ABC分类方法在土壤实验室仪器管理中的应用研究

实验仪器是实验室的核心部分,其管理水平关系着实践教学的质量。文章在分析ABC分类方法核心原理的基础上,结合广西生态工程职业技术学院土壤实验室仪器管理经验,运用ABC分类方法,把仪器分成A、B、C 3类,并根据分类结果分别采取不同的分类管理策略,规范了仪器管理,提高了仪器管理效率。

自己动手建设生物-土壤实验室

就该实验室建设过程中的一些经验和教训作了总结 ,并提出了一些建议。

高校土壤学实验室安全现状分析与管理对策

实验教学在土壤学教学工作中发挥着重要作用,随着高等农林院校的迅速发展,土壤学课程不断增加,给土壤学实验室安全管理带来了巨大的挑战。以山东农业大学土壤学实验室为例,针对土壤学实验室安全管理和实验教学过程中存在的安全隐患源和主要问题,提出了通过健全实验室安全管理体制、加强师生安全教育和完善实验室安全基础设施等相应措施,以保障实验室安全有效的运行和提高教学质量,以期为农林院校土壤学实验室安全管理提供经验和参考。

浅析以安全为评估标准的土壤地理实验室功能分区布局

实验室安全是学校重要的管理工作之一,而合理的实验室设计与功能分区布局,能避免潜在的安全隐患,保证实验室安全管理工作的高效开展。以贵州师范大学土壤地理实验室为例,以安全性能作为评估标准,进行与之相匹配且细致的实验室功能分区布局,不仅提高了实验室的安全性,还保障了各项科研任务的顺利推进,同时也为其他实验室建设提供了参考。

民族师范院校土壤学实验室的利用探析——以阿坝师专为例

《土壤地理学》实践与理论并重,实验室建设的合理与否,会直接影响到专业教学的实际效果。阿坝师专地处西部民族地区,由于限制因素较多,地理实验室发展缓慢,已不能适应市场对人才培养的要求。结合学校专升本机遇和专业定位,提出了丰富实验内容、加强师资队伍建设、野外实习工作等方面的建议,不断改进土壤地理学的实验实践教学,满足专业培养要求。

探析ABC分类法在实验室仪器管理中的运用

针对ABC分类方法在土壤实验室仪器管理中的运用,做了简单的论述,提出了方法运用的策略,共享给相关人员参考。从土壤实验室实际来说,存在着各类仪器,用途不同,管理措施不同。采取分类管理的方法,能够实现有效管理。现结合具体实践,进行如下分析。

明尼苏达大学的施肥咨询工作

位于美国中北部地区的明尼苏达州,土地面积5100万英亩,其中农田面积为1600万英亩,主要农作物是小麦、玉米、大豆等,占农田面积的80％左右,是美国主要粮食产区之一。 每年,明尼苏达州使用200万吨化肥。由于化肥价格逐年上涨,农户、肥料制造公司、肥料商都更加重视化肥的合理施用,以获得最佳经济效益。多年来。

Vacuum preloading combined electroosmotic strengthening of ultra-soft soil

To assess the effectiveness of vacuum preloading combined electroosmotic strengthening of ultra-soft soil and study the mechanism of the process, a comprehensive experimental investigation was performed. A laboratory test cell was designed and applied to evaluate the vacuum preloading combined electroosmosis. Several factors were taken into consideration, including the directions of the electroosmotic current and water induced by vacuum preloading and the replenishment of groundwater from the surrounding area. The results indicate that electroosmosis together with vacuum preloading improve the soil strength greatly, with an increase of approximately 60%, and reduce the water content of the soil on the basis of consolidation of vacuum preloading, howeve~ further settlement is not obvious with only 1.7 mm. The reinforcement effect of vacuum preloading combined electroosmosis is better than that of electroosmosis after vacuum preloading. Elemental analysis using X-ray fluorescence proves that the soil strengthening during electroosmotic period in this work is mainly caused by electroosmosis-induced electrochemical reactions, the concentrations of Al2O3 in the VPCEO region increase by 2.2%, 1.5%, and 0.9% at the anode, the midpoint between the electrodes, and the cathode, respectively.

