黄河中游窟野河流域水沙关系变化特征及其成因分析

为探讨人类活动和气候变化对窟野河流域水沙情势的影响,基于1956—2019年窟野河流域降水量、径流量和输沙量等监测数据,运用累积距平法、双累积曲线等方法对窟野河流域水沙变化的特征及其成因进行了分析。结果表明:窟野河流域降水量随时间变化呈不明显减小趋势,而径流量和输沙量随时间变化却呈显著减小趋势,流域水沙减少的因素不是气候变化引起的降水因素; 径流量和输沙量年际变化的转折年份为1979年和1997年; 同基准期A(1956—1979年)相比,B时期(1980—1997年)气候变化对径流量和输沙量的贡献率分别为14.25%,14.22%,人类活动对径流量和输沙量的贡献率分别为85.75%,85.78%,C时期(1998—2019年)气候变化对径流量和输沙量的贡献率分别为8.76%,6.65%,人类活动对径流量和输沙量的贡献率分别为91.24%,93.35%,降水变化和人类活动都是造成窟野河流域水沙减少的影响因素,其中流域内逐年增强的人类活动是窟野河流域径流和输沙减少的主要因素,而气候变化引起的降水减少是次要因素。     

BP神经网络在渭河水环境质量评价中的应用

为准确和客观地评价渭河水环境质量状况,将改进算法的BP神经网络引入地表水环境质量评价领域,采用渭河2010年(9月7日至10月11日)水质指标监测数据,构建了渭河水环境质量评价模型。通过3个水质监测项目(氨氮、高锰酸盐指数、溶解氧)对渭河水质进行了评价,评价结果与环境保护部公布结果完全一致。结果表明,BP神经网络应用于水环境质量评价具有客观性、通用性和实用性,可以很好地解决评价因子与水质等级间复杂的非线性关系,评价方法简便可靠,预测精度高。     

苍溪县工业园水环境评价及污染防治对策

水环境评价和预测是水资源规划管理的重要内容之一,对促进水资源可持续利用具有重要现实意义。以苍溪县工业园地表水环境监测数据为基础,应用单项标准污染指数法对跌马桥沟地表水环境的影响进行评价,并采用完全混合模型和一维稳态水质模型相结合的方法对排污口下游的地表水进行预测;最后对结果进行了初步分析,并提出了相应的污染防治对策,以期为制定水环境宏观决策及区域经济发展规划提供必要的科学依据。     

陕西省彬长矿区水土流失与地质灾害的关系初探

煤炭开采造成矿区水土流失加重。矿区环境地质灾害类型复杂,危害严重。以陕西省彬长矿区(位于长武、彬县和旬邑3县境内)为例,在阐述该矿区水土流失程度及特征的基础上,分析了其水土流失与环境地质灾害的关系;煤矿区水土流失往往以地质灾害为成因,地质灾害加重了水土流失的程度。总结了矿区滑坡型、崩塌型、泥石流型、地面塌陷型水土流失4种类型及其特点,提出了矿区地质灾害防治思路及治理对策。针对采空区、地表塌陷、地裂缝、弃渣场等煤矿区废弃地,应采用复垦成套工艺技术,减少水土流失的场所,同时严格控制弃土弃渣的堆放,避开水流路线,修建拦挡设施。边坡开挖要采取顶部排水及底部支护。     

基于SWAT和PLUS模型的窟野河流域径流对土地利用变化的响应及预测

[目的]为揭示窟野河流域径流对土地利用变化的响应,并预测未来径流变化。[方法]以窟野河流域为研究区,基于SWAT和PLUS模型,通过2000年、2005年、2010年、2015年、2020年和预测得到的自然发展情景下2025年、2030年7期土地利用数据,定量分析径流在不同土地利用情景下的变化。[结果](1)SWAT模型率定期和验证期的R²和NS均>0.7;PLUS模型总体精度为0.877 4,Kappa系数为0.802 1,2个模型在窟野河流域适用性较好;(2)2000—2020年,窟野河流域林地、建设用地面积分别增加102.92,600.90 km²,耕地、草地、水域和未利用地分别减少277.15,366.25,40.44,19.98 km²;(3)窟野河流域年平均径流深整体呈现“上游低,下游高,西部低,东部高”的空间分布格局;(4)在保证其他输入数据不变的情况下,改变土地利用数据,情景分析结果表明,林地、草地面积减少会促进径流,建设用地面积增加同样会促进径流;(5)自然发展情景下,2025年和2030年窟野河...     

