湘西州植烟土壤有机质特征及与土壤养分的相关性研究

为深入了解湘西植烟土壤有机质含量区域特征,对湘西州488个烤烟主产区植烟土壤样品进行化验分析研究。结果表明:湘西州植烟土壤有机质总体上属适宜水平,平均值为2.2%,变幅为0.3%~5.4%,变异系数为39.9%,41.5%样本有机质处于适宜范围内,"缺乏"和"偏低"的植烟土壤样本共占43.5%,"丰富"和"偏高"的植烟土壤样本之和为15.0%,不同植烟土壤类型的有机质含量差异达极显著水平(P=0.000),水稻土黄棕壤黄壤红壤石灰土红灰土,总的来说,从东北部、西部和西南部向州中部及东南方向有机质减少。方差分析结果表明,有随海拔高度的升高而有机质含量增高的趋势,植烟土壤有机质与海拔为显著正相关(P=0.012),土壤有机质含量与全氮、全磷、有效硼的含量呈极显著相关(P值分别为0.0000、0.0098、0.0029),与有效硫、交换性镁、交换性钙含量呈显著相关(P值分别为0.036、0.019、0.042)。     

地膜覆盖下土壤有机质的分解与积累

还田有机物在地膜覆盖下的分解略高于露地栽培,腐殖化系数为0.17～0.41,土壤有机质的年亩矿化量为92～164kg.有机无机肥配施,对土壤有机质的贡献高于不施肥、单施化肥和单施有机肥,尤其是未经分解的有机物,适量配施化肥,明显优于等氮量的腐熟有机肥.为此,要重新组合农业措施.以调整土壤有机质分解与积累之间的关系.     

化肥与有机物料配施对作物产量及土壤有机质的影响

通过对北京褐潮土土壤肥力和肥料效益监测基地10年定位微区试验的调查分析表明：在土壤肥力水平较低的情况下施用氮、磷、钾化肥及氮磷钾化肥与有机物料配施，具有显著提高粮食产量的作用，并较大幅度提高土壤有机质含量；随着有机物料施用量的增加，效果更为明显。有机物料效果以有机肥最佳，其次为小麦秸秆，玉米秸秆与化肥配施效果与单一施化肥相近。     

秸秆还田及施肥对土壤养分的影响

秸秆还田是当今世界普遍重视的一项培肥地力的增产措施,对维持农田肥力,减少化肥使用,提高陆地土壤碳汇能力具有积极作用。合理施肥,能为作物生长创造养分贮量丰富、有效性高、贮供协调的土壤生态环境,同时能提高土壤肥力,增加作物产量,改善农产品质量。介绍了秸秆还田对土壤有机质等养分含量的影响和施肥对土壤养分的影响。     

柠檬酸与土壤磷相互作用的研究进展

为了研究柠檬酸在土壤形成、物质循环等过程中所起的重要作用,笔者综述了国内外近些年来柠檬酸与土壤磷素相互作用的一些研究进展。主要内容包括：（1）柠檬酸的分泌及其分泌机理;（2）缺磷促进分泌柠檬酸分泌状况;（3）柠檬酸对土壤磷吸附的影响;（4）柠檬酸对土壤磷解吸的影响;（5）人工添加柠檬酸减少磷肥投入的效果。在实际生产中柠檬酸对土壤磷素及磷肥的作用研究有待于加强。     

放牧对土壤理化性状及植被多样性的影响

放牧是家畜饲养方式之一,是草地最简单而又有效的利用方式,但放牧中的家畜家禽通过采食牧草、践踏土壤和牧草以及粪便排泄影响着草地植被和土壤,不同强度的放牧对地下土壤与地上植被的影响不同。本研究综述了近几年来放牧对地下部土壤有机质、氮、磷、钾、土壤容重、有机碳以及微生物多样性的影响,对植被多样性及草群成分的影响等,旨在为今后家畜放牧行为研究以及放牧科学研究提供理论依据。     

异构系统中检测蛋白质相互作用方法的原理及应用

基因组测序的完成并没有真正解释出细胞生命活动的本质。科学家们逐渐发现所有细胞功能都涉及蛋白质相互作用,许多疾病的发病也是由于蛋白质相互作用的改变,因此研究蛋白质相互作用具有重要的意义,也成为蛋白质组学研究的重点。目前已有许多实用且成熟的技术应用于蛋白质相互作用的检测。异构系统中检测蛋白质相互作用的方法包括细菌、酵母、哺乳动物细胞的双杂交系统和免疫共沉淀技术。文章将对这些技术的原理及应用作以综述。     

快速测定有机原料中有机质含量的研究

为了快速、准确地测定有机原料中有机质含量,以中华人民共和国农业行业标准NY-2011有机肥料中有机质的测定方法为标准方法,对其中的沸水浴加热氧化条件进行了改进,即恒温烘箱加热氧化法。同时对恒温烘箱加热氧化法测定有机原料中有机质的加热温度、加热时间进行了研究。研究结果表明,与标准方法相比,恒温烘箱100℃加热氧化30 min和175℃加热氧化10 min这2种方法所测的结果准确可靠,而且高效、快捷、更为实用。     

