西南黄壤坡耕地保护性耕作的土壤结构效应

设置两种保护性耕作措施,通过6a持续试验,研究了保护性耕作措施对黄壤结构性状的影响,为西南黄壤地区保护性耕作技术应用与发展提供理论依据。[方法]分别用环刀法、干湿筛法测定土壤容重和土壤团聚体组成,土壤机械组成采用MS2000激光粒度分析仪测定,并计算出土壤孔隙度和团聚体破坏率。 [结果]结果表明：(1)垄播沟覆轮耕与免耕秸秆覆盖两种保护性耕作措施均可降低黄壤容重,增加土壤孔隙,且此作用是由表及里的渐进过程,垄播沟覆措施的土壤容重优化作用要优于免耕覆盖,而免耕覆盖对较深层次土壤孔隙状况优化效果更显著。(2)保护性耕作可提高0～20 cm土壤＞0.25mm干筛团聚体含量,水稳性团聚体含量处理之间差异不显著,但0～20cm层含量略大于20～40cm层。(3)保护性耕作可提高土壤团聚体稳定性,降低团聚体破坏率,免耕覆盖措施对提高土壤团聚体稳定性具有更加显著的效果。[结论]该试验证明了保护性耕作对黄壤土容重、孔隙、团聚体等结构性状有一定的改善作用,这种改善作用是一个非常漫长的由表及里的渐进过程,为西南黄壤地区保护性耕作技术应用与发展奠定了坚实的基础。     

黑龙江省黑土地保护性耕作实施基本情况及问题研究

黑土有机质含量丰富,土壤养分高,是全球最优质的土壤资源之一,更是国家的宝贵战略资源。黑龙江省地处中国东北部,黑土区土壤肥沃,是国家重要的商品粮基地。但是近年来由于水土流失等原因造成黑土肥力下降、黑土层变薄等相关问题,需要全面推行黑土地保护性耕作方法。运用数据分析法,参考文献法等方法,对黑龙江省黑土地保护性耕作实施的基本情况及问题进行分析。在黑土地保护性耕作实施过程中,面临着农户对黑土地保护耕作方式认知程度偏低、技术运用不规范、技术种类和机具数量偏少、缺少黑土地保护性耕作长效机制等现实问题。因此,提议从提高农户认知程度、建立大面积黑土地保护性耕作示范基地、提升政府扶持力度、为黑土地保护性耕作技术研发和装备供给提供专项资金、建立黑土地保护性耕作长效机制等方面建设黑土地保护性耕作的发展之路。     

根系对土壤环境胁迫响应的研究进展

根系是土壤和植物的动态界面,植物根系具有锚定植株、吸收和运输土壤中的水分及养分、合成和贮藏营养物质等重要功能。近年来,随着研究方法的改进和现代根系定量分析技术的发展,对根系的研究日益受到重视和关注。因而,根系的研究在多个新的研究方向上展开。本文简要介绍了国内外近年来在根系对土壤环境胁迫响应的研究进展,以供根系研究参考。     

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。     

Influence of Soft Soil Layer on Dynamic Characteristic of the Slope

The dynamic finite element method is used to analyzes the influence on dynamic characteristic of the slope by soft soil layer. The parameters which influencing the earthquake response of the slope, including the depth, the thickness, the obliquity of soft soil layer are analyzed. The influence of soft soil layer is obvious, which must be thought over in the analysis of slope stability. The thicker the soft soil layer is, the more obvious the filter and the amplitude effect is. The deeper the soft soil layer is, the more obvious the filter effect is. The filter effect of the obliquity of the soft soil layer to dynamic time history is not obvious.     

