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1.
耕地保护是我国粮食安全的根本保障。然而,在快速城市化背景下,耕地保护导致生态用地加速流失造成对生态系统服务功能的影响往往被忽略。以武汉市为例,采用模型模拟的方法,利用基于元胞自动机的土地利用变化模型——LANDSCAPE模型设定严格、适度耕地保护情景,进而基于InVEST模型定量评估耕地保护对生态系统水源涵养功能的影响,为科学认识耕地保护政策的实施对生态系统服务功能的影响提供新的视角。结果表明:（1）严格、适度耕地保护情景下武汉市2020年生态系统水源涵养功能存在显著差异。相较于适度耕地保护情景,严格耕地保护情景下,位于武汉市东北地区的低水源涵养区分布范围明显增多,高水源涵养区分布明显较少;（2）在水源涵养总量方面,严格耕地保护情景下的水源涵养总量为4.33×108 m3,适度耕地保护情景下的水源涵养量为4.58×108 m3,两者差异显著。（3）严格、适度耕地保护情景中草地、林地、水体等生态用地的水源涵养总量分别为1.06×108 m3,1.27×108 m3。其中林地水源涵养量最高,水体、草地次之。  相似文献   

2.
黑河流域水资源供需平衡与配置研究   总被引：2，自引：0，他引：2  
水资源合理配置是水资源高效利用的重要手段,同时是水资源可持续利用的核心问题。针对黑河流域水资源利用现状与存在的问题,运用系统分析理论与方法,对黑河流域水资源需求、供水能力、水资源配置与供需平衡进行了分析与讨论。结果表明:在50%保证率下,黑河流域2015年、2020年和2030年需水量分别为3.271×109 m3,3.041×109 m3和3.071×109 m3,供水量分别为2.841×109 m3,2.972×109 m3和3.033×109 m3,缺水量分别为4.30×108 m3,0.69×108 m3和0.38×108 m3,缺水率分别为13.15%,2.27%和1.24%。针对流域水资源现状,应采取提高工业用水重复利用率、调整农业种植结构、大力发展高效节水技术等措施。继续加强流域水资源高效管理,改善流域生态环境,提高流域内水资源可持续利用能力。  相似文献   

3.
使用便携式光合系统仪LI-6400测定西藏川滇高山栎净光合速率的日变化及其对环境因子的响应。结果表明:川滇高山栎的净光合速率在11:00点左右达到最大值,然后逐渐下降,到20:00左右净光合速率降到0以下,转入暗呼吸。从川滇高山栎的日进程可以看出,叶片出现明显的“午睡”现象。在温度（15.5±2）℃,大气CO2浓度386.5 μmol/mol和相对湿度48%±5%的条件下,光补偿点为22 μmol/（m2·s）左右,光饱和点在1 029 μmol/（m2·s）左右。在大气CO2浓度为381.5 μmol/mol,相对湿度为48%±5%,光强800 μmol/（m2·s）的情况下,15~30℃川滇高山栎的净光合速率都是比较高的。  相似文献   

4.
高寒草甸土壤微生物功能多样性对氮肥添加的响应   总被引：2，自引：0，他引：2  
采用Biolog-ECO生态板法研究了4个施N水平[0 g/m2（CK）,10 g/m2（N10）,20 g/m2（N20）,30 g/m2（N30）]下土壤理化性质和微生物功能多样性的变化规律。结果表明:中高水平氮肥添加显著增加了速效氮、速效磷含量和根土比,但降低了土壤含水量。施N肥0-10 cm土层平均颜色变化率降低,而10-20 cm土层则被提高,且N20最大。施N肥后降低了0-10 cm土层土壤微生物Shannon-Wiener指数、Pielou指数和McIntosh指数,但10-20 cm土层则被提高。PCA分析表明,施N肥改变了土壤微生物代谢功能类型,糖类、氨基酸、酸类是土壤微生物主要利用的碳源类型。RDA分析表明,在0-10 cm土层,土壤含水量和全氮是影响土壤微生物功能多样性的主要因子,而10-20 cm土层主要受土壤含水量和速效磷的影响。综上,施N肥增加了土壤的有效养分含量,进而改变土壤微生物功能多样性、碳源利用能力和数量。  相似文献   

5.
用球墨铸铁屑处理含铬废水的试验研究的结果表明:当含铬废水Cr6+含量为4.5mg/L时,其Cr6+去除率>90%,出水Cr6+含量≤0.42mg/L,小于国家标准的0.5mg/L;当温度为21℃、铁屑粒度为1.2～2.0mm时的最佳工艺方案为:进水pH值为2.0～2.4,出水沉淀时pH值为8.0～9.0,接触时间为15～21min。  相似文献   

