多阶梯边坡植被恢复技术在公路建设中的应用

以京承高速公路密云沙峪沟—市界段为例,介绍施工中采用的以客土喷播技术与基质喷附技术相结合的一种边坡植被恢复技术——多阶梯边坡植被恢复技术.该技术通过削坡机将陡坡修成一定高宽比的多阶梯状边坡,沿阶梯面铺设护坡网,将混有一定比例的植物种基质喷附在每一级坡面上;同时在各平台面客土进行乔灌木建植喷播等一系列施工流程,结合对坡面的养护管理,保证边坡的稳定性,提高植被恢复的成功率,达到坡面植被恢复与绿化的效果.多阶梯边坡植被恢复技术具有稳定边坡,减少水土流失,美化边坡环境等优点,可为同类边坡植被恢复施工提供参考.     

狼窝沟小流域废弃煤窑生态修复技术初探

针对狼窝沟小流域山坡面积大、山高、坡陡和煤窑废弃后煤炭乱挖滥采现象仍较严重等状况,采取整地并客土、完善排水系统、工程和植被护坡、植被恢复等生态修复措施,以达到控制水土流失、提高土地利用率和增加当地群众收入的目的,为小流域的可持续发展奠定坚实的基础。     

狼窝沟小流域废弃煤窑生态修复技术初探

针对北京市门头沟区狼窝沟小流域山坡面积大、山高、坡陡和煤窑废弃后煤炭乱挖滥采现象仍较严重等状况,采取整地并客土、完善排水系统、工程和植被护坡、植被恢复等生态修复措施,以达到控制水土流失、提高土地利用率和增加当地群众收入的目的,为小流域经济社会的可持续发展奠定坚实的基础。     

泰山抽水蓄能电站扰动区不同植被恢复措施效果研究

以泰山抽水蓄能电站扰动区为研究对象，通过野外调查与室内分析方法，分析了不同植被恢复措施的效果及其影响因素。结果表明：扰动区开挖量大，基岩裸露，无土层覆盖，缺乏植被适生的水土条件，需辅助挡墙、悬挂垒砌植穴、垒砌石质鱼鳞坑等工程措施与客土进行植被恢复。不同植被恢复措施油松的造林成活率与保存率均以绿化平台最高，垒砌悬挂复绿法最差；不同措施的高生长与径生长量大小顺序均为东北坡向鱼鳞坑〉坝后坡绿化平台〉东南坡向鱼鳞坑〉垒砌悬挂复绿法。不同植被恢复措施的客土质地、容重、总孔隙度等物理性状均对油松生长产生影响；客土深度大有助于油松的生长，但在客土量相当的情况下，小规格植穴的生长量要好于大规格植穴的生长量；油松高生长（y）与客土量（x）间呈Y=alnX＋b的对数相关关系，但径生长量与客土量间关系不明显。     

挡土翼工法在石质边坡生态恢复中的应用研究

如何增强客土土体抗侵蚀性和稳定性,对石质边坡生态恢复建设有着重要的意义.提出了挡土翼工法的设计技术出发点以及具体施工工法,并在庆丰生态治理工程中对挡土翼的实际生态恢复效能进行监测.监测结果发现现石质边坡生态恢复采用了挡土翼工法坡面比未采用挡土翼工法坡面先锋植被建立时间快,土体侵蚀情况明显减少,坡面土体厚度可增加4～7 cm,极具推广应用价值.     

岩石边坡植被恢复工程中的客土稳定性分析

[目的]讨论岩石边坡植被恢复工程中的客土稳定性计算方法,为该类工程的稳定性评价提供依据。[方法]模拟计算抗剪型和摩擦型根系产生的作用力,转换为抗剪强度后作为客土稳定性的附加值,进而推导出稳定性计算公式,并通过济南—莱芜高速公路的客土喷播工程案例进行实测和验证。[结果](1)客土稳定性系数取决于无根土抗剪强度(Fs)、客土容重(γ)、客土厚度(d)、根系抗剪强度增量(τR);(2)根系产生的抗剪强度可细分抗剪型根系抗剪应力(τRg)和摩擦型根系抗剪应力(τRf)二者之和;(3)稳定性计算值始终小于实测值,分布规律及偏差值较稳定,植被恢复初期的3~5a内客土稳定性系数与植被恢复期成明显的正相关关系。[结论]客土稳定性系数计算可以作为岩石边坡植被恢复工程的参数设计和稳定性评价方法。     

