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The application of appropriate excavation equipment in difficult grounds is of crucial importance and consequently improves the performance of hard rock Tunnel Boring Machines (TBMs). The cutterhead is one of the main components of TBMs which is directly involved in the excavation process, and its design can highly affect the cutting efficiency, the overall balance of the head, the performance of main bearing in long term, and the wear of the whole cutting face and muck buckets. This paper mainly focuses on the significant role of a proper design on the cutting efficiency with reference to a TBM tunneling project. Due to existence of very hard and abrasive rocks on the path of Kerman water conveyance tunnel, a new cutterhead was designed to be applied on a second hand TBM. The new cutterhead contains larger 19-inch disc cutters with a new disc cutter layout. Since the new cutterhead was launched following the excavation of the old one in a specific chainage of the tunnel, the performance of the two cutterheads in pyroclastic rocks could be compared with respect to the cutting efficiency, and lower specific energy values were observed for the new cutterhead which is the indicator of a better cutting efficiency in this geological condition.

In south Florida sugarcane is cultivated on muck and sandy soils. The cane yield (CY) of varieties grown on sandy soils is substantially lower than on muck soils due to water and nutrients stress. High CY combined with good ratooning ability (RA) is important for profitable sugarcane cultivation. In this study three series of CP trials (CP 2009, CP 2010, and CP 2011) planted in 3–4 locations with sandy soils were evaluated during 3 crop cycles. Our goals were to assess the magnitude of the sources of variation in the final selection stage (Stage 4) in the CP program for sandy soils, and to select sugarcane genotypes for sandy soils with high CY, good RA, and performance stability across sand locations. Variability of CY on sandy soils depended on crop and crop × location interaction. Genotype × crop × location interaction was significant in two out of three CP series, highlighting the complexity associated with breeding for CY on sandy soils in Florida. There were significant differences for CY among genotypes of CP 2011 series, but a limited RA diversity was detected among genotypes. The genotype plus genotype × environment (GEE) interaction analysis conducted with the combined CY data of CP 2011 series showed that Pahokee Produce Inc. (PPI) and Lykes locations were the most discriminant locations, whereas Hilliard and Townsite were the most representative sand locations in Florida. The simultaneous selection for CY, RA and stability identified outstanding genotypes in the CP 2011 series such as CP 11-1314 and CP 11-1640.

During tunnel boring machine (TBM) excavation, scrapers play the role in shoveling the broken rock fragments, directly contacting with them, which may result in seriously wear and failure, causing high economic loss. Therefore, it is an urgent problem to study the wear mechanism of scraper and how to reduce the blade wear. In this study, the wear prediction model of scraper was established based on working mechanism and wear mechanism analysis. The factors influence on wear characteristic were obtained. Then, the numerical model of TBM scraper shoveling the muck was established using discrete element method. The shovel capacity and wear characteristic of scraper were studied. The structural parameters of blade were optimal designed, comprehensively considering the shovel capacity and wear characteristics. The results indicate that abrasive wear is the main type of scraper wear. The main influencing factors of scraper wear are blade angles. When the front angle of the blade is 25° and the back angle is 8°, the wear performance of the scraper would be improved. The optimal results were successfully applied to a tunneling project and the actual data in the engineering construction of the scraper during the construction were analyzed to verify the structural design method of TBM scraper.

Soil conditioning is an important stage in shield tunnel construction that can effectively improve muck flow plasticity, reduce cutter head wear and improve tunneling efficiency, especially in sandy and cobbly soils. The aim of this paper is to obtain the optimal ratio of residue modifiers in sandy and cobbly soil and to improve the equipment used in residue-related shield machines. Residual soil in a sandy pebble layer was selected, and particles with sizes over 50 mm were removed to form soil samples. Through laboratory tests, the optimal ratio of the modifier was obtained, and the shield tunneling machine equipment was optimized. The research results for the laboratory tests and equipment optimization were verified and adjusted appropriately through field tunneling tests. The following results were obtained. 1) A 3% foaming agent C was selected for the soil conditioning tests. The final mass ratio of the bentonite mixed solution of water, bentonite, soda ash (Na2CO3), and carboxymethyl cellulose (CMC) was 6:1:0.028:0.035. 2) Improving earth pressure balance (EPB) shield machine equipment can improve the effects of soil conditioning. 3) Compared with the volume of residual soil, the optimal ratio of soil conditioning in sandy and cobbly layer was 13% water, 4–5% bentonite mixed solution and 12–15% foam. In addition, the maximum ratio shall be taken for the strata with poor grain composition. These results can be used to provide excavation guidelines for using an EPB machine under these soil conditions.