烟-稻复种连作对红壤性水稻土团聚体组成及稳定性的影响

红壤性水稻土面临土壤结构退化、土壤养分失衡和酸化等土壤质量问题,制约农业生产和农民增收。本文以南方红壤丘陵区植烟的红壤性水稻土为对象,采用时空替代法、相关及冗余分析等技术方法,研究了烟-稻复种连作(YDLZ)对红壤性水稻土团聚体及其稳定性变化的影响及其关键影响因素。YDLZ后的红壤性水稻土>5 mm团聚体含量、土壤团聚体重量平均直径(MWD)和几何平均直径(GMD)均显著降低,<0.25 mm团聚体含量和分形维数(D)则显著升高,土壤团聚体稳定性降低;且以YDLZ 5～10年(YDLZ5～10)对土壤团聚体粒径分布及稳定性影响最大。相关及冗余分析表明,土壤有机质和粘粒含量是引起团聚体分布的关键指标;>5 mm和<0.25 mm的团聚体含量是引起团聚体稳定性变化的关键指标。烟-稻复种连作引起红壤性水稻土有机质和粘粒含量变化,主要导致>5 mm团聚体含量的减少,<0.25 mm团聚体含量增加,从而土壤团聚体稳定性降低。针对YDLZ的红壤性水稻土结构培育和土壤质量保育,需关注土壤有机质及粘粒含量的变化。     

FEM on Coupled Hydromechanical Dynamic Response of Geogrid Reinforced Soil Retaining Wall

Geogrid reinforced soil retaining wall(GRSRW) is composed of panel,geogrid and soil,its coupled hydromechanical structural characteristics are increasingly emphasized in practice.In this paper,based on the characteristics of the reinforcement-soil interaction,the grogrid and soil around it with a definite thickness were regarded as a kind of composite material with strain-compatible condition.A saturated porous media model was introduced to simulate the soil and reinforcement-soil composite material hereby and the mathematic model for numerical analysis on structural characteristics of GRSRW was built up.The FEM equations were deduced from the standard Galerkin procedure,resolving these equations,we can gain the relevant dynamic response of saturated GRSRW.     

凋落物分解对森林土壤碳库影响的研究进展

凋落物分解是陆地生态系统物质循环和能量转换的主要途径,是森林生态系统重要功能之一。凋落物作为外源有机物质,进入土壤后其分解不但会增加土壤中碳源,改变土壤理化性质,而且还会增加土壤中各种微生物的数量,改变土壤微生物群落结构,加速土壤有机碳矿化速率,从而对土壤有机碳库动态变化产生重要影响。土壤是陆地生态系统的核心,研究土壤碳库动态对正确评价土壤在陆地生态系统碳循环以及全球变化中的作用有重要意义。本文就凋落物分解过程及对土壤碳库中土壤呼吸、土壤有机碳、土壤微生物量碳、土壤碳矿化及理化性质等影响进行综述,为土壤碳库周转动态研究提供参考。     

不同种植年限对菜地土壤结构的影响

为了探究不同种植年限对菜地土壤结构的影响情况,为土壤培肥提出切实可行的方法,采用萨维诺夫法分析了重庆市九龙坡区白市驿镇蔬菜基地种植1年、5年、10年的菜地土壤团聚体的组成情况及其差异。结果表明：水稳性团聚体含量以及稳定性在不同种植年限土壤间存在较大差异。对于0~20 cm土层土壤,1~0.25 mm、>3 mm和>5 mm水稳性团聚体含量均表现为1年>5年>10年,20~40 cm土层也存在类似变化。表明随着种植年限的增加,各土层土壤水稳性团聚体含量逐渐降低。对于0~20 cm土层,1年土壤>0.25 mm团聚体平均破坏率为27.78%,5年和10年土壤>0.25 mm团聚体平均破坏率分别高达49.86%、58.74%;对于各种植年限土壤20~40 cm土层也存在相同的趋势。说明随着种植年限的增加,土壤团聚体破坏率增高,土壤结构稳定性降低。相关分析表明,土壤有机质含量与种植年限、平均破坏率呈显著负相关（相关系数分别为-0.880*、-0.897*、n=6）,与>0.25 mm水稳性团聚体含量、>3 mm水稳性团聚体含量、>5 mm水稳性团聚体含量、3~1 mm水稳性团聚体含量、1~0.25 mm水稳性团聚体含量呈显著正相关（相关系数分别为0.897*、0.868*、0.859*、0.835*、0.829*、n=6）,土壤团聚体MWD与>0.25 mm水稳性团聚体含量之间达到极显著正相关（相关系数为0.985**,n=6）。说明随着种植年限增加,土壤有机质含量降低,水稳性团聚体含量增加,平均破坏率逐渐增加。>0.25 mm的水稳性团聚体含量越多,土壤平均重量直径(MWD)值越大,土壤团聚体稳定性越强。有机质含量是影响研究区紫色土土壤水稳性团聚体含量及稳定性的主要因素。     

