三峡库区不同土地利用方式土壤肥力变化——以汝溪河流域为例

以三峡库区汝溪河流域为例,选取了马尾松林地、退耕柏木林地、退耕草地和耕地4种土地利用类型,通过实地采样的方法研究了各个土地利用类型的土壤肥力状况.土壤肥力指标选取了土壤含水量、粒径组成、pH值、有机质,全氮、全磷、全钾、碱解氮、有效磷和速效钾.这些指标在不同土地利用类型间均存在较明显的差异.耕地土壤有机质要显著低于另外3种土地利用类型.养分间的相关分析发现,有机质和全氮、有机质和碱解氮、pH值与全磷、pH值与有效磷、pH值与全钾、全氮与全磷、全钾与全磷、全钾与有效磷间都具有明显的相关性,养分间存在耦合作用.退耕还林还草对提高土壤肥力特别是有机质具有很好的效果.     

喀斯特石漠化区石灰岩与白云岩土壤理化性质分析——以贵州兴义市为例

本文针对兴义市喀斯特石漠化区域内石灰岩和白云岩两种岩石发育的土壤进行理化性质分析比较,结果表明:两种岩石发育的土壤在全磷、交换钙、土壤含水量、石砾含量、土壤容重及岩石裸露率,差异显著。石灰岩区除了全钾与速效钾之外,全氮、全磷、速效氮、速效磷均略优于白云岩区。白云岩区土壤pH与全氮存在负相关关系;有机质含量与全氮、全磷均达到极显著正相关关系,与交换钙达到显著正相关关系;全氮和速效氮存在显著正相关关系。石灰岩区土壤pH与全钾存在负相关关系;有机质含量与全氮达到显著正相关关系,全氮和速效氮为正相关关系。不同坡位的土壤物理特征表明,白云岩区土壤含水量和土壤厚度的平均值自上而下呈现依次递增的变化规律。而其在土壤容重、石砾含量和岩石裸露率的平均值自上而下则呈现依次递减的变化规律。石灰岩区仅在土壤含水量方面自上而下呈现依次递增的变化规律。     

桑园生草对土壤养分、微生物及桑葚品质的影响

以2、4和6a毛叶苕子(Vicia villosa)及自然生草为处理,传统清耕为对照,研究生草对桑园土壤微生物数量、养分含量及果实品质的影响.结果表明:与对照相比,人工种草和自然生草的土壤有机质、全氮、全磷、全钾含量显著提高,其中毛叶苕子6a的土壤有机质、全氮和全钾升幅最高,分别提升了222.6%、132.3%和19.0%,毛叶苕子6a的碱解氮、速效磷和速效钾含量比对照分别提高了46.7%、46.3%和19.2%,而毛叶苕子2a速效磷和速效钾含量低于对照;毛叶苕子6a的细菌、真菌和放线菌数量最多,比对照分别提高了86.8%、151.7%和168.4%;毛叶苕子6a和自然生草6a的可溶性固形物含量分别比对照提高了55.8%和17.0%,还原糖含量分别提高了42.9%和8.5%,总酸含量分别下降了18.7%和14.1%,毛叶苕子能显著提高桑园土壤养分含量和微生物数量,改善桑葚鲜食品质.     

牛粪添加对园林绿化废弃物蚯蚓堆肥的影响研究

采用赤子爱胜蚯蚓(Eisenia fetida)对园林绿化废弃物(GW)进行蚯蚓堆肥,研究牛粪(CD)添加对蚯蚓及堆肥的影响.在保持园林绿化废物占主体的情况下,试验共设5个处理(CD∶GW,干质量):T1(0∶100)、T2(5∶95)、T3(10∶90)、T4(15∶85)和T5(20∶80),进行11周堆肥,测定不同处理下蚯蚓生长繁殖情况和堆肥前后材料的微生物、理化性质变化,并以种子发芽试验测定堆肥效果.结果表明:与T1纯园林废弃物相比,牛粪添加可以提高蚯蚓的存活率、加快蚯蚓生长和繁殖速度;提高纤维素和木质素降解率,增加堆肥产品营养元素含量;增加堆肥产品中细菌、真菌和放线菌数量.各处理发芽指数均达到80%以上,显示堆肥腐熟.在各处理中,T4和T5处理的蚯蚓生长量、繁殖率和产品质量指标显著高于对照T1处理,但T4和T5组间差异不显著,为节约生产成本,基于本试验的环境条件和处理方式,建议牛粪在园林绿化废弃物蚯蚓堆肥按15∶85比例添加.     