Emerald ash borer (EAB) (Agrilus planipennis) has had an extensive impact across North America. It is currently present in Minnesota, USA but has not been observed in northern portions of the state where the vast majority of black ash (Fraxinus nigra) trees are located. Unlike other ash forest communities, the black ash forest type occurs in wetlands and is dominated by black ash with few associate species. Because of this, the loss of black ash can result in changes to the hydrological regime and species composition. The goal of this study was to quantify the structure and composition of regeneration 5 to 11 years post-harvest in three silvicultural systems (group selection, clearcut, and diameter-limit harvesting) to evaluate the potential for establishment of other tree species. Overall, regeneration post-harvest was high but variable across all systems. Across silvicultural systems, there was no significant relationships between residual overstory trees (> 10 cm dbh) basal area and non-ash regeneration TPH, indicating flexibility in designing treatments for diversification. Populus sapling (2.54–10 cm) density was significantly negatively correlated to the depth of the soil muck layer. In contrast, a positive relationship was observed between depth of the soil muck and black ash saplings. These findings indicate that specific silvicultural systems in combination with site quality (e.g., clearcuts on high-quality sites with shallow muck layers) may help to promote non-ash species in black ash forests that are threatened with EAB.

A computational scheme coupling PFC3D (Particle Flow Code in 3 Dimensions) and FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) was performed to investigate influences of sand conditioning on the tunneling behaviour of earth pressure balance (EPB) shield in sandy ground. A detailed EPB shield and its near ground were modelled in the PFC3D while the other ground was simulated in the FLAC3D. Decreasing friction coefficients were used to characterize the fluidity improvement of conditioned muck particles. The results indicate that the residence time of muck in the excavation chamber is associated with its position and rotation directions of the spoke. The muck pressure and its difference in front of and behind the cutterhead decrease with the improvement of conditioning degree in a certain conditioning range, and an appropriate soil conditioning scheme can facilitate the control of chamber pressure. In addition, the torque of cutterhead decreases more significantly than the thrust with an improvement of soil conditioning degree within a normal conditioning range.

Scenarios modeling can be a useful tool to plan for climate change. In this study, we help Everglades restoration planning to bolster climate change resiliency by simulating plausible ecosystem responses to three climate change scenarios: a Baseline scenario of 2010 climate, and two scenarios that both included 1.5 °C warming and 7% increase in evapotranspiration, and differed only by rainfall: either increase or decrease by 10%. In conjunction with output from a water-use management model, we used these scenarios to drive the Everglades Landscape Model to simulate changes in a suite of parameters that include both hydrologic drivers and changes to soil pattern and process. In this paper we focus on the freshwater wetlands; sea level rise is specifically addressed in prior work. The decreased rainfall scenario produced marked changes across the system in comparison to the Baseline scenario. Most notably, muck fire risk was elevated for 49% of the period of simulation in one of the three indicator regions. Surface water flow velocity slowed drastically across most of the system, which may impair soil processes related to maintaining landscape patterning. Due to lower flow volumes, this scenario produced decreases in parameters related to flow-loading, such as phosphorus accumulation in the soil, and methylmercury production risk. The increased rainfall scenario was hydrologically similar to the Baseline scenario due to existing water management rules. A key change was phosphorus accumulation in the soil, an effect of flow-loading due to higher inflow from water control structures in this scenario.

The application of seaweeds as muck in agricultural farming has been very common from ancient times in the Roman Empire, Japan, China, France, Spain, Britain, etc. Most coastal areas all over the world use seaweeds as bio-fertilizer for crop production. Seaweed extracts are used in different ways like seed treatment, foliar spray and soil application for plant protection and for plant growth promotion. Seaweed extract is more useful than chemical fertilizer because of its bio-decomposable, non-toxic and eco-friendly property. These are the most important reasons to use seaweed extracts in recent years for sustainable agriculture in organic and integrated organic farming. Seaweeds affect agricultural crops for enhancement of plant growth, seedling growth, both root hair and secondary root development. It can also improve nutrient incorporation, fruit setting, resistance properties against pests and diseases, improving the stress management (drought, salinity and temperature). The present review focused on use of seaweed extract in the agricultural system and novel strategies for the use of seaweed extract.