6.
[目的]探究滇中尖山河流域退耕还林措施下不同地类侵蚀性降雨、氮磷流失浓度、流失量的动态变化特征,对评价退耕还林生态工程对流域水体保护和面源污染的削减效应具有重要的指导意义。[方法]选择抚仙湖湖区典型流域尖山河小流域为研究区,以流域内退耕还林/坡耕地、人工林、灌木林和次生林为研究对象,对流域不同土地利用类型径流小区进行连续三年(2017—2019年)雨季(5—10月)定量监测。[结果]退耕还林后年侵蚀性降水量和年径流量分别降低37.16%和42.75%,产流量降低95.88%和94.29%。各态氮磷输出浓度分别削减：总氮34.32%、硝态氮32%、铵态氮61%、总磷73.4%和磷酸盐70.4%;各态氮磷输出量分别减少了总氮70.40 mg/m2,硝态氮41.24 mg/m2,铵态氮20.56 mg/m2,总磷162.16 mg/m2和磷酸盐107.38 mg/m2,削减率分别为：79.29%,80.48%,88.20%,95.66%和97.06%。未退耕还林前坡耕地总氮、硝态氮、...  相似文献   

7.
[目的]探究不同浓度PAM的防侵蚀效果，进而为东北黑土区土质堤防治理提供理论依据。[方法]采用人工模拟降雨试验，共设置2个降雨强度(60,90 mm/h),5个PAM浓度(0,2,3,4,5 g/m2),观察不同雨强下PAM对坡面产流产沙、坡面侵蚀特征的影响，分析了各侵蚀形态下的水力学参数。[结果](1)在同一PAM浓度下，坡面平均产流率、平均产沙率随雨强的增大而增大。(2)在两个雨强下，平均产流率存在拐点，3 g/m2的平均产流率最小；平均产沙率随着PAM浓度的增长而降低，5 g/m2平均产沙率最小。(3)降雨强度60 mm/h,坡面的侵蚀形态主要表现为溅蚀和面蚀；降雨强度90 mm/h,坡面侵蚀特征表现为面蚀，部分伴有细沟侵蚀。(4)雷诺数(Re)小于500,均为层流，弗罗德数(Fr)小于1,属于缓流。降雨强度对水流剪切力、水流功率和单位水流功率的影响均大于PAM浓度。[结论]东北黑土区坡面施加PAM,可有效改良土壤结构，土壤水分入渗能力增强，减少了坡面侵蚀产沙，对于土质堤防侵蚀防治起到了一定的效果。  相似文献   

8.
为解决高寒矿区恢复植被退化和土壤肥力下降等问题,选用颗粒有机肥与牧区羊圈羊板粪作为试验材料,对青海木里矿区不同坡度改良土进行双因素随机区组控制试验,以期为高寒矿区生态恢复提供理论依据。羊板粪与矿山渣土配比设置4个水平,分别为0∶10(0 m3/m2,S0)、1.5∶10(0.03 m3/m2,S1)、3∶10(0.06 m3/m2,S2)、4.5∶10(0.09 m3/m2,S3),颗粒有机肥施用量设4个水平,分别为0 kg/m2(M0)、1.2 kg/m2(M1)、2.4 kg/m2(M2)、3.6 kg/m2(M3),羊板粪与颗粒有机肥两两组合共16个处理。分析不同配施处理下试验小区土壤理化性质和土壤酶活性,研究结果表明：(1)M3S2处理下平地土壤最大持水量、毛管持水量、毛管孔隙度分别是M0S0处理(对照)的3.9、4.1和1.8倍,土壤容重相比M0S0处理降低42.8%;M3S2处理...  相似文献   

9.
为了研究不同尺寸传感器的检测灵敏度,该文以磁致伸缩膜片为物理传感器,多克隆抗体为生物识别元件,采用Langmuir-Blodgett(LB)技术将多克隆抗体固定在磁致伸缩膜片表面,制备了用于检测沙门氏菌的磁致伸缩生物传感器。检测时,将不同尺寸的生物传感器浸在含有沙门氏菌的被测溶液里,由于生物传感器对沙门氏菌的吸附使传感器质量增加,从而使传感器共振频率发生改变。采用尺寸为2 mm×0.4 mm×15μm,5 mm×1 mm×15μm和25 mm×5 mm×15μm的传感器检测浓度为102~109 CFU/m L的沙门氏菌溶液,并利用扫描电子显微镜观察传感器表面。研究结果表明,由传感器共振频率变化计算获得的沙门氏菌浓度与扫描电子显微镜观察统计分析获得的直观浓度吻合得很好,两者最大相对差值小于10%。传感器尺寸越小,检测灵敏度越高。尺寸为2 mm×0.4 mm×15μm,5 mm×1 mm×15μm和25 mm×5 mm×15μm的检测极限分别为5×103 CFU/m L,105 CFU/m L和107 CFU/m L。研究结果可为磁致伸缩生物传感器实际应用时,根据预测的细菌浓度,在保证灵敏度的前提下选择合适尺寸的传感器提供参考。  相似文献   