Optimization of Cr(VI) bioremediation in contaminated soil using indigenous bacteria

Bench-scale soil column experiments were carried out to evaluate the effectiveness of Cr（VI） bioremediation process in soils by using indigenous bacteria with the addition of bacteria nutrient media. Effects of particle size, spray intensity, initial Cr（VI） concentration, circulation mode and soil depth on Cr（VI） remediation were studied. Results show that soils after 6 d remediation with spray intensity controlled in the range of 29.6-59.2 mL/min could well fulfill the requirement of concrete aggregate and roadbed material usage, for the leaching toxicity concentration of the Cr（VI） in treated soils under the chosen condition is far less than 5 mg/L The leaching toxicity and fractions of both hexavalent chromium and trivalent chromium from remediated soils were determined and compared with that of untreated soil. The results show that water soluble Cr（VI） declines from 1520.54 mg/kg to 0.68 mg/kg, exchangeable Cr（VI） decreases from 34.83 mg/kg to 0.01 mg/kg and carbonates-bonded Cr（V1） falls from 13.55 mg/kg to 0.68 mg/kg. Meanwhile, a corresponding increase in carbonate-bonded Cr（III）, Fe and Mn oxides-bonded Cr（III） and organic matter-bonded Cr（III） are found. It reveals that indigenous bacteria can leach out water soluble Cr（VI）, exchangeable Cr（VI） and carbonates-bonded Cr（VI） from contaminated soil followed by converting into carbonate-bonded Cr（III）, Fe and Mn oxides-bonded Cr（IlI）, organic matter-bonded Cr（III） and residual Cr（III）.

Calcareous Sodic Soil Reclamation as Affected by Corn Stalk Application and Incubation: A Laboratory Study

A laboratory lysimeter experiment was conducted to investigate the effects of forage corn （Zea rncbys L.） stalk application on the CO2 concentration in soil air and calcareous sodic soil reclamation. The experimental treatments tested were soil exchangeable sodium percentage （ESP） levels of 1, 11, and 19, added corn stalk contents of 0 to 36 g kg^-1, and incubation durations of 30 and 60 days. The experimental results indicated that corn stalk application and incubation significantly increased CO2 partial pressure in soil profile and lowered pH value in soil solution, subsequently increased native CaCO3 mineral dissolution and electrolyte concentration of soil solution, and finally significantly contributed to reduction on soil sodicity level. The reclamation efficiency of calcareous sodic soils increased with the added corn stalk. When corn stalks were added at the rates of 22 and 34 g kg^-1 into the soil with initial ESP of 19, its ESP value was decreased by 56% and 78%, respectively, after incubation of 60 days and the leaching of 6.5 pore volumes （about 48 L of percolation water） with distilled water. Therefore, crop stalk application and incubation could be used as a choice to reclaim moderate calcareous sodic soils or as a supplement of phytoremediation to improve reclamation efficiency.

Effects of soil moisture and soil depth on nitrogen mineralization process under Mongolian pine plantations in Zhanggutai sandy land, P. R. China

The rates of soil N mineralization at soil depths of 0-15, 15-30, 30-45 and45-60 cm and moisture regimes were measured at three sand-fixation plantations of Pinus sylvestrisvar. mongolica by laboratory aerobic incubation method. The results showed that average rates ofsoil net N-mineralization across soil depth varied from 1.06 to 7.52 mg · kg^(-1)·month^(-1) atsoil depths from 0 to 60 cm. Statistical analyses indicated that the effects of different soildepths, moistures and their interactions on net N-mineralization rates were significant (P < 0.05).The net N-mineralization rates significantly decreased with increasing soil depths and at depth 0-15cm accounted for 60.52% of that at depth of 0-60 cm. There was no difference in soil netN-mineralization rates between half and fully-saturated water treatments, however these rates weresubstantially higher than that without water treatment (P < 0.05). The factors influencing Nmineralization process have to be studied further in these semiarid pine ecosystems.

