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1.
基于电阻率断层扫描技术的土壤砾石体积含量评估 总被引：5，自引：1，他引：4
为了对电阻率断层扫描技术应用于土壤中砾石含量的研究进行评估,该文对此应用进行了数值模拟研究。该研究假设石质土壤为由细土和砾石组成的二相介质,采用有线差分法对所建立土壤数值模型进行了电阻率断层扫描模拟,模型中砾石随机分布且相互独立,过程中对砾石尺寸和土壤中水分情况的影响进行了研究。结果表明对已知二相各自电阻率值的石质土壤,其等效电阻率与其中砾石体积含量相关,数值模拟结果与理论预测结果相符合,验证了电阻率断层扫描技术应用土壤中砾石体积含量估计的可适用性,同时指出在土壤较湿润时为该技术的适宜使用条件。该研究为土壤学分类研究及质量评价提供参考和指导。 相似文献
2.
土壤砾石含量的电阻率断层扫描技术应用研究 总被引：3，自引：1，他引：2
砾石含量是土壤质量评价与分类的基本参量。但传统的测定采用了随机采样的方法,一些特殊和极端区域的土样难以获得,进而制约了对土壤砾石含量评价的客观性和完整性。本研究基于土壤由细土和砾石二相介质组成的假设,采用了电阻率断层扫描技术,结合该技术对土壤中砾石体积含量的评价,对土壤砾石含量做了系统性研究。结果表明细土样品的电阻率值主要受土壤含水量的影响,容重及有机质含量对其影响较小。土壤砾石体积含量和有效电阻率之间的关系与Bussian's Law模型预测结果相吻合,且细土电阻率值对该关系影响较大。在细土和砾石的电阻率值分别为160Ωm和3000Ωm条件下,对砾石体积含量估算结果的绝对误差为22%。电阻率断层扫描技术提供了土壤学基础研究的重要工具,对其应用的研究将会对土壤学相关研究提供重要的帮助。 相似文献
3.
基于模糊集理论提取土壤—地形定量关系及制图应用 总被引：8，自引：1，他引：8
通过对研究区地形因子的模糊聚类,提取了地形因子组合与特定土壤属性的定量隶属度关系,然后对隶属度高值区土壤进行目的性采样为隶属度函数赋值,制作研究区土层厚度连续分布图。通过野外实地验证,将观测值与图中预测值比较,结果显示该方法制图精度在82%左右,具有一定的可靠性。进一步考察认为该模型在地形部位较低,地势较为平坦,土壤发育较好,土层较厚,成土环境相对稳定的地区预测效果更好,适用性更强。该方法能提高土壤制图效率,降低制图成本,提高制图精度,对土壤微域变异的表现更为详细,图面信息负载量更高。应用该方法制作大比例尺土壤详图不失为土壤调查与制图领域一种可行的新方法。 相似文献
4.
喀斯特地区不同土地利用类型土壤侵蚀特征研究 总被引：8，自引：2，他引：6
探明喀斯特土壤侵蚀特征,对石漠化过程研究具有重要意义.采用野外调查与室内试验相结合的方法,通过样品分析、直剪试验与模拟冲刷试验,研究了典型喀斯特地区不同地类的土壤侵蚀特征.结果表明:(1)该地区灌丛地土层厚度大于林地和坡耕地的土层厚度;(2)该区土壤紧实度由小到大的顺序为:坡耕地<灌丛地<林地;(3)在土壤崩解速率及土壤冲刷模数方面,坡耕地＞灌丛地＞林地.整体上,坡耕地土壤侵蚀特征表现出极强的差异性,灌丛地与林地间差异性不显著.因而保持与恢复喀斯特地区植被、减少耕作活动是防治土壤侵蚀和控制石漠化的主要途径. 相似文献
5.
不同土地利用方式下渭-库绿洲土壤质量评价 总被引：3，自引：0，他引：3
[目的]定量评价渭干河—库车三角州绿洲(简称渭—库绿州)不同土地利用方式下的土壤质量,为该区域土地资源的合理利用与规划以及土壤质量的管理与治理服务。[方法]基于渭—库绿洲实地采样数据,利用土壤质量评价指标,采用土壤质量指数(SQI)综合评价法,在ArcGIS 9.3软件支持下对研究区土壤质量的空间分布状况进行定量评价。[结果]不同土地利用方式下的土壤质量指数的平均水平存在显著差异(p0.05),其土壤质量由高到低的顺序依次为:林地耕地荒漠灌丛盐碱草地,其中林地的平均土壤质量指数为0.48,盐碱草地的平均土壤质量指数为0.24。[结论]从空间分布上,渭—库绿洲的土壤质量总体处于中低水平,只有研究区中部区域具有较高水平的土壤质量。不同土地利用方式下土壤质量差异明显。 相似文献
6.