Wet muck entry is one of the major geotechnical risks associated with long-term production goals in cave mining. The objective of this research is to quantify the effect of the main risk variables related to wet muck entry in an effort to prioritize and confront these variables accordingly. Logistic regression modeling was carried out using mine data from Pipa Norte Mine (PNM) and Sur Andes Pipa Mine (SPM), both located at El Teniente Mine. A confusion table was employed to calibrate the model, while a scatter plot and an error relative frequency histogram were used to validate it. The results indicated that ore draw and environmental conditions are the main risk variables associated with wet muck entry. The aforementioned metrics show an acceptable agreement between mine and modeled data. Hence, we used these results to create a statistically significant predictive model, which may be useful for the risk evaluation of numerous long-term plans. Based on optimal calibrated conditions, the predictive model is a powerful instrument not only to identify high-risk zones susceptible to wet muck entry but also to make long-term preventive decisions, which could lead in mitigating the risks of wet muck entry in cave mines.

Rock strength is one of the most important parameters in geotechnical engineering. During excavation using a tunnel boring machine (TBM), a rapid and effective method to estimate rock strength is needed. The TBM muck produced during excavation contains blocky fragments which are suitable for a point load test (PLT). To use the PLT on blocky fragments to estimate rock strength, it is necessary to find the relation between the point load strength (PLS) of blocky fragments and uniaxial compressive strength (UCS) of surrounding rocks. In the present study, PLT was performed on both blocky fragments and core samples of limestone for the Yinsong Water Conveyance Project, China. The UCS of limestone was acquired. The PLS of blocky fragments and core samples was compared. The results show that the blocky fragments’ PLS is lower than that of core samples; the declining ratio depends on the fractured degree of sampling sites; blocky fragments with width and thickness in a certain range are suitable for estimating rock strength; and when the size of the blocky fragment exceeds a certain range, it means the blocky fragment was not generated from the tunnel face. The limestone core samples simultaneously drilled from side wall have an average conversion factor from PLS to UCS of 24.61. The mean conversion factor from PLS of blocky fragments to UCS of limestone in the present study is 40.38.

Collapse of a 7.08-m-deep open cut excavation for the bank of a navigation lock in sensitive soft clay in Zhejiang, China, is presented in this paper. Cone penetration tests, field vane shear tests (VSTs), and traditional laboratory tests have been performed to investigate the soil properties after the collapse. According to the test results, the soft soil layers of mucky clay and muck have been found to be disturbed because of the effects of the boring holes. For bored concrete piles, the stresses release due to the cut slope, thus its shear strength is much lower than that measured from laboratory tests. The shear strength reduction technique based on a finite-element method program has been used to study the excavation behavior and overall factor of safety (FOS) of the excavated slope considering geometries of original design, later adopted schemes and soil properties associated with various test types. The computed FOS values obtained from VST results are lower than the corresponding recommended values and just a little higher than the limited value. Thus the excavated slope may easily collapse triggered by additional vehicles and surface surcharge loads. The reasons of excavation collapse can be explained as the misuse of soil properties for designers, and inadequate construction process management. The investigation of the failure provides experiences and lessons for the design and construction of similar projects in sensitive soft clay.

Fine-grained valley sediments in cold mountain regions can cause frost heave and thaw settlement problems to infrastructure. These processes have caused major issues along a highway between Tanchang County and Diebu County in south Gansu province (the TDH), northwest China. A planned high-speed railway between Chengdu and Xi’ning, the capitals in the Sichuan and Qinghai provinces, will likely face the same problems. To mitigate the effects of frost heave and thaw settlement, new engineering techniques were tested in a valley region along the TDH. These included replacing frost-susceptible subgrade soils with gravels from a tunnel excavation as an anti-frost fill layer, and installing dewatering seepage drains. Two highway test sections were constructed, one with a 1.0-m fill layer and the other with 2.0-m fill layer, to test the performance of the coarse tunneling material as an anti-frost heaving technique. Ground temperature, water table, and deformation measurements indicated that the two sections experienced very limited post-construction settlement (1.5 mm and 1.7 mm). The maximum frost heave at the two sections was 4.0 mm and 10.7 mm, respectively, much lower than the admissible amount in the Chinese standards (50 mm). These results indicate that coarse-grained waste material from tunneling can be used to effectively control frost heaving. The dewatering measures, which served to lower the water table and thus limit the water supply for ice segregation, are also suggested as important implement in rainy valley regions with ground high water tables. The installation of an anti-frost fill layer and drainage measures are effective and economical techniques to mitigate frost heaving and settlement of infrastructure in cold mountain regions.

