四川省泥石流活动与降水因子特征

基于四川省近2008—2015年泥石流灾情和多年降水气候资料,分析了四川省泥石流的分布和降水因子特点,利用主成分分析(PCA)和K-means聚类法,对泥石流灾害所在地区降水因子(年均降雨量、降雨日数、暴雨雨量、暴雨日数、雨季雨量、当日降雨量、前3日降雨量和前3日降水和前9日降水比值)进行了分析,得到了不同降雨类型诱发的泥石流特点和分布,探求了四川省泥石流灾害时空分布规律及其与多年气候降水特征的关系。结果表明:四川省泥石流多分布于龙门山断裂带、川西高原、攀南(攀枝花和凉山州)地区和盆周东部山区,这些地区存在有利于泥石流发生的地质、地形和物源条件和水源条件;多数泥石流事件的发生与灾害前3日降水密切相关;基于聚类结果,得到四川省泥石流类型和分布特点,对四川省对不同地区开展减灾风险管理提供了科学依据和参考。     

采用地统计学和GIS技术对东北地区不同时期降水的分析

采用地统计学与GIS技术相结合的方法对东北地区146个站1961—1990年与1971—2000年的年降水和夏季降水气候值进行分析，与传统统计方法的结果对比后认为传统的统计方法不能真实地反映不同时段数据的差异。通过在GIS平台上对两组气候值差异百分比的空间分布分析得出：黑龙江西南部以及东部部分地区、吉林东南部和辽宁中部地区夏季降水量增加3%～6%，其余地区减少，其中辽宁南部和西北部减少幅度最大，达6OA～9％；黑龙江大部、吉林东部以及辽宁中部地区年降水量增加，其余地区减少，辽宁南部地区减少幅度最大，达6％～9％。     

华山地区降水特征分析与年降水量预测

该文依据华山地区1953—2013年降水资料,利用Mann-Kendall检验方法、有序聚类法、云模型等方法,结合滑动马尔可夫预测模型分析并预测了华山地区的降水特征。结果表明:华山地区月降水分布极度不均,主要集中在7月、8月、9月。冬春季降水量少,分布均匀,稳定性高;夏秋季节降水量多,分布不均匀,稳定性低;夏秋两季降水量的变化直接导致年降水量的分布不均。年降水量与3 a滑动平均年降水量均呈递减趋势,通过了99%显著性检验。滑动马尔可夫预测模型预测未来10年降水量呈增加趋势,2014—2023年预测降水量均值767.32 mm,增加幅度为29.3 mm/10 a,2019年预测值最小,为634.3 mm;2023年预测值最大,为883.31 mm。该研究可为华山地区水土流失、滑坡等自然灾害防治提供指导性建议。     

地形因素对降水分布影响的研究

在有限降水资料的基础上，研究影响降水的因素，建立降水量与各因素之间的关系，为流域内的水资源和水环境研究提供了良好的基础。以数字高程模型（DEM，Digital Elevation Model）为出发点，计算出高程、坡度、坡向，直接或间接用DEM和有限的降水资料来推求无资料地区的降水状况。将该方法和系统应用于石羊河流域，用该区域内的20个雨量站的降水资料建立模型，另外6个站点的降水资料做校核，并用模型模拟该区域内均匀分布的230个点的降水量，结果表明所建立的模型取得了理想的模拟效果。     

西双版纳热带地区不同植被覆盖地域径流特征

选择西双版纳热带地区3类不同植被覆盖小流域水文观测点，利用1995年7月－10月的水文和降水观测资料，分析了月径流特征，并选取了大暴雨，连续降水后降大雨和连续无降水后降中雨等3种情况，对热带地区不同土地利用所引起的径流变化特征进行了初步分析，为西双版纳热带地区的水土保持，森林功效等研究奠定基础，并为有效地保护和合理地利用西双版纳地区的森林资源，促进当地经济的健康发展提供科学依据。     

不同空间插值方法在阜新地区降水插值的适用性探讨

针对传统面平均降水计算方法很难考虑区域地形对降水的影响,选用可考虑地形影响的两种空间插值方法,结合阜新地区实测雨量数据,探讨各插值方法在阜新地区降水插值的适用性.分析表明:反距离插值方法在阜新地区降雨插值的适用性明显好于克里金方法,适合于阜新山丘较多地区面平均降水及无资料地区降水插值计算.     

基于GoogleEarthEngine的黄土高原植被覆盖度时空变化特征分析

[目的]探究黄土高原植被覆盖度变化的时空特征，揭示植被对气候因子变化的时滞效应，进而为地区生态保护与高质量发展提供数据支撑。[方法]基于2001年至2020年的黄土高原地区NDVI数据、气温和降水数据，利用像元二分法、一元线性回归和时滞偏相关分析等方法，开展地区植被与气候因子变化关系的研究。[结果]过去20年间，黄土高原植被覆盖度以0.076/10 a的速率增加，在空间上主要呈现极显著增加，但占总面积38.29%的区域植被覆盖变化波动较大。黄土高原月植被覆盖度与气温和降水呈现显著正相关关系，其中降水是影响植被变化的主要因素。植被对降水的响应滞后时间主要集中在3个月，而气温的滞后时间在空间上存在较大差异，东南部植被主要滞后0至1个月，而西北部植被主要滞后2至3个月。[结论]黄土高原植被变化主要受降水影响，20年间植被恢复情况良好，但变化波动较大，未来应继续生态保护工作进行巩固。     

1994年春季(3～5月)气候对我国农业生产的影响

全国大部分地区气温偏高，降水偏少，日照较为充沛。大部分时段光、温、水配合较为协调，农作物生长发育正常。北方部分地区春旱一度持续发展，不利于作物生长发育，南方大部分地区降水比较适宜。入春后，华南早稻产区持续低温、阴雨、寡照天气，江南稻区日照长时期不足，播种育秧条件较差。川滇部分地区降水持续偏少，出现明显旱情。另外，南方局部地区暴雨成灾，给当地农业生产造成较严重的影响。     

开发北方旱农地区自然降水生产潜力的主要限制因素及途径

在北方旱农地区的３个类型区域，半干旱偏见旱区、半干旱区、半湿润偏旱区，通过４年的大田试验的统计分析，明确了开发北方旱农地区降水生产潜力的限制因素，一是降水足，二是土壤肥力低下，探明了北方旱农地区降水生产潜力开发程度低，水分利用效率小；提出了以提高农田水分利用率和水分利用效率为中心的关键技术体系。     

四川省典型区域滑坡泥石流与降水的关系

[目的]对四川典型区域滑坡泥石流与降水的关系进行研究,为进一步分析四川地区气候变化与地质灾害分布规律之间的关系提供基础。[方法]四川滑坡、泥石流灾害多由降水引发,在收集整理近15a滑坡泥石流灾害事件后,确定出四川滑坡、泥石流的典型区域,进而分析典型区域滑坡、泥石流与降水气候特征的关系。[结果]四川省滑坡典型区域在川东地区,泥石流典型区域在阿坝州地区。近年典型区域滑坡、泥石流近年频次明显增加,典型区域滑坡属于较长日数降水诱发型,与15d有效降水密切相关,前期降水中,强降水所占比例较大;典型区域泥石流属于较短日数降水诱发型,与3d有效降水密切相关,前期降水中,中小型降水所占比例较大。[结论]研究区15d有效降水量和3d有效降水与降水气候特征间的关系密切,可分别作为典型区域滑坡、泥石流预报因子。     

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,     

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.     

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.