窟野河流域径流变化及人类活动对其的影响率

利用王道恒塔、温家川2个水文站的实测降水、径流资料,应用M—K秩相关系数、R/S分析、降水—径流双累积曲线法等多种数值模型方法,分析了窟野河径流年际变化特征、径流变化趋势、降水变化以及人类活动对径流变化的影响。结果表明:(1)窟野河流域多年径流变化呈下降趋势,20世纪末以来尤为明显。(2)王道恒塔和温家川2个水文站的Hurst指数分别为0.853和0.803,表明未来一段时间内窟野河年径流变化趋势将与过去保持同一势态,有持续递减的特征。(3)不同历史阶段,人类活动的剧烈程度不同,对径流量减少的影响亦不同。影响最剧烈的阶段为1997—2010年,该阶段人类活动对径流减少的影响所占比例在2个水文站分别高达80.48%和93.62%。人类活动的加剧是导致窟野河径流量锐减的主要原因。     

陕北地区水资源及其可利用量计算分析

为了缓解陕北地区水资源短缺与社会经济发展的矛盾,对该地区水资源及可利用量进行了研究.分析了陕北地区水资源的基本特点及利用现状.采用地表水资源量减去河道内生态基础流量和汛期下泄洪水量的方法,计算了陕北地区的地表水资源可利用量和水资源可利用总量,总结了二者的分布特征,并讨论了其它水资源的利用现状及未来趋势.研究结果表明,陕北地区水资源可利用量很少,仅有1.6×109 m3,可利用率也只有40％,水资源及其可利用量主要分布在榆林地区.     

湘西古丈烂泥田锰矿区地表水污染特征及风险评价

[目的]研究古丈县烂泥田实施无尾矿库锰矿综合治理后地表水质量,以期掌握研究区地表水安全状况,为锰矿区重金属的污染治理提供依据。[方法]对采集水样的pH值, Mn,Pb,Hg,As,Cu,Cd,Cr~(6+),化学需氧量及氨氮含量进行测定。运用水质综合污染评价法与健康风险评价法对样品结果进行评价。[结果]①古丈烂泥田锰矿区地表水中仅S_3(涵洞出口上游),S_4(恒源矿业下游)与S_5(烂泥田河流末端)号采样点的Mn含量超过《地表水环境质量标准》(GB 3838-2002)中Ⅲ类标准;②受张氏锰业外排废水的影响,各样点水环境综合污染指数大小顺序为:S_3(涵洞出口上游)S_4(恒源矿业下游)S_5(烂泥田河流末端)S_1(锰矿渣库上游)S_2(涵洞出口);③S_1—S_5号采样点水环境总健康风险(RT)分别为7.73×10~(-6),1.19×10~(-5),4.23×10~(-5),2.64×10~(-5),2.40×10~(-5),均未超过国际辐射防护委员会(ICRP)的最大可接受风险水平(5.0×10~(-5))。[结论]水环境的总体健康风险主要来源于非致癌物质。减少水环境中的铅和铜,可以有效地控制饮用水带来的总体健康风险。从总体上看,古丈县烂泥田无尾锰矿实施一体化管理已达到目标,水环境质量基本达到标准。     

浅谈黄河中游多沙粗沙区重点支流的生态环境建设

“两川两河”(皇甫川、孤山川、窟野河、秃尾河)流域水土流失治理是黄河中游多沙粗沙区生态环境建设的重中之重。加强这一地区的生态环境建设,对减少入黄泥沙,改善当地生态环境,实施西部大开发战略具有十分重要的意义和必要性。在对该区自然特征及土壤侵蚀特征分析的基础上,初步提出了生态环境建设的基本思路、防治目标及措施布局     

黄河中游粗泥沙集中来源区重点支流的遴选

通过来沙粒径、输沙模数、水土流失面积占流域面积的比例等指标遴选出黄河粗泥沙集中来源区重点治理的支流。按水文站实测悬移质粒径粗细分析的重点支流的排序为:皇甫川、窟野河、秃尾河、佳芦河、孤山川、无定河、延河和清涧河;根据各支流坝地淤积物钻孔取样分析的d≥0.10 mm泥沙所占百分数由大到小排序是:窟野河、皇甫川、清水川、孤山川、石马川、秃尾河、无定河、佳芦河、乌龙河、延河和北洛河;在此基础上,再按粗泥沙输沙模数大小最后遴选的重点治理支流的顺序是:窟野河、皇甫川、清水川、秃尾河、孤山川、石马川、佳芦河、乌龙河、无定河。     

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,     

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.     

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.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

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.