An Alternative Approach for the Determination of Soil Water Mobility

A new laboratory method was proposed to establish an easily performed standard for the determination of mobile soil water close to real conditions during the infiltration and redistribution of water in a soil. It consisted of applying a water volume with a tracer ion on top of an undisturbed ring sample on a pressure plate under a known suction or pressure head. Afterwards, soil water mobility was determined by analyzing the tracer-ion concentration in the soil sample. Soil water mobility showed to be a function of the applied water volume. No relation between soil water mobility and applied pressure head could be established with data from the present cxperiment. A simple one- or two-parameter equation can be fitted to the experimental data to parameterize soil water mobility as a function of applied solute volume. Sandy soils showed higher mobility than loamy＂ soils at low values of applied solute volumes, and both sandy and loamy soils showed an almost complete mobility at high applied solute volumes.

Research on effect of clogging process on permeability of loose dam foundation of plateau reservoir

Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of clogging process on permeability of loose dam foundation of plateau reservoir.Through laboratory test,the soil can cause clogging effect by itself,and the effect of clogging is relative to the water pressure.The clogging effect can be caused obviously by adding fine particles,and the clogging effect of the particles with 0.063-0.25 mm diameter is best,which verifies the rationality of the optimal diameter interval.It provides the realistic significance for the anti-seepage of the plateau reservoir dam foundation.

Exploring Salinity Perception in Lower Cheliff Plain （Algeria）

Salinity is a well known phenomenon throughout the agricultural fields of Algeria, where irrigation uses poor quality waters. This paper describes the results of a survey of farmers＇ perception of salinity with regard to salinity assessment. In the lower Cheliff plain, 42 farmers were interviewed using semi-structured questionnaires, and simultaneously, water and soil＇s salinity were measured in the laboratory. The results from this sample analysis were compared to the farmers＇ individual opinion on soil and water salinity. Conclusions point to a positive agreement between the two approaches because farmers are familiar with techniques and strategies to mitigate salinity effects. However, they do not perceive the risk of newly changing irrigation water source, which open up to soil degradation hazard.

Greywater Reuse Assessments on Different Soil Types in Baghdad City

he effects of greywater irrigation on four commonly used agricultural soils and models were studied. Sand, sandy loam, sandy clay and light clay soils were selected as common Iraq soils. Soil＇s chemical and physical properties under different irrigation regimes were daily measured during period extended from February 2011 to April 2012 in Baghdad city and plant growth was monitored. A lab scale models of four acrylic columns of 100 mm diameter and 750 mm height were designed and constructed in environmental hydraulic lab at Mustansiriya University and tests were run concurrently with the characterization study to assess the effect of soil depth and loading rate on treatment efficiency. Soil samples were carried out in a site that had been drained with greywater for over 14 months. Measurements of greywater and treated greywater had been achieved which contains BODs, COD, pH, EC, TDS, turbidity, CI＋1, 504＋2, NO3＋1, Na＋l, Ca＋2, Mg＋2, E coli and coliform.

Environmental Factors Affecting Chromium-Manganese Oxidation-Reduction Reactions in Soil