开花期高温胁迫对水稻花粉粒性状及结实率的影响

为探明花期高温胁迫对水稻花器官及结实率的影响。利用人工气候箱在水稻抽穗开花期对特青及其渗入系YIL106进行高温处理,研究结果表明,高温胁迫下热敏感渗入系YIL106的花粉活力、花粉萌发率、柱头上花粉粒数、花药开裂系数和结实率降低幅度均大于耐热品种特青。表明高温胁迫下,水稻的花粉活力、花粉萌发率、柱头上花粉粒数、花药开裂系数、以及结实率都比常温条件下要低,且高温胁迫对热敏感品系的花粉粒性状及结实率影响更大。     

Mechanical Model of Steel Plate Composite Shear Walls

Based on concepts of mechanics, a mechanical model of novel type of steel plate composite shear wall is presented. The novel type of structure is formed by steel plate shear wall and T-shaped solid-web composite columns. Flexural stiffness of steel beams, lateral stiffness of the T-shaped solid-web composite columns, shear stiffness of steel plate composite shear wall and shear stiffness of beam-column connection are taken into account in the mechanical model. And the equivalent damping between steel plate and boundary is considered. Based on the deformation features of structures and the calculation hypothesis, the lateral stiffness model and the energy dissipation model of structures are developed. Meanwhile, the calculation equations of elastic ultimate and plastic ultimate of shear strength of structures are set up. The theoretical analysis results inosculate better with the results of experiment. The comparison between the result calculated from the formula and the experimental result shows that the calculation precision is high enough to meet the demand of theoretical analysis. The difference, including equivalent model, stress states, manufacturing defect and installation error, between the formula and the experiment has been further discussed.     

土壤水分对植物根系固土力学性能的影响综述

为了分析土壤水分对植物根系固土力学性能的影响机制,揭示根系固土力学机理和科学防治土壤流失提供基础理论研究思路,本文分析了土壤含水量对根系分布、根系抗拉特性、根系-土壤相互作用、根系-土壤复合体抗剪特性和根系固土力学模型的影响,探讨了根系固土力学性能对土壤含水量的响应机理研究现状及发展趋势。认为根系形态与根系固土效果紧密相关,目前缺乏土壤水分对根系形态及根系固土力学特性的定量研究;对根系抗拉强度和拔出强度的影响因素等关注较多,但对土壤水分变化是否影响根系强度、根土界面摩擦和根系破坏模式研究非常少;土壤水分在植物固持水土的水文效应中研究较多,但其对根系固土力学性能的影响规律尚需进一步研究;评价根系固土力学性能的模型没有考虑或充分考虑土壤水分变化对固土效果的影响,且模型中各影响因素的相对重要性关系尚不清楚。分析结果深化了对降水影响覆盖植被边坡稳定性机理的理解,为深入研究土壤水分与根系固土力学机制相互作用提供了理论基础。     

Experimental Analysis of the Strength Properties of the Heavy Metal Contaminanted Soil

The samples contaminated by heavy metal were taken from tailing pond and landfill site of wastes The different heavy metal contamination samples with different incorporation ratio are respectively mixed with the undisturbed soil. The content analysis of heavy metal, direct shear test and unconfined compression strength test are carried out in order to study the strength properties of the heavy metal pollution. The results of test and analysis show that: the heavy metal pollution has a very strong impact on the strength properties of soil. With the increase of concentration of heavy metal pollutants i, c-value gradually increased and φ value decreased. Under the same water content, the unconfined compression strength is reduced with the increase of heavy metal content. The strength will decrease by approximately 35%～60%. The characteristics of the diffuse double layer and the thickness of the water film between the soil particles will change when the heavy metal contaminants the soil, the balance relationship between cationic and anionic on the soil surface will also be broken. Therefore, the strength properties of the contaminanted soil will change.     

潮土中小麦最佳施肥模型的建立与应用

依据土中各种养分的供应特征和小麦需肥规律，选择了氮，磷，锰三种元素为试验因素，采用二次正交旋转组合设计试验方法，建立了潮土中小麦最佳施肥模型。结果表明，当氮肥，（纯氮）用量为１２．８５－１６．３５ｋｇ／亩，磷肥（Ｐ２Ｏ５）用量为１１．３６－１４．００ｋｇ／亩，硫酸锰用量为１．１６－１．４９ｋｇ／亩时，小麦边际产量可达３７５ｋｇ／亩。其最佳施肥与最经济施肥量十分接近，此时的投入与产出比为１：５，对小     