现场喷注混凝土自由框格防护及客土绿化技术试验研究

现场喷注自由框格防护客土绿化技术及其在湖南岩质边坡上的试验效果表明该技术不仅可有效防止坡面迅速风化导致的失稳,保证坡面的力学稳定,配合客土喷播技术进行坡面绿化,最终通过植被演替形成与周边环境协调一致的植被与景观;而且具有适应性强、性价比高的特点,适合在各种风化、半风化高陡岩质边坡及各种不稳定边坡的防护与绿化中使用,具有广泛的推广价值.     

张承地区光伏发电项目水土流失特点及防治措施

以河北张承地区15个光伏发电项目为例,介绍了该地区的太阳能资源概况,分析总结了项目建设水土流失特点及防治措施。光伏发电项目水土流失特点表现为点状与线状侵蚀兼有,风蚀与水蚀共存等。适合采取的工程措施主要包括表土剥离和回铺、高陡边坡防护、坡面汇流区截排水沟建设等;植物措施主要是针对不同施工区域选择适宜的乡土树草种进行植被恢复,对线状施工区可采用分段施工、植被移植的方法恢复植被,并且在施工中要合理安排施工时序和施工期临时防护措施。     

曼大公路仙米自然保护区标段取土场边坡生态修复措施

[目的]探讨青藏高原仙米自然保护区取土场生态修复技术的关键技术措施,为高原保护区边坡生态修复提供借鉴。[方法]以穿越仙米国家森林公园自然保护区的国道569曼德拉至大通高速公路NKSG4标段4#取土场边坡为例,基于取土场当地气候特点、地质土壤及植被状况,详细介绍了取土场生态修复的关键技术措施,包括取土场削坡、坡顶截水沟、平台排水沟及急流槽等措施,客土绿化及客土喷播生态修复工法要点,以及选择披碱草、冷地早熟禾、星星草、油菜和豌豆混合物种的具体配比。[结果]施工后1a的效果表明:排水沟体系排水效果良好,坡底无积水,坡面保持完整且无水土流失;客土绿化坡面植被覆盖率达到80%以上,客土喷播坡面植被覆盖率达到85%以上。[结论]取土场的生态修复效果达到要求;在进行生态修复时应尽量利用当地资源,以实现生态效益和经济效益最大化。     

半干旱区生态护坡工程客土养分衰减特征与恢复趋势

以山东省中部半干旱区济青南线高速公路部分石质边坡客土喷播生态防护试验工程为对象,通过对生态护坡试验工程客土土壤的有机质含量和碱解氮含量等进行现场跟踪测试,分析客土养分衰减与恢复变化规律。研究结果表明,有机质和碱解氮含量随着时间的延长出现了不同程度的衰减特征,而且碱解氮含量在4个月后出现年内稳定恢复的迹象,而有机质含量则在半年内仍未停止衰减过程,客土养分的恢复尚需时日;由于衰减机理的差异,不同坡面部位的碱解氮和有机质含量衰减转折点和时间效应不尽相同,可以预期未来随着植被落叶等自身有机物质的腐烂和养分补给,能够实现坡面植物营养的自给与客土养分的恢复。研究成果对开发贫瘠土壤和石质边坡生态植被恢复技术具有重要现实意义。     

pH对磷钾铝石形成的影响

Effects of column temperature and flow rate on separation of organic acids were studied by determining nine low-molecular-weight organic acids on reversed-phase C18 column using high performace liquid chromatography(HPLC) with a wavelength of UV(ultraviolet)214 nm and a mobile phase of 18 mmol L^-1 KH2PO4 buffer solution (pH2.1).The thermal stabiltiy of organic acids was determined by comparing the recoveries of organic acids in different temperature treatments.The relationships between column temperature,flow rate or solvent pH and retention time were analyzed.At low solvent pH,separatioin efficiency of organic acids was increased by raising the flow rate of the solvent because of lowering the retention time or organic acids.High column temperature was unfavorable for the separation of organic acids.The separating effect can be enhanced through reducing column temperature in organic acid determination due to increasing retention time.High thermal stability of organic acids with low concentrations was observed at temperature of 40℃-45℃,Sensitivity and separation effect of organic acid determination by HPLC were clearly improved by a combination of raising flow rate and lowering column temperature at low solvent pH.     

