兰州市蔬菜基地土壤重金属含量及评价

通过对兰州市蔬菜基地土壤重金属Pb、Zn、Cu、Cr和As含量进行研究,以国家土壤环境质量二级标准评价其单因子和综合污染指数,结果表明,兰州市蔬菜基地土壤重金属在0～20 cm土层中As含量超过兰州市土壤背景值的139.85%,在20～40 cm土层土壤中Zn和As含量分别超过兰州市土壤背景值的19.21%和28.57%。从单因子污染指数看,在0～20 cm土层土壤中,城关区土壤As的单因子污染指数为2.242,达到了中度污染的程度,七里河区和皋兰县土壤As的单因子污染指数在1～2之间,属轻度污染;从综合污染指数分析,城关区土壤重金属综合污染指数为1.175,属轻度污染;整个兰州市蔬菜基地土壤重金属综合污染指数为0.497,属安全范围。     

贵阳市主要土壤重金属状况研究

通过对2000～2003年贵阳市的白云区、修文县、开阳县、清镇市、息烽县、乌当区、小河区以及花溪区的多个旱地的表土和底土（53个样品）中重金属元素（汞、砷、铅、镉、铬）含量进行检测，以GB／T18407．1—2001《农产品安全质量无公害蔬菜产地环境要求》为标准，采用单因子指数法及N．L．Nemerow综合指数法进行评价，分析结果表明：贵阳市无公害蔬菜生产基地的大部分土壤中的5种重金属元素的含量基本在GB／T18407．1—2001规定的范围内，但也有个别区域内土样中砷、镉含量达到了警戒线的含量范围，如白云区底土中砷的单因子综合污染指数达到0．7968、乌当区表土中镉的单因子综合污染指数达到0．7542，两者都属于0．7～1．0污染警戒线范围内。总体土壤的表土、底土重金属综合污染指数分别为0．3785、0．4204，小于0．7，污染等级属于安全，污染水平为清洁，土壤环境质量为1级。     

平原农区空心村典型土壤的重金属污染评价——以山东省禹城市为例

空心村整治是农村土地综合整治的重要内容,在以土地可持续利用为核心的目标导向下,揭示空心村内典型土壤重金属污染情况是整治工作特别是构建耕层土体的先导环节。本文以黄淮海平原农区的禹城市为例,分析典型空心村在整治时可能涉及的村内道路、晾晒场院、坑塘底泥、林地表土、院落农地、院落实土、土墙墙体等7种土壤的As、Cd、Cr、Cu、Ni、Pb、Zn含量,利用单项污染指数和综合污染指数,按照有关国家标准,评价其重金属污染程度,为空心村改造中土壤的安全、合理利用提供依据。结果表明:前述7类参试土壤中,除院落农田的污染指数为0.85(污染等级为Ⅱ,属"较清洁"土壤)外,其余6类的综合污染指数均0.7(污染等级为Ⅰ,属"清洁"土壤),可直接用于空心村整治中的耕层土体重构。本研究基于整治利用导向进行了平原农区空心村典型土壤类型划分,揭示了其重金属污染状况,对于科学开展空心村整治、建设更加安全的高标准农田具有重要参考价值。     

湖北贝母种植土壤和药材中有机农药及重金属残留分析

对湖北贝母种植基地土壤及药材中有机农药与重金属含量进行了测定。研究结果表明,土壤中重金属和有机农药的单项污染指数P<1,污染分担率排序为:铅(35.83%)>砷(19.26%)>汞(16.06%)>铬(15.23%)>镉(5.39%)>铜(3.66%)>滴滴涕(2.28%)>六六六(2.10%),综合污染指数P综=0.29<0.7,属安全级,为清洁水平,符合国家标准。湖北贝母药材中重金属和有机农药含量均低于绿色行业标准,有机农药富集能力较强,药材中重金属砷、铅、铬和有机农药残留滴滴涕的含量与土壤中含量显著相关,相关系数分别为0.924、0.852、0.90和0.843。     

复垦土壤重金属污染潜在生态风险评价

为揭示矿区复垦土壤中重金属元素潜在的污染特征,采用Hakanson 潜在生态风险指数（The Potential Ecological Risk Index）,对安太堡露天煤矿复垦土壤中Cd,Cr,Cu,Pb,Hg,As等6种污染元素进行了分析,研究了露天煤矿复垦土壤重金属污染程度及潜在的生态危害性。结果表明：安太堡露天煤矿不同复垦时间和复垦模式下不同层次的复垦土壤的综合污染程度范围为8.29～16.90,平均值为10.72,处于中等的污染程度。重金属潜在风险指数在131.43～331.03之间,平均191.68,生态风险达到了中等程度,特别是复垦13年的南排1?420退化平台,综合潜在生态风险指数为331.03,达到了较高程度。0～40 cm土层的潜在生态风险综合评价属于中度的潜在生态风险。Hg是主要的污染因子,其对潜在的生态风险指数所贡献的比例达到了72.5%～84.62%。其余重金属的生态风险较低。因此,在安太堡露天煤矿复垦土壤中,Hg是最主要的潜在污染因子,应采取一定的措施,防止Hg的污染。应用该体系对复垦土壤重金属污染生态风险评价所得的结论同其它研究结果互为补充和借鉴。     

