南方农牧交错带降水变化及旱涝多时间尺度特征

[目的]分析南方农牧交错带降水变化及旱涝多时间尺度特征,为该区旱涝灾害防治决策、牧区生态重建及保护提供科学参考。[方法]基于南方农牧交错带1960—2017年20个气象站点逐月降水量资料,采用标准化降水指数(SPI)、反距离权重插值、M-K突变检验等方法对南方农牧交错带近58 a的降水特征及旱涝灾害时空格局进行研究。[结果]①近58 a以来南方农牧交错带年平均降水量以3.98 mm/10 a的速率在增加,降水主要集中在夏季,用M-K方法检测出该区域年平均降水量在1990年发生突变;②受气候、大气环流、地形、海拔高差、下垫面等因素的影响,降水量在空间分布上以维西—理塘—若尔盖为界,西北部降水量少,东南部降水量多,降水量呈现出由东南向西北递减的趋势;③研究区年降水量的增减变化以松潘—马尔康—新龙—理塘—稻城一线为界线,该线以东地区的年降水量均呈显著增长趋势发展,以西地区的年降水量呈显著减少趋势;[结论]研究区20世纪60—70年代旱灾发生的频率略高,80—90年代涝灾发生的频率较高,2000年以来旱涝灾害呈明显的减弱趋势发展。     

广东省旱涝灾害时空变化特征研究

[目的]研究广东省旱涝灾害时空变化特征,并对广东省1960—2012年旱涝等级进行划分。[方法]应用小波分析、马可尔夫链、Mann—Kendall突变检验、经验正交函数以及克里金空间插值法等方法。[结果](1)在时间上,广东省年降水量呈上升趋势,存在28,13和6a的时间尺度上的震荡周期;(2)广东省旱涝灾害发生频率及未来几年旱涝状态与气温变化有良好的响应关系。(3)在空间上,粤东地区和粤西地区以涝灾为主,而广宁—广州—台山地区一带以旱灾为主。[结论]广东省旱涝灾害与气温变化存在一定的响应关系,气温突变后旱涝灾害增多。     

川滇地区气候特征与旱涝灾害变化趋势分析

以川滇地区70个气象观测站点1961-2011年的降水、气温资料为基础,采用线性回归、M-K突变检验、反距离加权空间插值、小波变换等方法,分析了川滇地区近51a来气候变化特征和旱涝灾害趋势。结果表明:(1)近51a来川滇地区气温总体上呈增加趋势,气温倾向率为0.21℃/10a,增温趋势系数高达0.71,气温存在极其显著的长期增温趋势。川西高原年平均气温最低,云南省南部地区气温最高,海拔高度是影响该区气温空间差异的重要因素。(2)近51a来川滇地区降水量总体上呈减少趋势,平均递减率为10.76mm/10a。受西南季风与海拔高度的影响,降水量在空间分布上差异极大,川西高原与四川盆地西南周边地区降水量相对较少,四川盆地降水相对丰富,滇西南地区降水量最为充沛。(3)川滇地区气候暖干化趋势明显,分别在1997和1999年发生了增温和降水量减少的突变,旱涝灾害存在10~15a和28a的周期振荡,该区涝灾向旱灾转化的趋势明显。     

江淮分水岭地区旱涝灾害致灾气候阈值分析

采用江淮分水岭及周边地区1960—2010年14个气象站点的逐日降水量数据,运用涝灾阈值法和SPI指数(标准化降水指数)法,确定了旱涝灾害致灾气候阈值,分析了不同等级旱涝灾害时空分布特征,同时结合1989—2010年区域农作物受灾情况,进一步探究了致灾气候阈值与农作物受灾面积之间的关系。采用1960—2010年降水量数据计算得到了江淮分水岭地区5级涝灾致灾气候阈值,通过SPI指数确定了旱灾致灾气候阈值。对比分析结果显示,典型旱、涝灾年份旱、涝灾空间分布情况与实际情况较为吻合,说明两种旱涝阈值方法都适用于江淮分水岭地区旱涝灾害分析。进一步通过构建致灾气候阈值与农作物受灾面积之间的关系模型,发现旱灾致灾气候阈值与实际旱灾受灾面积之间存在着较高的相关性,而涝灾致灾气候阈值与涝灾受灾面积之间相关性相对较小。     

厄尔尼诺/拉尼娜事件对山西省南部地区气候的影响

根据1961年以来的气温和降水资料,结合小波分析和发生的厄尔尼诺/拉尼娜事件,分析了1961年以来山西省南部地区气温和降水的变化趋势、周期以及厄尔尼诺/拉尼娜(El Nino/Southern Oscillation,ENSO)事件对山西省南部地区气温、降水量以及旱涝灾害的影响。研究结果表明,1961年以来山西省南部年平均气温总体呈波动式上升,上升速率为0.34℃/10a,而年平均降水量总体呈下降趋势,下降速率为23.4mm/10a。小波周期分析显示,山西省南部气温变化的周期约为3,8,20和25a,降水量变化的周期约为3和7a。厄尔尼诺年山西省南部年平均气温升高,降水量显著减少,而拉尼娜年气温下降,降水量略有增加。该区在厄尔尼诺年易发生旱灾,而拉尼娜年易发生涝灾,且旱涝灾害多分别发生在连续性的厄尔尼诺年和拉尼娜年。     

