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。     

基于信息扩散理论的黑河中上游绿洲农业旱灾近20年风险评估

基于黑河中上游绿洲各县(区)1991—2010年农业旱灾受灾面积、成灾面积等统计数据,利用信息扩散理论风险分析模型和风险等级划分,对农业旱灾风险进行评估。结果表明:近20年来,研究区农业受旱灾影响的受(成)灾风险估计值随风险指数增加而减小,当受灾风险水平在50%以内时,临泽受灾风险估计值最小,为0.000 29,山丹受灾风险估计值最大,为0.811 12,风险频率达到每1.2年一遇。当成灾风险水平在30%以内时,成灾风险估计值以山丹最大,为0.765 50,达到每1.3年一遇,甘州区最小,为0.118 95,旱灾几乎年年发生。旱灾发生具有高频率和集中性特点,受损度主要集中在15%以内,受损程度在30%以上可能性很小。当旱灾受(成)灾指数为10%时,高台、民乐、山丹的灾损程度最大,而超过50%时灾损程度很小;成灾风险等级空间差异显著,表现为以甘州区、临泽为中心,风险等级水平向外围增加,即山丹、民乐风险等级水平最高,属于高、较高风险等级,甘州区、临泽风险等级水平最低,为低、较低风险等级。     

江淮分水岭地区一季稻气候生产潜力评估

为找出江淮分水岭地区水稻限制气象因子,提高研究区水稻现实生产力,利用江淮分水岭地区13个站点1980—2016年逐日地面观测资料,采用逐步订正法对江淮分水岭地区一季稻生长季光合生产潜力(Y_Q)、光温生产潜力(Y_T)、气候生产潜力(Y_W)及气候资源利用率的时空分布进行了研究,并分析了气象因子对气候生产潜力的影响。结果表明:江淮分水岭地区Y_Q,Y_T与Y_W总体呈下降趋势,气候资源利用率随时间变化呈缓慢上升趋势。江淮分水岭地区Y_Q,Y_T在空间分布上较为一致,均沿分水脊线阶梯状平行分布。江淮分水岭分水脊线西北侧为Y_Q,Y_T高值区,脊线附近地区为Y_Q,Y_T中值区,脊线东南侧为低值区。江淮分水岭地区西南部及东北部Y_W高、中部Y_W低。气候资源利用率在空间分布表现为自西向东递增。降水、日最高气温和参考作物蒸散是影响研究区气候生产潜力最主要的3个气象因子。本研究可为江淮分水岭地区一季稻种植优化调整提供理论依据。     

基于GIS的安徽省江淮分水岭区域气象干旱研究

为了解江淮分水岭地区的气象干旱情况,利用30年逐日降水数据,根据信息熵理论,计算了均态尺度和变化尺度下的标准降水指数,并进行叠加分析,统计了30年间逐日干湿等级事件数量,从而分析了江淮分水岭地区干旱发生的时空变化特点。结果表明:(1)在两种尺度叠加情况下,江淮分水岭地区"特别干"和"特别湿"等级事件缺失,干湿等级事件总体呈正态分布,越趋向极端的干湿等级事件发生的概率越小,其中,"正常"事件发生的概率均在50%以上,其他事件发生的概率均小于20%;(2)各月份中西部地区气象干旱日数占比较高,春季、冬季干事件主要发生在南部,夏秋季节干事件主要发生在西部;(3)从干湿等级发生区域来看,西部、南部易发生"轻微干"事件,西部易发生"严重干"事件。可为江淮分水岭地区的防灾减灾提供一定的科学依据。     

浙江省海岸带景观生态风险格局演变研究

海岸带景观生态风险格局演变分析,对建立生态风险预警机制、降低生态风险概率,促进海岸带地区景观格局优化具有重要意义。以1990年、2000年、2010年3个时期的TM遥感影像为景观格局分析主要数据源,构建景观生态风险格局演变模型,分析浙江省海岸带景观生态风险格局时空变化特征。结果表明:(1)1990—2010年,研究区内景观结构发生了较大的变化,耕地、海域、林地以及水域面积均呈现出下降趋势,建设用地、未利用地以及养殖用地呈现出不断增加的趋势;(2)1990年,浙江省海岸带景观以低和较低等级生态风险区为主,分别占全区总面积的50.30%和35.94%,2000年低、较低等级生态风险区面积均有不同程度减少,而中等生态风险区面积则有显著增加。至2010年,低生态风险区面积进一步减少,而高与较高生态风险区面积增加明显;(3)从风险格局演变来看,1990—2010年海岸带景观低和较低等级生态风险区的分布范围不断向陆侧后退,面积呈现下降趋势,中等、较高和高生态风险区在沿海地区不断扩展,侵占生态风险等级相对较低区域,以沿海平原的淤泥质海岸尤为典型;(4)2000—2010年生态风险等级上升的速率明显低于前10a,表明人类在加速海岸带景观开发利用的同时,已开始关注生态环境的保护,正在逐步追求经济与生态环境的协调发展。     

