1952—2017年出山店水库上游降水时空变化

为了探究出山店水库上游流域近65 a来降水的时空变化特征,基于出山店水库上游流域13个雨量站1952—2017年的逐日降水资料,运用气候倾向率法、Mann-Kendall趋势检验、Morlet小波分析和反距离权重IDW插值法等多种方法,研究了降水的年际变化、周期性与空间分布特征。结果表明:(1)流域1952—2017年多年平均降水量为1 028.3 mm,年降水量的气候倾向率为-20 mm/10 a(p<0.05),呈显著下降趋势,从季节上看,春、夏、冬降水随时间变化呈现减少趋势,秋季的降水呈现增加趋势;(2)年降水量呈现南高北低的空间分布,而年降水量的气候倾向率的变化趋势则与之相反;(3)流域降水量变化呈现20 a左右的第一主周期,同时流域的周期性变化也存在一定的空间分布特征。近65 a来,出山店水库上游年降水量变化趋势为先增加后减少,在整个时间域上有显著的下降趋势,并呈现20 a左右的周期性变化。     

阿克苏河灌区作物理论需水量的时空分布特征

[目的]研究阿克苏河灌区作物的理论需水量的时空变化特征,为该区水资源科学管理、高效利用提供理论依据。[方法]基于灌区内1972—2014年6个气象台站的逐日气象观测数据,采用FAO修正的Penman-Monteith模型,计算参考作物蒸发蒸腾量(ET0),进行空间数据的插值分析,对阿克苏河灌区作物的理论需水量特征分别在空间和时间两个维度上进行探讨。[结果](1)阿克苏河灌区多年平均ET0介于1 118~1 241mm之间,呈现中部以北地区较低,西南部、南部地区较高的规律;(2)春季和夏季的ET0最高,5,6,7月的月均ET0合计为533mm,是作物最需要水分补给的重要时段;(3)自20世纪70年代至今,作物年均蒸发蒸腾量呈现逐渐降低的趋势,2010年以后的变化趋势较为显著;(4)灌区各季节及全年的ET0变化均呈现S形曲线分布,至2014年已接近波谷并有抬升趋势。[结论]在气候变化背景下,阿克苏河灌区作物的理论需水量随时间变化显著,春夏季受蒸腾作用影响是需要补水的关键时期,年际变化呈波动抬升趋势;在空间上亦呈现明显地带分异特点,呈南高北低的特征。     

嘉陵江流域参考蒸散的年际变化趋势及成因分析

利用嘉陵江流域1960—2013年逐日气象数据,计算该流域参考蒸散(ET_0),应用Mann-Kendal方法及突变方法检测ET_0的变化趋势及突变点,应用偏导系数法揭示了ET_0变化原因。结果表明:(1)在1960—2013年,嘉陵江流域平均ET_0减小,减小斜率是0.43 mm/a。ET_0的年际变化较为剧烈,整个流域平均ET_0在1960—2013年间经历了高—低—高的3个变化阶段。在1981年ET_0的变化趋势发生了突变,嘉陵江流域ET_0的变化过程(1960—2013年)可以分为2个阶段,1960—1981年流域的整体ET_0均值变化波动较小(0.44 mm/a),1982—2013年增加趋势明显(2.62 mm/a)。不同时间尺度统计,流域北部均属于ET_0增加区域;(2)"蒸发悖论"现象存在时空差异,从整个研究时段看,流域整体存在"蒸发悖论"现象,1981年前后两个时段分别统计,存在"蒸发悖论"现象的气象站和区域较少;(3) 1960—1981年引起嘉陵江流域ET_0变化的主导因子是风速和太阳辐射,1982年后由于气候变暖趋势明显,温度上升对整个流域的ET_0增加发挥着主导作用。     

固原市主要农作物生育期有效降水与需水量特征

由于干旱地区常年降雨资源匮乏,为提高旱区降雨资源的高效利用及更加精准的掌握该地区主要农作物的水分供需平衡状况。采用美国农业部(USDA)土壤保持局推荐的有效降水量和联合国粮食及农业组织(FAO)推荐的参考作物蒸散量计算方法、线性分析法、Mann-Kendall检验法及小波分析法,研究了固原地区近60年3种主要农作物的有效降雨量及需水量的时空变化趋势。结果表明:(1) 3种作物生育期平均有效降水分布在68.8～177 mm,玉米和马铃薯生育期有效降雨量呈减小趋势,春小麦呈上升趋势,且有效降水周期呈大—小—大的变化规律;(2) 3种作物生育期平均需水量主要分布在233.7～439.3 mm,生育期需水量均呈上升趋势,分别为2.4 mm/10 a, 0.8 mm/10 a, 2.3 mm/10 a,需水量周期也呈"大—小—大"的变化规律;(3)马铃薯、玉米、春小麦的平均水分盈亏指数为-38.0%,-57.5%,-58.7%,玉米和春小麦对灌溉的依赖程度较马铃薯高。综合考虑分析固原地区多年降水和作物需水分布特征的趋势,研究结果可以为该地区3种农作物合理种植及灌溉提供理论依据,同时为发展该地区主...     