南京城市土壤pH和养分的空间分布

采用GIS与地统计学相结合的方法，对南京市城市表层土壤pH、全钾、全磷、速效磷、有机质和全氮的空间分布进行了研究。结果表明，南京市城市土壤pH、全钾的变异函数的理论模型均符合线性有基台模型，可以用克立格（Kriging）插值分析。全磷、速效磷、有机质和全氮经对数处理后，仍然没有合适的拟合模型，采用逆距离加权（IDW）插值进行了分析。土壤pH、全钾有较强的空间相关性，说明它们受成土母质和地形等影响较大，全磷、速效磷、有机质和全氮空间变异性很大，主要受城市人类活动及土地利用方式的影响。     

施用不同肥料对土壤状况的影响

分别测定了天津郭村蔬菜地土样（主要施用农家肥）和小麦地土样（主要施用化学肥料）的pH、含水率、全氮、速效磷、速效钾和有机质的含量以及微生物的数量并进行比较．结果表明,蔬菜地土样除全氮含量比小麦地土样低33．23％外,其余所测指标均比小麦地土样高——含水率高18．46％,速效磷高0．0172g／kg,速效钾高0．054g／kg,有机质高30．89％;蔬菜地中细菌、放线菌、真菌、溶磷细菌和固氮菌的数量都高于小麦地,说明施用不同肥料对土壤的理化性质、微生物数量以及溶磷细菌、固氮菌的数量有很大的影响．     

孝感市水稻土有机质及全量氮磷钾的相关性分析

通过湖北省孝感市安陆、大悟、汉川、孝昌、孝南、应城、云梦的水稻土有机质及全量氮磷钾状况进行的测定分析表明:各地有机质及全量氮磷钾间的含量差异颇大,总体表现为全钾含量较高,其他元素含量中等.全钾含量除应城外,均高于世界土壤的平均水平;全磷含量差异较大,表现为孝南较大,云梦较低;全市水稻土中有机质及全量氮磷钾含量间的相关性均未达到显著水平,仅全磷与有机质、全氮和全钾呈负相关.     

基于SQI的岷江上游干旱河谷肥力空间分异特征

选择岷江上游干旱河谷杂谷脑河流域为典型研究区域,通过调查取样、理化分析和模型计算,定量分析该区土壤肥力的空间变异特征。结果表明:土壤有机质、有效磷、全钾和有效钾的含量沿河呈现先升高后略下降的趋势;全氮、有效氮和pH值缓慢增大;全磷呈现上下波动状态。土壤有机质、全氮、有效氮和全钾含量随着海拔升高而增大;全磷、有效磷和有效钾含量随着海拔升高而先增大后降低;pH值略有降低。岷江上游干旱河谷高半山区域(2 000 m以上)土壤保持了较高水平的土壤质量,而杂谷脑河下游土壤质量优于上游。     

EM菌和蚯蚓对污染土壤元素转化的作用

将蚯蚓接种至不同Effective Microorganisms（EM菌）添加量的污染土壤中, 28 d后对蚯蚓体质量、 产茧量以及土壤中的有机质、 氮和磷的质量比进行对比, 考察EM菌对蚯蚓在污染土壤中活动的影响及对土壤元素转化的作用. 结果表明： 将蚯蚓接种到污染土壤后, 其体质量减轻, 日增质量倍数为负值; 添加EM菌的污染土壤中蚯蚓的体质量减少量、 日增质量倍数和产茧量低于未加EM菌的对照组; 添加不同EM菌的土壤中有机质、 全氮、 全磷的质量比以及pH值低于未添加EM菌仅蚯蚓作用的土壤; 土壤中的铵态氮、 硝态氮和速效磷质量比的变化规律相反.     

巨菌草对土壤生态环境的影响

为评估巨菌草(Pennisetum Giganteum z.x.Lin)对土壤生态环境的影响,收集了黄河上中下游不同地区巨菌草和裸地(对照)的土壤样品,系统分析了巨菌草生长1 a后对土壤肥力、微生物和酶活性的影响,并定量分析了巨菌草对土壤性质的改善程度。结果表明,巨菌草具有降低土壤pH值和全钾、增加有机质、全氮、全磷、细菌、真菌、放线菌、过氧化氢酶、多酚氧化酶和脲酶等的作用;消除裸地(对照)的影响,巨菌草对土壤pH值和全钾的降低幅度分别为3.5%和4.6%,对有机质、全氮、真菌、放线菌、多酚氧化酶和脲酶的增加幅度均超过100%,表明巨菌草具有改善土壤生态环境的作用。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the