10.
以锡林郭勒草原乌兰图嘎煤矿排土场为主要研究对象,通过对生物笆与沙障2种不同治理措施下的土壤状况（温度、湿度、有机质、pH值）和植被状况（种类组成、密度、盖度）的测定与分析,对其植被恢复效果进行了评价。初步分析表明,生物笆区的表土温度比沙障区低2～5℃,生物笆具有遮阴性;生物笆区的表土湿度比沙障区增加0.60%～1%,生物笆具有增湿性。在措施实施5 a后,生物笆区的表土有机质比沙障区增加了2～5.80 g/kg。在整个植物群落中,多年生草本所占植物种类总数的比例,生物笆区比沙障区多13.84%;生物笆区以多年生植物的重要值较大并占有绝对优势,沙障区以一年生植物占优势;生物笆区的植被平均密度比沙障区多2.60株/m2,盖度大18.50%。在锡林郭勒草原矿区目前常用的生物笆（单网格20 cm×20 cm）治理措施比沙障（行距30 cm,株距10 cm）更有利于植被恢复。  相似文献   

11.
【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。  相似文献   

12.
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.  相似文献   

13.
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,  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg−1 buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg−1 in conditioned and control soil, respectively. The results demonstrate that BioSep® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.  相似文献   

19.
Arbitrary oligonucleotides were used as primers to amplifygenomic DNA of 48 wild Spanish populations of Agropyroncristatum, Elymus hispanicus,E. caninus,E. repens,Thinopyrum curvifolium, Th.junceum and Th.intermedium. Genetic diversity was analysedusing nineteen primers. The number of amplified products ranged from8 to 18 per primer and a total of 240 markers were scored. Differentlevels of intraspecific genetic diversity were found, the allogamousspecies E. repens andTh. intermedium being themost variable. Jaccard's similarity coefficients for internalmeasure within and between populations were used to produce a clusterdiagram. The results demonstrate differences in the degree ofsimilarity between taxonomic units. Interpopulational variability andinterspecific genomic relationships of these species arediscussed.  相似文献   

20.
The effects of three commonly used fungicides on the colonization and sporulation by a mixture of three arbuscular mycorrhizal (AM) fungi consisting of Glomus etunicatum (Becker & Gerd.), Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, and Gigaspora rosea (Nicol. & Schenck) in symbiosis with pea plants and the resulting response of the host-plant were examined. Benomyl, PCNB, and captan were applied as soil drenches at a rate of 20 mg active ingredient kg-1 soil 2 weeks after transplanting pea seedlings in a silty clay-loam soil containing the mixed inocula of AM fungi (AM plants). Effects of fungicides were compared to untreated plants that were inoculated with fungi (AM control). The effect of mycorrhizal inoculation on plant growth was also examined by including nonmycorrhizal, non-fungicide-treated plants (non-AM control). Fungicides or inoculation with AM fungi had only a small effect on the final shoot weights of pea plants, but had greater effects on root length and seed yield. AM control plants had higher seed yields and lower root lengths than the corresponding non-AM plants, and the fungicide-treated AM plants had intermediate yields and root lengths. Seed N and P contents were likewise highest in AM control plants, lowest in non-AM plants, and intermediate in fungicide-treated AM plants. All three fungicides depressed the proportion (%) of root length colonized by AM fungi, but these differences did not translate to reductions in the total root length that was colonized, since roots were longer in the fungicide-treated AM plants. Pea plants apparently compensated for the reduction in AM-fungal metabolism due to fungicides by increasing root growth. Fungicides affected the population of the three fungi as determined by sporulation at the final harvest. Captan significantly reduced the number, relative abundance, and relative volume of G. rosea spores in the final population relative to the controls. The relative volume of G. etunicatum spores was greater in all the fungicide-treated soils, while G. mosseae relative volumes were only greater in the captan-treated soil. These findings show that fungicides can alter the species composition of an AM-fungal community. The results also show that AM fungi can increase seed yield without enhancing the vegetative shoot growth of host plants.  相似文献   

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