东北地区参考作物蒸散量对主要气象要素的敏感性分析

利用国家气象局提供的地面气候资料日值数据集,通过FAO推荐的Penman-Monteith公式计算了东北地区1961-2008年生长季(5-9月)逐日的参考作物蒸散量(ET0),分析了ET0及主要气象要素的变化趋势,并通过响应曲线、敏感矩阵、敏感系数等方法分析了ET0对气温、日照时数、平均风速、平均相对湿度的敏感性。结果表明:(1)近50a来,东北地区的气温呈极显著上升趋势(P0.01),日照时数、平均风速、平均相对湿度呈极显著下降趋势(P0.01);东北地区生长季平均日ET0在以3.60mm.d-1为平均值、±0.3mm.d-1的范围内波动,总体上比较稳定,最大值出现在2001年(3.87mm.d-1),最小值出现在1990年(3.28mm.d-1);(2)当气温、日照时数、平均风速的变化量从-20%变化到20%时,ET0表现为逐渐增加的趋势,当平均相对湿度的变化量从-20%增加到20%时,ET0则逐渐减小;(3)气温、日照时数、平均风速、平均相对湿度的生长季平均日敏感系数均具有较强的空间分异特性,其中气温变化对ET0的影响最为明显,其次是平均相对湿度,日照时数、平均风速对ET0的影响较小。     

黄土高原50余年来降雨侵蚀力变化及其对土壤侵蚀的影响

采用Mann-Kendall非参数检验法和累积量斜率变化率分析等方法,分析了黄土高原1960—2011年降雨侵蚀力变化及其对土壤侵蚀的影响。结果表明:(1)黄土高原年均降雨侵蚀力呈显著下降趋势,平均年下降速率为3.64MJ·mm/(hm~2·h·a);(2)年降雨侵蚀力在空间上呈现"大者变小,小者变大"的变化趋势,以400mm等降雨线为分界线;(3)降雨侵蚀力变化不是影响河流输沙变化的主导因素,渭河、泾河、北洛河、延河、无定河和汾河的贡献率分别为1.54%,0.11%,10.87%,16.47%,5.71%;(4)不同流域降雨侵蚀力对土壤侵蚀作用程度不同,主要支流侵蚀产沙率泾河无定河渭河延河北洛河汾河。降雨侵蚀力的分布特征和变化趋势,结合不同流域侵蚀产沙率,可作为评价流域内气候变化对土壤侵蚀作用的指标。     

近50年黄河流域气温和降水量变化特征分析

利用黄河流域54个气象站点1961-2010年气象数据,探讨近50a黄河流域气温和降水量的变化趋势特征。结果表明:(1)黄河流域年降水量变化具有明显的空间差异,总体表现为上游地区增多、中游地区减少的特点。春季上游降水量呈显著增加趋势,秋季中游显著减少,冬季全流域降水量均呈显著增加趋势,其中下游增幅最大。年内降水量显著增加的时段主要集中在1-3月和12月;(2)黄河流域气温变化呈显著升高趋势,平均最高气温和最低气温变化具有明显的不对称性,平均最低气温变化对平均气温升高的贡献率大于平均最高气温。平均最高气温、平均气温和平均最低气温全流域均表现为冬季增幅最大,夏季和秋季则为流域上游增幅最大。月平均气温显著增加的站点比例最高,月最高气温显著增加的站点比例最小,且均集中在2月。(3)全流域冬季出现暖湿化趋势,春季上游出现暖湿化趋势,而秋季中游出现暖干化趋势。     

泾河上游流域实际蒸散发变化趋势及成因分析

利用泾河上游流域1973—2012年的径流和蒸发皿观测资料,验证了该区域蒸散发量存在互补关系;在此基础上,利用区域内1966—2012年的气象资料,采用蒸散发互补关系模型估算区域实际蒸散发量,并进一步分析实际蒸散发的变化趋势及成因。结果表明,泾河上游流域蒸散发互补关系显著,平流—干旱模型计算该区域1966—2012年多年平均实际蒸散发量为529.4mm,总体呈减少趋势,变化率为-4.64mm/(10a)。季节变化上,春、夏、秋季的实际蒸散发量均呈下降趋势,其中夏季实际蒸散发量下降趋势显著,冬季蒸散发略有上升。通过分析实际蒸散发与气象因子的相关关系以及各气象因子变化趋势可知,研究区实际蒸散发的变化与降水、相对湿度和日照时数呈正相关关系,而与风速的变化呈负相关,该区域年实际蒸散发减少的主要原因可能是由于日照时数减少导致太阳辐射能量下降及降水量减少使可供蒸发的水量减少。     

鞍山气象要素演变特征及其对蒸发皿蒸发影响

结合趋势非线性统计(M-K)方法及突变分析法对鞍山市近61 a气象要素演变特征进行研究,并分析气象要素对区域蒸发影响。结果表明:1)从1953—2013年鞍山市平均风速和相对湿度递减明显,递减率分别为-0. 25/10 a、-1. 18/10 a,其他要素变化显著性较弱; 2)各气象要素呈现较为明显的季节变化差异,夏季日照时数及大气压强递减明显,冬季气温较其他要素M-K统计值最大,下降趋势显著; 3)除平均风速外,其他气象要素突变年份较为一致,均在1996年出现气象突变特征点; 4)日照时数及相对湿度是影响区域年蒸发的2个关键要素;在夏季气温是蒸发影响主因,而冬季日照时数则是影响主因。     

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。     

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.     

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.     

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,     

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.