Emission of carbon dioxide and dynamics of inorganic N in a gradient of alkaline saline soils of the former lake Texcoco

A plan was developed to apply biosolid to soil of the former lake Texcoco to fertilize the pioneer vegetation. Because, no information exists about how differences in electrolytic conductivity (EC) might affect mineralization of biosolid and dynamics of C and N in soil, 20 soil samples forming a gradient in EC ranging from 22 to 150 dS m⁻¹ were characterized, amended with 500 mg biosolid C kg⁻¹ dry soil and incubated aerobically at 22 ± 2 °C while production of CO₂, concentrations of ammonium (NH₄⁺), nitrite (NO₂⁻), and nitrate (NO₃⁻), and NH₃ volatilization were monitored at 22 ± 2 °C for 70 days. Soil characteristics showed large variations with maximum values often >10-times larger than minimum values. The production of CO₂ in the unamended soil ranged from 25 to 159 mg CO₂-C kg⁻¹ day⁻¹ and NH₃ volatilization from 0 to 189 μg NH₃-N kg⁻¹ day⁻¹_. Application of biosolid increased production of CO₂ significantly 1.4-fold and volatilization of NH₃ 11.5-fold. The EC explained most of the variation in production of CO₂, while particle size distribution explained most of the variation in volatilization of NH₃. The concentration of NH₄⁺ in the biosolid-amended soil decreased sharply in the first 14 days, with the EC explaining most of the variation found, and remained constant thereafter with a small increase at day 70. Significant increases in the concentration of NO₃⁻ were generally found in soil with EC < 64 dS m⁻¹. The EC explained most of the variation in production of CO₂, and dynamics of NH₄⁺ and NO₃⁻ while clay positively and sand content negatively affected NH₃ volatilization. It was found that increases in EC inhibited C and N mineralization in soil of the former lake Texcoco.     

Hydrochemistry of Waters of Volcanic Rocks: The Case of The Volcanosedimentary Rocks of Thrace, Greece

This work is referred to the characterization of the environmental hydrochemistry in the broader Sapes area – Thrace region, on the basis of physico-chemical properties of surface and groundwaters occurring in the volcanosedimentary formations of this area, where gold mining activities are planned to operate. Volcanic rocks are considerably altered where they are in contact with hydrothermal solutions. Aquifers are formed within these formations. Surface and ground waters are strongly metalliferous and their hydrochemical facies present similar but complex water types. Certain characteristic chemical types are the following: Ca-Mg-HCO₃-SO₄, Ca-Mg-SO₄-HCO₃. Ca-SO₄, Ca-Mg-SO₄. Ca-Na-Cl-HCO₃, Na-Cl. A small majority of the water samples present the following order of anion dominance HCO₃ ^? > SO₄ ^2? > Cl^?. Calcium is the dominant cation. Bicarbonates and sulfate ions are the dominant anions. The order of dominance for the heavy metals in surface and ground waters is as follows: Fe > Mn > Zn > Ni > Cu. The saturation index of waters regarding minerals is low. Computer simulation indicates that calcite and dolomite are common minerals in all water samples which are saturated in respect to quartz and argillaceous-siliceous minerals. The most pronounced property of waters is their acidic character. The high metal concentrations are related to water with low pH. Sulfide minerals control the low pH values of waters which is an important control factor for the evolution of the water chemical composition. The abundance of sulfates is attributed to the dissolution of the minerals pyrite (FeS₂) and alunite (KAl₃(SO₄)₂(OH)₆. The water–mineral interactions are responsible for the chemical composition of waters. Water quality problems can be successfully handled by the use factor analysis. 17 chemical parameters can be substituted by five factors which successfully represent the hydrochemical processes as well as their geographic distribution. Volcanic rocks in the study area have the potential to produce acid drainage.     