岷江流域降水特征与旱涝灾害趋势分析

基于岷江流域14个气象站点1961—2012年逐月降水资料,采用数理统计方法结合GIS空间分析技术,对流域降水量时空演变特征进行了分析,利用不同尺度的标准化降水指数（SPI）对流域旱涝特征进行了研究。结果表明:（1）近52 a来,岷江流域年平均降水量呈显著减少趋势,减少倾向率为20.18 mm/10 a;流域年均降水量在1993年发生突变,降水量显著减少。（2）该流域降水量由东南向西北呈递减趋势,以松潘—小金—康定为界,该线以西地区年降水量为616～1 000 mm;该界线以东地区年降水量为1 000～1 732 mm。（3）以松潘—小金—康定为界,该界线以西降水量呈增加趋势,增加倾向率为0～27.11 mm/10 a的范围内;该界线以东降水量呈减少趋势,减少倾向率在0～80 mm/10 a的范围内。（4）岷江流域旱涝灾害阶段性变化趋势明显,1961—1967年涝灾频繁,1968—1972年干旱频率高,旱灾严重;1973—1993年涝灾频繁;1994—2012年旱灾程度与频次均呈增加趋势,旱灾严峻。（5）岷江流域旱涝灾害总体以1990年为转折点,1990年以前该区多涝灾,1990年后多旱灾,岷江流域由涝灾向旱灾转化的趋势明显,在未来一段时间应做好防旱抗旱工作。     

厄尔尼诺/拉尼娜事件对青海湖周边地区气候的影响

根据1961年来青海湖周边地区的气温和降水量资料,结合小波分析和ENSO事件的发生与变化,研究了1961年来青海湖周边气温与降水的变化趋势,以及厄尔尼诺/拉尼娜事件对该区气温、降水量以及旱涝灾害的影响.结果表明,1961年来青海湖周边地区的年降水量呈波动上升趋势,西部最显著,年降水量以8.73 mm/10 a的速率增加.该地区的年平均气温呈波动上升趋势,平均气温增温率接近或明显高于全国平均水平.1988-2010年多年平均气温比1961-1987年增加更显著.小波分析显示,青海湖周边地区降水变化周期约为3,7和17a,气温变化的周期约为3,7和29 a.不同研究区域的降水量和气温变化与ENSO事件相关性不同.研究数据表明,青海湖周边地区厄尔尼诺年发生涝灾多于旱灾,而拉尼娜年多发生旱灾.1961-2009年青海湖水位总体趋势在下降,2005年后出现回升,流域降水量对湖水位的年变化有显著影响.     

宁夏地区气候暖干化与旱涝灾害趋势的关系

依据宁夏地区11个气象站点1961—2012年实测气象数据,利用趋势线法、Z指数法、Mann—Kendall突变检验法及马尔科夫模型对宁夏地区气候变化特征和旱涝趋势进行了分析和预测。结果表明:(1)近52a来宁夏地区气候经历了冷湿—暖湿—暖干的转变,气温呈显著波动上升趋势(0.36℃/10a),远高于西部平均变暖率(0.2℃/10a);降水呈波动下降趋势,下降速率为9.94mm/10a。(2)旱涝灾害发生频次与气温变化具有一定的同步性。20世纪60—80年代中期气温变化不明显,旱涝趋势稳定;80年代中期到2006年气温大幅上升,旱涝灾害同步增加;2006—2012年增温趋势有所减缓,旱涝灾害相应减少。(3)运用马尔可夫模型对未来5a的旱涝状态进行了预测,结果表明,2013—2017年该地区降水处于"正常"的概率较大。在气候暖干化的大背景下,未来宁夏地区旱涝灾害发生频率有可能进一步增加。     

秦巴山地气候变化特征与旱涝区域响应

[目的]气候变化对自然环境和人类活动产生重要影响,厘清全球变化背景下极端气候灾害发生的频次和强度对于维护人民生命财产安全具有重要意义。[方法]根据1970—2017年秦巴山地内102个气象站点的逐日数据,运用线性回归、Mann-Kendall非参数检验、反距离权重法(IDW)、Z指数法和Morlet小波变换等方法,分析近48年秦巴山地气候变化特征及西部大起伏高山区、秦岭大起伏高中山区、大巴山大起伏中山区和豫西汉中中山谷地4个地貌单元上的区域旱涝灾害响应研究。[结果]近48年来秦巴山地气温以0.3℃/10 a增加,降水以0.87 mm/10 a的速率增加,全区气候朝暖湿化趋势发展。研究时段内,不同地形区气温都呈上升趋势,但增加速率不同,大巴山大起伏中山区增速最大(0.7℃/10 a)、豫西汉中中山谷地最低(0.2℃/10 a),从降水量及变化趋势来看,大巴山大起伏中山区降水量明显高于其他地形区,变化倾向率最大(13.45 mm/10 a),西部大起伏高山区变化倾向率最低为0.06 mm/10 a。秦巴山地旱涝灾害发生的程度年际差异明显,且1970—2017年有加剧的趋势,4个区域旱涝灾害...     

湖北省降水及旱涝时空分布特征分析

为更加全面地了解湖北省降水和旱涝时空分布特征,基于湖北省30个雨量站资料,采用M-K趋势检验、Morlet小波、Z值法及EOF等分析计算方法,对全省1960—2013年降水变化显著性、周期性及空间分布变化进行了研究,并分析了湖北省单站旱涝、区域旱涝等级、空间旱涝分布及30个站点旱涝Z值空间分布模态。结果表明:全省近50年降水量整体呈略微减少的趋势,但减少趋势不显著,降水倾向率为2.92 mm/10 a,空间上呈现东南部和西南部较多,且中东部地区降水呈增加的演变趋势;在此驱动下,全省呈现出旱涝交替频发,东南部易发生涝灾,西北地区易发生旱灾的整体特征;且通过旱涝Z值的EOF正交分解分布图发现,全省旱涝分布呈一致型、西北和东南方向相反型和自西北向东南呈"三明治"型的规律,其贡献率分别为50.23%,16.14%,5.59%。     

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。     

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.     

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.     

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,     

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,     

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.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.