corg平均含量为1.35%,总体属中度水平;TP和TK含量相对丰富。TN、Corg、TP和TK土地质量地球化学等级属较丰富以上水平的样品占比分别为7.71%、26.18%、35.08%和77.85%。深层土壤TN和TP含量显著低于表层土壤,垂向分布上TN和TP含量总体呈随深度增加而降低的趋势,TK含量呈先下降后上升的趋势。土壤TP和TK空间分异以结构性变异为主,具有强烈的空间自相关性;TN和Corg分布具有中度的自相关性,空间分布受土地利用类型控制,也受农业活动等人为因素影响;土壤TP空间分布受成土母质和矿业活动因素共同影响,土壤TK空间分布则主要受成土母质自然因素控制。     

安徽省潜山市富锌土壤资源分布特征及成因分析

本文利用安徽省潜山市土地质量地球化学调查评价数据资料,对潜山市富锌土壤资源的分布特征及成因进行了分析研究。结果表明:研究区土壤锌含量平均值为70.7 mg/kg,变化范围在18.7~2964.5 mg/kg,富锌土壤面积为365.90 km^(2),占研究区面积的21.71%。研究区土壤锌含量受土壤类型、土地利用方式的影响,与土壤有机质呈弱正相关关系;研究区土壤pH值整体呈酸性,土壤pH值对土壤锌含量影响不显著。通过对研究区成土母质、大气干湿沉降物与灌溉水中锌含量分析显示,土壤中锌主要来源于土壤母质,不受大气干湿沉降与灌溉水的影响。     

绿肥翻压还田对土壤理化性状的影响

通过种植绿肥翻压还田和不还田两种方式对土壤养分变化进行监测，结果表明：绿肥翻压还田与种植前相比，土壤全氮、全磷、有效磷、全钾、缓效钾、速效钾分别增加0.13g/kg、0.04g/kg、5.33mg/kg、0.98g/kg、17.2mg/kg、7.93mg/kg；与种植绿肥不翻压还田相比，土壤全氮、全磷、有效磷、全钾、缓效钾、速效钾分别增加0.24g/kg、0.05g/kg、2.80mg/kg、1.31g/kg、19.9mg/kg、8.71mg/kg。绿肥翻压还田后土壤有机质含量明显提高，土壤容重降低，pH值上升，改良土壤理化性状和提高肥力效果明显。     

Selenium in soil and endemic diseases in China

Selenium is an essential element for humans, animals and some species of microorganisms. The biological function of selenium shows dual characteristics. The selenium content range between toxic and deficient concentration is very narrow. The present paper discusses the geographical distribution of two forms (total and water-soluble) of selenium in topsoil (plough layer for cultivated soils, eluvial horizon for natural soils) and evaluates its relationship with some human health problems in China. Topsoil samples, 354 in total, including 156 natural and 198 cultivated soils of 21 main soil types were collected. The total Se concentration in soil samples was determined with DAN (di-aminonaphthalene)-fluorescence spectrophotometer method. Soil water-soluble Se concentration was determined with the same method after extraction with water (water/soil = 5:1). The results showed that the geometric and arithmetic means of total Se concentration in soil, for all samples, were 0.173 mg/kg and 0.239 mg/kg, respectively, with the lowest value being 0.022 mg/kg and the highest being 3.806 mg/kg. For the cultivated soil, the geometric mean of total Se was 0.188 mg/kg, its arithmetic mean was 0.269 mg/kg and higher than those in the natural soil, 0.154 mg/kg and 0.206 mg/kg, respectively. The geometric and arithmetic means of water-soluble Se in soil for all the samples were 4.0 and 6.4 microg/kg, the lowest 0.6 microg/kg and the highest value being 109.4 microg/kg. For the cultivated soils, the average concentration of water-soluble Se was 4.3 microg/kg, similar to that of natural soil, they are and 4.4 microg/kg by geometric mean. Two sequences of the soil types, arranged separately in the concentration of total Se and water-soluble Se, are different and this demonstrates that the proportions of the two forms of selenium existing in various soils are different. The percentages of water-soluble Se to total Se in different types of soils varied from 1.07 to 6.69%. However, generally the laterite and other subtropic soil still have relatively high absolute water-soluble Se contents because of their higher total Se contents. A very significant correlation between total Se and water-soluble Se has been found in cultivated soil with a correlation coefficient of 0.58 (P < 0.01). The relationships between soil Se and human endemic diseases Keshan disease, Kashin-Back diseases and selenosis have been discussed. The reference criteria for evaluating Se deficiency and Se excess in soil were suggested.     