Disposal of chromium （Cr） hexavalent form, Cr（Ⅵ）, in soils as additions in organic fertilizers, liming materials or plant nutrient sources can be dangerous since Cr（Ⅵ） can be highly toxic to plants, animals, and humans. In order to explore soil conditions that lead to Cr（Ⅵ） generation, this study were performed using a Paleudult （Dystic Nitosol） from a region that has a high concentration of tannery operations in the Rio Crande do Sul State, southern Brazil. Three laboratory incubation experiments were carried out to examine the influences of soil moisture content and concentration of cobalt and organic matter additions on soil Cr（Ⅵ） formation and release and manganese （Mn） oxide reduction with a salt of chromium chloride （CrCl3） and tannery sludge as inorganic and organic sources of Cr（Ⅲ）, respectively. The amount of Cr（Ⅲ） oxidation depended on the concentration of easily reducible Mn oxides and the oxidation was more intense at the soil water contents in which Mn（Ⅲ/Ⅳ） oxides were more stable. Soluble organic compounds in soil decreased Cr（Ⅵ） formation due to Cr（Ⅲ） complexation. This mechanism also resulted in the decrease in the oxidation of Cr（Ⅲ） due to the tannery sludge additions. Chromium（Ⅲ） oxidation to Cr（Ⅵ） at the solid/solution interface involved the following mechanisms： the formation of a precursor complex on manganese （Mn） oxide surfaces, followed by electron transfer from Cr（Ⅲ） to Mn（Ⅲ or Ⅳ）, the formation of a successor complex with Mn（Ⅱ） and Cr（Ⅵ）, and the breakdown of the successor complex and release of Mn（Ⅱ） and Cr（Ⅵ） into the soil solution.

Responses of Soil Microbial Activity and Biomass to Salinity After Repeated Additions of Plant Residues

Microbial adaptation to salinity can be achieved through synthesis of organic osmolytes,which requires high amounts of energy;however,a single addition of plant residues can only temporarily improve energy supply to soil microbes.Therefore,a laboratory incubation experiment was conducted to evaluate the responses of soil microbes to increasing salinity with repeated additions of plant residues using a loamy sand soil with an electrical conductivity in saturated paste extract(EC_e) of 0.6 dS m^(-1).The soil was kept non-saline or salinized by adding different amounts of NaCl to achieve EC_e of 12.5,25.0 and 50.0 dS m^(-1).The non-saline soil and the saline soils were amended with finely ground pea residues at two rates equivalent to 3.9 and 7.8 g C kg^(-1) soil on days 0,15 and29.The soils receiving no residues were included as a control.Cumulative respiration per g C added over 2 weeks after each residue addition was always greater at 3.9 than 7.8 g C kg^(-1) soil and higher in the non-saline soil than in the saline soils.In the saline soils,the cumulative respiration per g C added was higher after the second and third additions than after the first addition except with3.9 g C kg^(-1) at EC_e of 50 dS m^(_1).Though with the same amount of C added(7.8 g C kg^(-1)),salinity reduced soil respiration to a lesser extent when 3.9 g C kg^(-1) was added twice compared to a single addition of 7.8 g C kg^(-1).After the third residue addition,the microbial biomass C concentration was significantly lower in the soils with EC_e of 25 and 50 dS m^(_1) than in the non-saline soil at3.9 g C kg^(-1),but only in the soil with EC_e of 50 dS m^(-1) at 7.8 g C kg^(-1).We concluded that repeated residue additions increased the adaptation of soil microbial community to salinity,which was likely due to high C availability providing microbes with the energy needed for synthesis of organic osmolytes.

Experimental and Modeling Study of Forest Fire Effect on Soil Thermal Conductivity

An understanding of soil thermal conductivity after a wildfire or controlled burn is important to land management and post-fire recovery efforts. Although soil thermal conductivity has been well studied for non-fire heated soils, comprehensive data that evaluate the long-term effect of extreme heating from a fire on the soil thermal conductivity are limited. The purpose of this study was to evaluate the long-term impact of fire on the effective thermal conductivity of soils by directly comparing fire-heated and no-fire control soils through a series of laboratory studies. The thermal conductivity was measured for ten soil samples from two sites within the Manitou Experimental Forest, Colorado, USA, for a range of water contents from saturation to the residual degree of saturation. The thermal conductivity measured was compared with independent estimates made using three empirical models from literature, including the Campbell et al. （1994）, CSt~ and Konrad （2005）, and Massman et al. （2008） models. Results demonstrate that for the test soils studied, the thermal conductivity of the fire-heated soils was slightly lower than that of the control soils for all observed water contents. Modeling results show that the Campbell et al. （1994） model gave the best agreement over the full range of water contents when proper fitting parameters were employed. Further studies are needed to evaluate the significance of including the influence of fire burn on the thermal properties of soils in modeling studies.