安徽省某市农田土壤与农产品重金属污染评价

为评价安徽省某市农田土壤与农产品重金属污染水平,在研究区内共布设1933个点位,采集土壤样品并在污染农田中采集43个农产品样品,对其与土壤进行一对一检测,分析研究Cr、Pb、Cd、As和Hg 5种重金属含量,对研究区农田土壤重金属含量水平、空间分布特征以及农产品重金属含量与土壤性质的关系进行分析。结果表明:研究区农田土壤中Cr、Pb、Cd、As和Hg的平均含量分别为62.5、32.6、0.209、8.85、0.080 mg·kg~(-1),点位超标率分别为0.05%、0、14.59%、0.67%和1.97%。根据单因子污染指数法评价研究区农田土壤污染情况,5种元素污染程度CdHgAsPbCr,从内梅罗综合污染指数来看,所有点位中清洁的占78.58%,综合生态风险指数法评价结果显示研究区基本处于轻微生态危害水平。农产品中Cr、Pb、Cd和As 4种重金属元素都是在偏酸性的土壤上富集系数较大,而Hg在偏碱性土壤上富集能力较强。     

北京市农业土壤重金属状态评价

以北京市土壤重金属背景值为标准,对比分析了农业土壤中Cr、Ni、Cu、Zn、As、Cd、Ph、Hg 8种重金属的含量及累积情况,并采用单因子污染指数法和综合污染指数法进行了土壤重金属污染评价。结果表明,北京市农业土壤存在着一定的Cr、Cu、Zn、As、Cd累积趋势,其含量的平均值分别为53．61、21．95、65．42、9．14、0．125mg·kg^-1,比相应的背景值高79．9％、17．4％、13．8％、28．9％、5．0％;Ni和Pb的累积则不明显,平均值比相应的背景值低7．9％、29．2％,分别为24．84和19．04mg·kg^-1;而Hg含量的平均值与背景值一致,为0．08mg·kg^-1。从单因子评价结果来说,Cr污染指数在1．06-2．93之间,所有的样点都处于轻度或中度污染状态;As、Cu、Zn、Cd的污染指数相对较小,平均值分别为1．29、1．17、1．13、1．05,有50％以上的样点处于轻度污染状态;而Ni、Ph、Hg的污染指数均小于1,有60％以上的样点处于清洁或尚清洁状态,污染较轻。若从综合评价结果来说,综合污染指数处于0．96～2．16之间,平均值为1．45,几乎所有的土壤样点都属于轻度污染状态。     

云南省某锡矿废水污灌区土壤重金属污染评价分析

为揭示工矿企业污水灌溉对土壤环境质量的影响,以锡矿企业废水污灌区为例,对其表层土壤重金属Hg、As、Cd、Pb、Cr含量及pH值进行测定分析。对照国家《土壤环境质量标准》二级标准,采用标准对比法、单因子污染指数法和综合污染指数法,对污灌区土壤环境质量进行了评价。结果表明,研究区土壤pH值介于3.83～6.45之间,均值为5.14,土壤偏酸;Hg和Pb单因子污染指数全部样本为一级,土壤清洁且安全;Cr和Cd单因子污染指数分别有2.22%和4.44%的样本为二级,达到警戒级,说明土壤尚清洁,未受到污染;As单因子污染指数2.22%的样本为三级,Pi跃1,达轻污染级,为主要污染因子,表明土壤已受到As轻度污染;研究区综合污染指数值为1.16,达到轻度污染级。     

苏南某冶炼厂周边农田土壤重金属分布及风险评价

选择江苏南部冶炼厂周边污染的水稻田,采集耕层0～15cm的土壤,分析土壤中重金属Cd、Pb、Hg、As、Zn、Cu的污染程度及其空间变异特征。结果表明,土壤Cd、Pb、Cu、Zn、Hg的全量随着距污染源距离的增加而减少,呈现由东北向西南扩散的趋势,As则是由西北向东南扩散。6种重金属中Cd、Hg的污染范围相对较大,Zn的污染范围最小。DTPA浸提的6种重金属有效态含量都是距污染源距离越远而越少。采用内梅罗综合污染指数法对土壤中的重金属进行风险评价,土壤重金属的综合污染指数为39.27,污染程度已超过5级,为重度污染,其中Cd、Hg污染最为严重,含量范围分别为3.98～44.58mg·kg-1、0.36～2.01mg·kg-1,As为中度污染,Pb、Cu、Zn则为轻度污染,说明研究区域农产品安全生产存在很大的风险。     

湖北茶园土壤重金属污染状况评价

对湖北省96个茶园土壤的Cd、As、Pb、Cr、Cu、Ni、Zn、Se、Co、V和Sb等重金属含量进行测定,并对比土壤环境质量评价国家标准,采用单因子污染指数和内梅罗综合污染指数法,对茶园土壤重金属污染状况进行了评价。结果表明,湖北省茶园土壤质量状况良好,处于清洁级和尚清洁标准的茶园比例分别为45.8%、30.2%,除1个茶园的Pb出现重度污染外,其余重金属含量均未超标。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.