华北土石山区天然植被种间联结和生态位研究

 在华北土石山区潮关西沟流域天然森林植被调查的基础上,对森林植被群落种间联结和生态位进行研究。结果表明:种间正联结关系非常显著的有柞栎和蒙椴、柞栎和迎红杜鹃、蒙椴和山杨、蒙椴和白蜡、山杨和白蜡、春榆和北京丁香、春榆和大花溲疏、臭椿和山杏、臭檀和栾树、臭檀和大花溲疏、锐齿鼠李和孩儿拳头、小叶鼠李和酸枣。另外,依据种间联结关系,划分了4个生态种组。分析了主要乔灌木的生态位宽度,乔木树种蒙椴、柞栎、春榆和灌木树种荆条、小叶朴和酸枣的生态位宽度均较大。比较了不同种对的生态位重叠指数,乔木不同种对中,山杏和北京丁香、柞栎和白蜡、蒙椴和春榆具有较大的生态位重叠,灌木不同种对组合中,荆条和酸枣、绣线菊和迎红杜鹃、荆条和小叶朴、蚂蚱腿子和迎红杜鹃的生态位重叠较大。     

Mechanisms of persistence of low numbers of bacteria preyed upon by protozoa

Tetrahymena pyriformis cultures were maintained when transferred serially in solutions containing 10⁵ to 10⁷Klebsiella pneumoniae cells.ml^?1, bacterial numbers that were observed to persist in the presence of protozoa. The number of cells of one strain of K. pneumoniae surviving predation in solution was essentially the same in the absence of an alternative prey as in the presence of a second K. pneumoniae strain. Toxins deleterious to protozoa did not appear as the animal consumed the bacteria. T. pyriformis reduced the abundance of Escherichia coli from about 10⁸ to 10⁶.ml^?1. but the latter number persisted for 15 days; however, in solutions containing chloramphenicol, the abundance of E. coli fell to 590 cells. ml^?1 in 15 days. In solutions containing the antibiotic, T. pyriformis reduced the Rhizobium sp. population from more than 10⁶ to less than 10³ cells in 10 days and K. pneumoniae from more than 10⁸.ml^?1 to zero in 18 days. An appreciable decline in abundance of these bacteria did not occur in the antibiotic-amended liquid free of protozoa. T. pyriformis did not greatly reduce Rhizobium sp. numbers when both were added to irradiated soil, but the predator caused the bacterial population to decline from 4 × 10⁸ to fewer than 10⁵.g^?1 in 16 days in chloramphenicol-treated soil. Colpoda sp. inoculated with Rhizobium sp. into soil sterilized by autoclaving only reduced the prey abundance from 10⁹ to 10⁸.g^?1, but the protozoan caused the bacterial population to fall to about 100.g^?1 in 15 days in the presence of the antibiotic. The population of Rhizobium sp. added to nonsterile soil dropped from in excess of 10⁸ to 6 × 10⁶.g^?1 in 29 days. but it declined to 550. g^?1 in the same period when chloramphenicol was also introduced. It is concluded that the ability of these bacteria to maintain themselves in solution and in soil is governed by their capacity to reproduce and replace the cells consumed by predation.     

Evidence of Long-Range Transport of Pollutants from the Size-Fractionated Ionic Composition of Aerosols in the Jeju Island of Korea

The ionic composition of total suspended particulate (TSP) and fine (PM_2.5) fractions was investigated from an 1,100 site in the middle of Mt. Halla in Jeju Island, Korea from March to November 2006. The sum concentrations of cation and anion species in TSP fraction were 205 ± 170 and 183 ± 164 neq m^?3, respectively, while those for PM_2.5 as 118 ± 129 and 88.5 ± 89.3 neq m^?3, respectively. In TSP, the concentration of the major ions changed in the order of SO₄ ^2? > NH₄ ⁺ > Ca²⁺ > Na⁺ > NO₃ ^? > Mg²⁺ > K⁺ > Cl^?, while its PM_2.5 counterpart as NH₄ ⁺ > SO₄ ^2? > Ca²⁺ > NO₃ ^? > Na⁺ > Mg²⁺ > K⁺ > Cl^?. Inspection of the temporal variabilities of ionic components indicated that most ions peaked in spring or fall months. The back trajectory analysis showed that the atmospheric composition of the major ionic species was affected fairly sensitively by long-range transport from China under the favorable meteorological conditions. In contrast, the lowest ionic concentration levels were seen most abundantly, when air masses passed from South Sea. Hence, the analysis of ionic concentration data suggests that their distributions are controlled by the combined effects of various source processes including the most prominent Chinese origin and the meteorological condition favorable for such transport.     