Seismic Behavior of a Slope Protected by a Soil Nailing Retaining Wall during an Earthquake

The dynamic elastic plastic finite element method was used to study the seismic performance of a slope protected by a soil nailing retaining wall. On the basis of working in parallel and interaction between loess and a flexible retaining wall, a 3 D nonlinear finite element method (ADINA) also was established. Rational earthquake excitation and damping were discussed for geological engineering. Horizontal and vertical excitations were considered simultaneously in the analyses. A model capable of simulating the nonlinear static and dynamic elastic plastic behavior of soil was used to model the soil, and a bilinear elastic plastic model having hardening behavior was used to model the soil nailing. A friction element was employed to describe the soil structure interaction behavior. Our research focused on the seismic performance of the horizontal and vertical slope deformation, soil nailing axial force, and earth pressure subjected to horizontal and vertical excitations. The results show that the seismic performance of slope protected by soil nailing is good; soil nailing axial force increases after an earthquake; permanent slope displacement occurs during an earthquake; and the peak earth pressure distribution during an earthquake is similar to the earth pressure before the earthquake. These conclusions can provide references for seismic analyses and design in soil nailing engineering.     

Application of Improved Multi-population Genetic Algorithm to Damage Identification of Soil-wall System

The method of damage identification in soil-wall system was studied; a new approach based on improved multi-population genetic algorithm (IMGA) was developed. First, the simplified dynamic-detection model of soil-wall system was established, meanwhile, the theoretical analysis of characteristic equations in soil-wall system was conducted when soil in damage status. The objective function based on characteristic equations was established. Then, the improvements of multi-population genetic algorithm, including the adoption of real-valued representation, adaptive cross operator and adaptive mutation operator, were conducted. Finally, the localization and quantification of the soil-wall system damage were performed by IMGA with and without the consideration of noise, respectively. The results indicate that damage location and damage extent can be detected efficiently, and anti-noise performance is better.     

南疆膜下滴灌棉田土壤酶活性与土壤养分的关系

探讨土壤酶活性与土壤肥力质量指标的相关性,为棉田土壤质量评价提供生物学指标。以南疆棉田土壤为研究对象,测定棉田土壤养分含量和土壤酶活性,采用相关分析、通径分析和主成分等统计方法进行分析。土壤过氧化氢酶、酸性转化酶、碱性磷酸酶、脲酶与土壤有机质、全氮、速效磷达到极显著相关关系;通径分析表明,全氮和有机质含量是影响土壤酶活性的主要因子;有机质、全氮、过氧化氢酶、碱性磷酸酶是反映土壤肥力和质量的主要组分。用过氧化氢酶、酸性转化酶、碱性磷酸酶作为评价棉田土壤肥力水平的敏感生物指标具有可行性。     

土壤多糖的研究进展

土壤多糖是土壤中碳水化合物的主要存在形式,是土壤中一种重要的有机胶结物质,国内外对土壤多糖的研究涉及众多方面。从土壤多糖的来源、组成、含量及分布,土壤多糖的化学结构,土壤多糖的稳定性,土壤多糖对土壤结构形成的作用以及对土壤肥力的意义等方面进行了梳理和总结,为土壤多糖的深入研究提供借鉴。     

吉林东部暗棕壤在中国土壤系统分类中的归属

为了研究吉林东部暗棕壤在中国土壤系统分类中的归属,采用当前国际土壤分类的主流的土壤系统分类法,以吉林省东部暗棕壤的5个典型剖面为研究对象,通过野外剖面形态特征调查、剖面描述、理化性质分析,研究了土壤的发生特性,确定土体的诊断层与诊断特征,按照《中国土壤系统分类检索（第3版）》的标准,初步确定吉林东部暗棕壤在中国土壤系统分类中归为淋溶土和雏形土2个土纲,冷凉淋溶土和湿润雏形土2个亚纲。     