小麦播种过程板结疏松装置的研制与应用

为有效解除"旋耕播种镇压一体机"组件镇压辊在滚动过程中与表层土壤挤压形成的"鱼鳞状"板结,提升小麦抗逆节本播种保苗关键技术。通过制定技术方案,在重粘、轻粘及中壤土质的田间试验与示范,研制开发出了由支架、调节构件和疏松构件三部分组成的"小麦播种过程板结疏松装置",经播种期降雨较多年份的试用,可有效破除播种过程板结,为苗全、苗齐、苗壮提供了良好的表土微生境,符合农艺技术要求;该装置具有与"旋耕播种镇压一体机"安装拆卸简捷,生产成本低、作业效率高及机手易操作等特点。该项研究进一步完善了"旋耕播种镇压一体机"的结构与功能,拓宽了土壤适种期,为小麦抗逆节本播种保苗提供了技术支撑。     

基于农作物播种过程板结耧耙装置的研制与应用

为解决作物播种过程板结,有效延伸作物播种时间,缩短出苗时间,提高出苗率,实现合理的群体构建.通过制定技术方案,研制开发出由连接构件、调节构件和耧耙构件组成的"农作物播种过程板结耧耙装置".该装置经在播种期降雨较多年份与已有的"旋耕施肥播种镇压一体机"配套使用,其耧耙构件的耙齿入土深度一致,且符合农艺技术要求,有效解决了...     

Experimental Analysis of the Electro-Osmosis Consolidationof Soft Clay Under Anode Follow-up

Under the equipotential premise gradient, anode follow-up technical was proposed in the electro-osmosis reinforcement of soft clay. Eight electro-osmosis contrast tests were conducted through the experimental test. Currently, shear strength, displacement, moisture content, pH, conductivity of the soil and other indicators were monitored in the electro-osmosis test. Different electro-osmotic reinforcement effects were analyzed. The results show that: when the anode follow-up is used, the first anode follow-up can get a most significant effect. When the current density is high, arranging the anode follow-up will lead some extent reduce of the effect of the electro-osmosis, while the effect will be promoted when the current density is low. By carrying out the anode follow-up on the cathode region soil, a significant reinforcement effect can be obtained. Anode follow-up can reduce the resistance of the circuit in the anode region and effectively promote the electro-osmosis reinforcement effect.     

Experimental Analysis of the Water Weaken Effect on Gravel Soil Roadbed Locating in the Reservoir Region with Different Compactedness

It is vital to get the accurate data of the shear strength parameters of gravel soil with different water content and compactedness before they conduct the stability analysis for gravel soil roadbed. Under several test conditions, a series of direct shear tests were performed by using some gravel soil samples obtained from a selected roadbed which is under the influence of water level fluctuation. The corresponding results show that the gravel soil cohesion increased as the water content of fine soil increases till it meets its peak value, then it will decrease as the water content keeps increase. However, the internal friction angle will decrease slowly with the increase of water content of fine soil in the initial phase, and then it will decrease rapidly as the water content keeps increase. And on the other hand, the fitted shear strength parameters calculated from the test data has been influenced by the pre-load values that used to prepare soil samples, especially for the condition that the pre-load value less than the normal stress value applied in the direct shear test. All in all, the fitted shear parameters will be controlled by the relationship among water content, pre-load value and normal stress.     

Shear Deformation Properties of Sliding Zone Soil and Its Effect on Sliding Mechanism of a Landslide in the Three Gorges Reservoir Area

The mechanical properties of slip soil play a key role in landslide stability. In order to study this control mechanism, multigroup experiments on the slip soil of a landslide were conducted in the Three Gorges reservoir in Zigui county involving consolidated quick direct shear test and consolidated drained direct shear test, through which the strain hardening property of this slip soil has been studiedas well as mechanism of landslide deformation resulting from the strain hardening slip soil. The results show that from plastic deformation to shear failure, the shear stress applied to this slip soil increases all the way. After repeated shearing, its shear strength increases, and the greater the normal stress, the more the shear strength increases, in which process the angle of internal friction contributes the most to its shear strength variation. Through the field investigation and numerical modeling, how the strain hardening slip soil affects the landslide stability was studied. In the process of sliding, the frictional strength of the strain hardening slip soil increases after being shearing, leading to the consumption of the landslide’s kinetic energy, following the phenomenon that a temporary steady state occurs after a short distance sliding.     

农田生态系统中土壤有机碳与团聚体相互作用机制的研究进展

土壤有机碳和土壤结构是衡量土壤地力的重要指标,同时也是影响土壤稳定性和生产力的主要因素之一。土壤有机碳对团聚体的形成和稳定具有重要作用,而土壤团聚结构对土壤有机碳的累积与分解具有显著影响。本文回顾了有机碳影响团聚体形成稳定作用的模式模型;归纳了土壤团聚体对有机碳累积的保护作用机制。在总结土壤有机碳和土壤团聚体相互作用机制的基础上,探讨了农田管理措施对土壤有机碳和团聚体的影响,并概括了目前国际上相关研究的新技术。并在此基础上,提出了在该领域研究中存在的问题,以期为我国土壤地力的持续提升研究提供参考。