江淮分水岭水土流失区域生态环境质量评价

以江淮分水岭部分为研究对象,选取植被指数、干度指数、湿度分量、地表温度分别表示绿度、干度、湿度和热度等指标,结合主成分分析法构建了生态系统质量综合评价指数(CEQEI),对研究区的生态环境状况进行了综合评价。结果表明,研究区CEQEI的均值从2000年的0.357增长至2005年的0.529,继续增长至2010年的0.615,说明该区生态环境整体状况不断改善。研究表明CEQEI能够较为系统地对研究区的环境状况进行评价。     

皖江淮分水岭东部降水变化与池河流域输沙关系的研究

对皖江淮分水岭东部 195 7年以来的降水测站记录和该地区池河流域 1990年以来的降雨径流因子及输沙量资料分别进行了趋势分析和关联分析 ,发现 4 3年来 ,江淮分水岭东部降水的季节和年际变化异常显著 ,且春季降水具有明显的减少趋势 ,夏季和年总降水都有明显的增加趋势。以该地区池河流域为例 ,通过灰色关联分析揭示出径流量和日雨量 5 0～ 10 0 mm暴雨次数与输沙量的关联最为密切 ,其次是降雨量和大于 10 0 mm的暴雨次数与输沙量关联密切 ,最后是雨日天数。研究结果可为江淮分水岭地区旱灾和水土流失防治提供科学依据     

安徽省一季稻产量灾损风险评价

利用安徽省1981-2014年50个市(县)一季稻产量资料,采用直线滑动平均方法计算一季稻相对气象产量,通过正交经验分解(EOF)分析一季稻相对气象产量的时空变化特征,并从一季稻产量灾损角度出发,采用灾年平均减产率、产量变异系数、减产风险指数及区域农业水平指数作为产量灾损风险评估指标,对安徽一季稻产量灾损进行风险区划。结果表明:研究期内安徽省各市(县)一季稻产量变化趋势一致,北部增产或减产较南部明显,2005年之前安徽一季稻产量波动剧烈;不同产量灾损评估指标在空间上表现出一定的地域性和连续性,灾年平均减产率、产量变异系数和减产风险指数均表现为北部数值高于南部,区域农业水平指数呈现由东北向西南减小的趋势。根据产量灾损综合风险指数区划结果,研究区域内北部灾损风险高于南部,风险高值区和中值区主要分布在沿淮、江淮北部,风险低值区面积最广,主要位于皖南山区、沿江地区及江淮南部。     

沱江流域土壤侵蚀动态变化及驱动力分析

为了解沱江流域土壤侵蚀的动态演变规律及驱动机制,以沱江流域为研究区,基于GIS和RS技术,运用RUSLE模型测评流域2000—2018年的土壤侵蚀,对其时空动态演变规律进行了探索分析,并结合海拔、坡度、植被覆盖度、地形地貌、土地、降雨、GDP、人口等影响因子,借助地理探测器对其土壤侵蚀进行了定量归因研究。结果表明:(1)沱江流域土壤侵蚀以微度侵蚀为主,主要分布于低矮的平原和坡耕地地区;2000—2018年,微度侵蚀等级比例随时间在逐渐增大,2018年相比2000年增加了7.03%,剧烈侵蚀等级比例随时间在逐渐减小,2018年相比2000年减小了2.00%。(2)以2010年为分界点,2000—2010年和2010—2018年土壤侵蚀等级微度的变化稳定率都大于75%,两个时间段内土壤侵蚀强度等级降低的范围均大于侵蚀等级升高的范围。(3)地理探测器结果表明,不同影响因子对土壤侵蚀的解释力具有差异性,解释力最强的为坡度,达到48.32%,因子间交互作用均能增强对土壤侵蚀的解释力,坡度与土地利用、坡度与降雨量的交互最为显著,交互作用解释力分别达到61.58%,52.32%,风险探测表明坡度大于...     

基于CMIP6模式的西南地区旱灾风险未来预估

预估西南地区在全球气候变暖背景下未来的干旱变化趋势,可为西南各区域研究旱灾变化并防范未来旱灾风险提供有效参考。通过评估30个CMIP6模式对西南地区的模拟性能,挑选并计算出由10个模式组成的多模式集合平均数据,基于标准化降水蒸散指数SPEI、地形、人口、GDP和土壤含水量等指标,利用AHP-熵权组合权重法和ArcGIS的空间分析功能来构建包含致灾因子危险性和承灾体易损性的旱灾风险评估模型,对西南地区SSP126,SSP245,SSP585三种组合情景下的2021—2040年近期和2041—2060年远期的旱灾风险进行了预估。结果表明：(1)高风险区主要分布在贵州南部、云南东部以及重庆的沙坪坝、四川的温江、越西等零星地区;(2)低风险区主要分布在四川东部和相邻的重庆西部等地区,大致呈南北递减的变化趋势;(3)从近期到远期,未来3种情景组合都表现出次高和高风险区范围增大,次低和低风险区范围减少的形势。综上,全球气候变暖背景下,西南地区未来的旱灾风险整体将有加大加重的趋势,尤其是低纬度地区未来的风险性将明显加重。     

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,     

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.     

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.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

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.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

Responses of native legume desert trees used for reforestation in the Sonoran Desert to plant growth-promoting microorganisms in screen house

Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria (Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation. Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured as transpiration and diffusive resistance, when these trees were cultivated without water restrictions.