区域水土保持水土流失预测分析及实例研究

水利部对各类开发区提出推行区域水土保持评估的背景下,分析水土流失量预测方法及技术要点。以庆安开发区为例,分析东北黑土区水土流失量预测及土石方平衡估算,可以为同类区域水土保持评估水土流失量计算提供借鉴及参考。通过计算分析,得到2条结论:（1）在考虑最不利条件下,预测区域内土壤流失量结果中工业用地新增土壤流失量最大;（2）对于规划建设及在建区域,可以采用区域内已完成水土保持方案的已建项目为典型项目,类比推算区域土石方挖填量的方法。     

长期不同耕作对白浆土磷素状况的影响

国内外对磷素的长期试验大多定位在施肥上,而耕作对其影响的研究很少,为探明耕作对土壤磷素状况的影响,本文对长期定位16年的白浆土进行了研究,试验结果表明研究表明不同耕作方式对土壤全磷、有效磷的影响远远小于施肥,免耕较深松、常规耕作更有利于土壤全磷的积累,但不利于有效磷的增加,其磷组分除LOP含量减少外,其余磷组分均增加。深松与常规耕作处理土壤磷组分除Ca2-P外,其他磷组分的变化趋势相同。因此我们在改善土壤磷素状况方面除了采用施肥措施外,还可以考虑采用不同的耕作方式来调节土壤磷素营养。     

新型自动土壤水分传感器与传统FDR法传感器性能对比分析

本文在传统FDR法自动土壤水分传感器基础上,通过重新设计测量电路,开发了一种新型自动土壤水分传感器,并在实验室内开展了新型传感器电气性能、测量性能、抗温度变化特性、抗盐碱性能等传感器特性与传统FDR法自动土壤水分传感器的对比分析或试验。通过对比分析或试验,结果表明：新型自动土壤水分传感器可以实现土壤水分的连续监测,满足传感器的测量性能需求;新型自动土壤水分传感器与传统FDR法自动土壤水分传感器相比,标定过程相对简单、测量精度及测量准确性更高、抗干扰性更强、稳定性更高。新型自动土壤水分传感器的研发设计,提高了土壤水分监测的准确性、稳定性,为自动土壤水分观测仪的升级换代提供了技术支撑。     

Longitudinal Vibrations of a Single Pile in Saturated Viscoelastic Soil

Based on Biot's theory, the longitudinal vibrations of a single pile in saturated viscoelastic soil are investigated in the frequency domain subject to the harmonic load. By the Novak plane strain model, the control equations for the saturated viscoelastic soil are derived. Regarding the pile as the one-dimensional rod model, the vibration equation of the pile is established. Based on the continuity conditions of the pile and soil, the dynamic stiffness and dynamic damping of the pile top are obtained. It is compared with the solution for Novak, and the influence of different physical parameters of the pile and soil on the longitudinal vibrations of the soil and pile system is examined. It is shown that the dynamic characteristics of the pile in the dry soil as well as the saturated soil have some differences; the resonance effect of dynamic stiffness factor and equivalent damping is obvious weakening with the increase of the ratio of the length to radius of the pile. The resonance effect and natural frequency are increasing when the modulus ratio of the pile to soil increases; the interaction coefficient of the flow-solid and the damping ratio of soil skeleton have few influences on the responses.     

The Ecological Value and Feasibility of Composting Technology for Garden Soil Improvement

Soil quality of garden plants is an important factor for good growth of garden plants.Based on the analysis of the current situation of garden soil,the ecological value and feasibility of composting technology applied in garden soil improvement were discussed.This study provided a basis for strengthening the quality management of garden soil,improving the standard of garden soil improvement,and helping the healthy and sustainable development of modern garden greening.     

Issues and Some Strategies of Sustainable Development of Black Soil Resources in Black Soil Zone in Northeast China

黑土资源是世界的稀缺资源，黑土带的水土流失、环境污染、土地流转、土地退化问题成为黑土资源可持续发展的障碍。根据实地调研结合资料，分析了东北黑土带土地资源可持续发展的主要问题; 提出了黑土资源的可持续发展对策,即：加强农业发展规划;保护黑土区耕地,农耕技术上改进，加强农田基本建设等。