Effect of reducing conditions on P sorption of soils

Abstract

The phosphate sorption (P _sor) capacity of soils increased when the soils were reduced (Willet and Higgins, Aust. J. Soil Res., 16, 319–326, 1978). The present study aimed at the elucidation of this mechanism using Na₂S₂O₄ and 5 different soils. The P _sor of the 5 soils increased with the addition of a small amount of Na₂S₂O₄. Fe(II) was released from the soils with the addition of the same small amount of Na₂S₂O₄. Furthermore, when the amount of FeCl₂ corresponding to the amount of Fe(II) released along with the small amount of Na₂S₂O₄ was added, the P _sor of the soil increased. However, the P _sor of the lowland soils, of which the hydrous Fe oxide content was lower than the others, decreased when the amount of Na₂S₂O₄ addition was increased up to 150–200 g kg^?1. Based on these results, the following process is inferred for the increase in the P _sor of the soils when they are reduced. Hydrous Fe oxide in soil takes the form of very fine, high-density particles and reacts with P mainly on their surface. When a small amount of Na₂S₂O₄ is added, the hydrous Fe oxide is partially reduced, dissolved and finally re-precipitates with P by oxidation with O₂ from the air during the experiment.     

Effect of Timing of Sulfur Fertilizer Application on Growth and Yield of Rapeseed

Abstract

There is usually a positive yield response when sulfur (S) is applied to rapeseed (Brassica rapa L.) plants grown on S-deficient soils. Recommendations include application of some of or the entire amount of S at planting, but the plant requirement as well as availability of S to rapeseed during its various phenological stages is not well documented. In a field trial, 40 kg S ha^?1 was applied as gypsum (CaSO₄·2H₂O) at planting (T₁), during vegetative (T₂, 30 days after sowing), flowering (T₃, 50 days after sowing), and pod-filling (T₄, 65 days after sowing) stages, and in split doses (T₅). Biomass accumulation, leaf-area index, and leaf photosynthetic rate were studied at various growth stages. Seed S (sulfate and organic S) and yield parameters were studied at harvest. Sulfur (40 kg S ha^{? 1}) applied in three split doses during different growth stages caused maximum increase in these parameters, followed by T₂ and T₁. However, no significant discernable difference was observed for the application at planting (T₁) and during vegetative stage (T₂). No significant response was seen following the application of T₃ and T₄ when compared with the control (T₀). On the basis of these results, we concluded that application of S fertilizer in split doses during growth stages is better than application of the entire amount of S at any stage for obtaining optimum yield of rapeseed.     

Determination of surface charge density of soils

Abstract

A simple and precise method for determination of surface charge density of soils is described. It involves saturating the negative and positive exchange sites with NH⁺ ₄ and NO^‐ ₃ ions, respectively, removing the excess solution by centrifugation, and determining the ions on the exchange sites by a steam distillation method. Results showed that the concentration and type of saturating ions and the extractant used significantly affected the surface negative charge densities. The average value of surface negative charge densities of 10 surface soils from Iowa, Chile, and Costa Rica by the proposed method agreed closely with that obtained by the original method proposed by Schofield in 1949 (14.6 vs. 13.7 cmol(‐) kg^‐1 soil). The advantages of the proposed method are no need for the laborious extraction steps and simplicity of the steam distillation method for determination of NH⁺ ₄ and NO^‐ ₃ in soil samples.     

Evaluation of nitrogen fixation by different strains of theAzolla-Anabaena symbiosis in the presence of a high level of ammonium

Summary The proportion of N derived from N₂ fixation for 99 strains ofAzolla spp. (comprising all known species) in the presence of ammonium (40 mg/1) was assessed using a¹⁵N-dilution technique. The percentage of N derived from air varied from 29.5% to 79.9%. Although the N concentration ofAzolla spp. was not correlated with fertilizer N, it correlated fairly well with N₂ fixation. Regression analysis suggests that the N yield ofAzolla spp. is more dependent on N₂ fixation than on ammonium assimilation. The high correlation between N yield and isotopically determined, fixed N₂ indicates that the N yield could be used as a parameter in the selection ofAzolla spp. strains that are capable of maintaining high N₂ fixation in the presence of a high level of ammonium.