河南商丘地区土壤有机碳密度及其空间分布特征

利用多目标地球化学调查数据,对商丘地区表层(0~20 cm)、中上层(0~100 cm)和全层(0~200 cm)土壤有机碳密度及其储量进行了估算,并分析不同土壤类型、地貌类型及土地利用类型下土壤有机碳密度的空间分布特征及影响因素。结果表明:研究区土壤碳库以无机碳为主,表层、中上层、全层有机碳密度分别为2.34 kg/m~2、2.82 kg/m~2、7.89 kg/m~2,均低于全国平均水平。在不同土壤类型、地貌类型及土地利用类型间有机碳密度存在显著差异,土壤有机碳含量及分布受气候及土壤理化性质影响不明显,温度是主要影响因子。     

The Use of Biosolids and Other Organic Substances in the Creation of Soil-Forming Materials

This paper describes an experiment which was carried out at a landfill site in north Lincolnshire to investigate the use of biosolids and other organic materials in soil formation. The following organic amendments were incorporated into the surface of the on-site geological clay to form 'topsoil'treatments: (i) nil, (ii) biosolids (digested cake), (iii) waste peat/compost, and (iv) composted green waste. The biosolids were applied at a rate of 70 tDS/ha and all the organic materials were incorporated to a depth of 150 mm. The organic amendments reduced the topsoil bulk density and increased plant available water supply and soil water infiltration rates. Topsoil organic matter, total nitrogen and extractable phosphorus concentrations, biomass nitrogen, readily mineralisable organic nitrogen and soil respiration rates were also increased. Additionally, the biosolids application increased topsoil aggregate stability and soil surface strength.     

多功能复合微生物菌剂对污泥堆制营养土的影响

为了研究外源微生物对营养土堆制过程的影响程度,选择多功能复合微生物菌剂(MCMP-Ⅱ)开展污泥堆制营养土的试验.试验结果表明:MCMP-Ⅱ的添加增加了总氮的损失,降低了碱解氮的转化效率,大幅度提高了有效磷含量及发芽指数增加率,但对总磷、钾含量的增加率提高较小.总氮、碱解氮与MCMP-Ⅱ、其他营养指标及发芽指数均呈负相关,其他各指标之间呈正相关;在0.05水平下菌剂与总氮呈显著负相关,发芽指数与总磷、有效磷呈显著正相关;而在0.01水平下,菌剂与碱解氮呈极显著负相关.MCMP-Ⅱ能够加快总氮中氮元素状态的转化,同时对磷元素转化的影响亦较大,其中存在反硝化及提高有效磷转化效率的菌种.MCMP-Ⅱ对污泥堆制营养土过程中营养物质及发芽指数的影响排序为碱解氮>总氮>发芽指数>总磷>有效磷>钾.     

Soil arsenic availability and the transfer of soil arsenic to crops in suburban areas in Fujian Province, southeast China

The bioavailability, soil-to-plant transfer and associated health risks of arsenic in soils collected from paddy rice fields and vegetable fields in suburban areas of some major cities of Fujian Province were investigated. The total soil concentrations of arsenic ranged from 1.29 to 25.28 mg kg(-)(1) with a mean of 6.09 mg kg(-)(1). Available (NaH(2)PO(4)-extractable) arsenic content accounted for 0.7-38.2% of total soil arsenic and was significantly correlated with total soil arsenic content. For the vegetable soils, the available fraction (ratio of available As to total As) of arsenic decreased with decreasing silt (particle size 0.02-0.002 mm) and free iron (DCB extractable) contents and with increasing soil pH and organic matter content. The available fraction of arsenic in the paddy rice soils increased with increasing free iron and organic matter contents and decreasing soil pH and silt content. The correlation of NaH(2)PO(4)-extractable arsenic with the arsenic concentration of the vegetables was much better than that of total As. The transfer factor based on the soil available arsenic (TF(avail)) was chosen to compare the accumulation ability of the various crops. The TF(avail) values of rice grains (air-dried weight basis) ranged between 0.068 and 0.44 and were higher than those of the vegetables, ranging from 0.001 to 0.12. The accumulation ability of the crops decreased in the order of rice>radish>water spinach>celery>onion>taro>leaf mustard>fragrant-flowered garlic>pakchoi>Chinese cabbage>lettuce>garlic>cowpea>cauliflower>bottle gourd>towel gourd>eggplant. Daily consumption of rice and other As-rich vegetables could result in an excessive intake of arsenic, based on the provisional tolerable intake for adults for arsenic recommended by WHO.     