黄土高原沟壑区小流域不同植被覆被对土壤性质的影响 总被引：3，自引：0，他引：3
为揭示不同植被覆盖对土壤性质的影响,运用野外调查和室内分析的方法对南小河沟流域不同植被覆盖土壤13种基本性质及土壤质量进行研究,结果发现:草地土壤物理结构在三种植被恢复土壤中为最佳。不同植被恢复土壤养分含量在剖面中均具有不等的表聚性,土壤有机质、全氮、矿质氮、速效钾和CEC在剖面中均表现为随土层加深而降低,pH随土层加深而增加,而全磷则无太大规律。在相同土层,不同植被恢复土壤表现不一。51 a的油松林地0-105 cm土层土壤质量均有明显提高,51 a的刺槐林地0-45 cm土层土壤质量有所改善,而45-105 cm土层土壤质量则有所退化。 相似文献
7.
8.
西南特大干旱条件下贵州西部山地土壤含水量变化研究 总被引：2，自引：1，他引：1
2010年我国西南特大干旱对区域内生态环境形成严重干扰,地表植被受到严峻的考验。选取本次受灾最严重的区域之一——贵州盘县为研究区域,对乔木林地、灌木林地和耕地自然坡面不同坡位的0—60 cm土壤分层采样,分析特大干旱干扰下区域土壤含水量及其变化规律,旨在为该区域干旱灾害的防灾减灾及相关研究提供参考。分析结果表明:1从土壤表层向下到60 cm深度,不同地表覆被、不同坡位的土壤含水量均呈逐渐增大的变化趋势,土壤含水量与土层深度呈线性相关关系。2不同地表覆被类型的土壤含水量差异表现为乔木林地>灌木林地>耕地,乔木林地与灌木林地相应土层土壤含水量差值在3.556.30百分点之间,灌木林地与耕地差值在5.246.30百分点之间,灌木林地与耕地差值在5.2416.77百分点,乔木林地与耕地差值在11.1916.77百分点,乔木林地与耕地差值在11.1921.08百分点。3乔木林地的下坡与中上坡相应土层的土壤含水量差异较大,灌木林地和耕地不同坡位相应土层的土壤含水量差异不大,土层厚度对不同坡位土壤含水量的影响较大。 相似文献
9.
土壤层次的精确划分关系到土壤学相关研究结果的精确程度。为对田间尺度上层状土壤进行无损精细分层,采用电阻率成像技术,同时结合电阻率曲线纵向上的变化特征精细划分土壤层次,并将精细分层结果应用于层状土壤电阻率空间变异性研究。结果表明:运用电阻率曲线法对反演电阻率数据进行精细划分后,形成结果图能很好的满足研究过程中可视化呈现及精细化表达等需要;根据温纳四极反演电阻率曲线法将研究区内的剖面浅层土壤划分为5—13,13—24,24—50,50—70cm 4个层次;5—13cm(耕作层)电阻率值的变异系数最高(0.28),13—24cm(犁底层)平均电阻率值最低(17.35Ω·m)。研究成果可为土壤水文学和精准农业等相关研究提供技术支撑。 相似文献
10.
以江苏省靖江市牧城公园和东湖公园两种种植年限分别为5 a和9 a的中山杉(Taxodium hybrid'Zhongshanshan')人工林土壤和无林地为研究对象,对0~15 cm、15~30 cm和30~45 cm深度土层土壤理化性质、养分含量和微生物生物量进行了分析。典型相关分析表明,土壤微生物生物量的变化是一个复杂的过程,是土壤各因子共同作用的结果,3种土壤U、V值均表现出层次性,随着土壤深度的增加逐渐降低;不同取样点相同深度土层U、V值为9 a林5 a林对照;单相关分析表明,土壤微生物生物量与速效磷、速效钾、有机质和全氮呈极显著正相关(P0.01),因此土壤微生物可以作为评价中山杉人工林在促进林地土壤质量改善过程中的重要生物指标;主成分分析表明,综合得分最高的9 a林为2.993,其次是5 a林为0.748,作为对照的无林地则为-3.742,说明9 a林地土壤质量最高。可见,中山杉对林下土壤质量有显著提高作用。 相似文献
11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响 总被引：2，自引：2，他引：0
【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.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
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. 相似文献
13.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
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
14.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
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. 相似文献
15.
《中国生态农业学报》2014,(6)
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
16.
《中国生态农业学报》2014,(7)
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
17.
《中国生态农业学报》2014,(8)
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
18.
I.L. Boyd 《Biological conservation》2010,143(7):1664-1674
“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. 相似文献
19.
Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage 总被引：1，自引：0，他引：1
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. 相似文献
20.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
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