Arsenic biogeochemistry and human health risk assessment in organo-arsenical pesticide-applied acidic and alkaline soils: an incubation study

Organo-arsenical compounds are considered non-carcinogenic, and hence, are still allowed by the regulatory agencies for use in agriculture as pesticides. Due to rapid encroachment of suburban areas into former agricultural lands, the potential for human exposure to soil-arsenic has increased tremendously in recent years. However, insufficient data is available on the stability of organo-arsenicals in soils; as to whether they remain in an organic form, or are converted over time to potentially carcinogenic inorganic forms. A static incubation study was conducted to estimate soil speciation and in-vitro bioavailability (i.e., bioaccessibility) of arsenic as a function of soil properties. Two chemically variant soil types were chosen, based on their potential differences with respect to arsenic reactivity: an acid sand with minimal arsenic retention capacity and an alkaline clay loam with relatively high concentrations of Fe/Al and Ca/Mg. The soils were amended with dimethylarsenic acid (DMA) at three rates, 45, 225 and 450 mg/kg, and incubated for 1 year. A sequential extraction scheme was employed to identify the geochemical forms of arsenic in soils, which were correlated with the in-vitro bioavailable fractions of arsenic. Human health risk calculated in terms of excess cancer risk (ECR) showed that risk assessment based on bioaccessible arsenic concentrations instead of the traditional total soil arsenic is a more realistic approach. Results showed that soil properties (such as pH, Fe/Al content and soil texture) of the two soils dictated the geochemical speciation, and hence, bioaccessibility of arsenic from DMA, indicating that the use of organic arsenicals as pesticides in mineral soils may not be a safe practice from a human health risk perspective.     

Exposure of man to environmental selenium - an exposure commitment assessment

Selenium is an element which occurs naturally in varying concentrations in soil and is released from industrial sources, particularly from fossil fuel combustion. Harmful effects in animals and man may result from both deficient or excessive amounts of intake. Representative values of selenium concentrations in the background environment and in man are selected from available data and a pathway analysis is performed utilizing the exposure commitment method. Dietary intake of selenium is of the order of 70 micrograms d-1. With fractional absorption of 80% and retention in the body of 90% for an effective retention time of 140 days, the estimated mean body content of selenium is 7 mg. The contribution to the body burden from inhalation intake is much less significant. The exposure evaluation is performed for total selenium in the environment and in man. The parameters may be adjusted for specific selenium compounds, if data are available, and for more particular environmental and exposure conditions as required.     

Relationships between the prevalence of multiple sclerosis and some physical and chemical properties of soil

The prevalence of multiple sclerosis (MS) and some physical and chemical properties of soil in two counties of Finland have been compared. In the county where the MS prevalence rate was significantly higher, the pH of the soil was lower, the organic carbon content higher, the concentration of soluble iron, zinc, chromium and aluminium higher and those of soluble potassium, calcium, magnesium, strontium and total selenium lower than in the county with the lower MS-prevalence rate. According to the literature, areas of a high MS prevalence correspond rather closely to the global distribution of mires, particularly to raised bogs in the northern hemisphere.     

浙江吴兴区耕地土壤养分地球化学特征

文章对浙江省吴兴区耕地进行土壤养分地球化学特征分析,为吴兴区耕地合理利用及有效治理提供科学依据。通过对1960个样品进行pH、有机质、氮、磷、钾、硼、钼元素含量分析测试,发现湖州市吴兴区耕地土壤酸碱度以酸性为主,有机质含量处于中等偏高状态,氮和钼元素平均值高于浙江省平均值,硼元素平均值低于浙江省平均值,其中氮含量中等偏富集,磷元素中等,钾、硼、钼元素富集。根据土壤养分综合等级划分,研究区耕地土壤养分丰富和较丰富地区占38.11%,适中地区占52.45%,缺乏及较缺乏地区占9.44%。