This paper summarizes the results of probe drilling carried out ahead of TBMs in two difficult tunneling projects in Turkey. The tunnels have completely different geological characteristics which necessitated two different methods of data analysis. Melen Water Tunnel was excavated under Istanbul Bosphorus within sedimentary rocks which are cut frequently by andesitic dykes, fracturing the surrounding rocks and creating a potential risk for water ingress into the tunnel. At the beginning of Melen Project, pioneering probe drillings with petrographic analysis and strength tests were performed on samples collected from TBM muck. This analysis allowed identifying some critical normalized probe drilling rate values for predicting potential weak zones created by andesitic dykes. These studies gave a sound basis for further interpretation of TBM and geologic data for the same tunnel. The second set of probe drilling analysis was from Kargi Tunnel. The North Anatolian Fault highly affected the tunnel excavation by fractured rock formations. Although the change in normalized probe drilling data was a good indicator of fractured zones, the diversity of rock formations made it difficult to interpret the data.

Tunnelling in difficult and challenging conditions such as soft soils in urban areas is increasing. In this condition, it is important to minimise the possible negative effect of the tunnel excavation, such as settlement or, in the worst case, collapses. To achieve this result, earth pressure balance machines are commonly used. One of the key parameters that must be considered for an optimal management of the EPB-TBM excavation is soil conditioning since the excavated muck must properly transmit the pressure to the tunnel face. Soil conditioning is also necessary to reduce the effect of the problems, such as clogging in clay layers, that can occur during the excavation and that can affect the performance of the tools and of the entire tunnelling process. For this reason, in the last decade, much research has been carried out to understand how to deal with and reduce the effects of clogging and stickiness, using different conditioning additives. These studies have proposed several different test procedures to evaluate the effect of the conditioning on the adhesion of the soil on the metallic parts of the machines. The present research has been carried out with the aim of proposing a new approach and new devices to study clay conditioning with laboratory tests, and the results of many tests carried out with the proposed device are presented and discussed.

Assessment of management-induced changes in soil quality is important for sustaining crop yield. The purpose of conducting on-farm field research is to come up with fact-based answers to farming’s challenging questions and this type of research targets “real-world” data. However, research information on impacts of tillage on organic (muck) soils is scanty, and underlying processes of management-induced changes in soil characteristics are poorly understood. In addition, data are scarce on impacts of immediate short-term tillage on historically no-tilled mineral soils. Thus, the objectives of this research are to evaluate impacts of (1) long-term conventional tillage (CT) on organic or muck (Mc) soil compared to non-cropped no-till (NT) condition and (2) short-term CT on mineral (CrB) soil, which has been under NT management under corn. All monitored soil properties were significantly affected by soil type. Compared to CrB, Mc had 6.4 and 5 times higher soil organic carbon (SOC) and nitrogen (N) concentrations, respectively for all sampling depths. Long-term tillage had no impact on Mc probably due to its porous nature, weak structure and high organic matter content. In the mineral soil, short-term CT significantly affected bulk density (BD), water-stable aggregates (WSA), and available water capacity (AWC), especially, in the surface (0–10 cm) layer. The BD was reduced by CT for CrB by up to 14 % (NT 1.6 Mg m−3), compared to NT. Residue incorporation in the plow layer under CT (~20 cm) may have increased aggregation by up to 19 % (70–83 %) and SOC by up to 15 % (2–2.3 %) in CrB compared with that under NT (total aggregation 70 %, SOC 2 %). The data of this study demonstrate that (1) selected muck soil had significantly improved soil properties (higher WSA, AWC, SOC and N, and lower BD and penetration resistance) than those of the studied mineral soil, (2) long-term tillage did not affect the properties of the native muck soil, and (3) surface layer of the long-term no-tilled mineral soil was significantly affected by introduction of only 1 year of CT management.

As the use of mechanical excavation in tunneling and mining activities expands, so has the use of disc cutters in various ground conditions. The impact of moisture content on rock behavior and rock excavation by disc cutters is examined in this study. This was done through a series of full-scale cutting tests using a 292 mm (11.5 in.) disc cutter in a moderate strength sandstone. The muck from the cutting tests was used to determine coarseness index (CI) and absolute size constant (x′). x′ was calculated using Rosin–Rammler distribution (or Weibull) curve, a statistical technique to look at the fragmented rock products. This approach is very popular among the mineral-processing professionals for the evaluation of the particle sizes of the comminution products. x′ and CI show a reasonable correlation with the specific energy of cutting and production rate. Both of these indicators were found to be dependent on the cut spacing and the interaction between the adjacent cuts, as anticipated. This paper explains the background information on this topic, reviews the laboratory testing, and offers analysis of the results of grain size distribution and its relationship with specific energy and cutting geometry. It should be noted that the experimental program was limited to only one rock type and additional testing on the other rock types is required to expand the results of the current study.

Skin-set is a necessary prerequisite for potato storability, but there is little published information on the effect of cultural conditions on the development of skin-set. The phellogen layer acts as a lateral meristem for the peri- derm and while active, fracture of its thin radial walls leads directly to skinning injury during harvest and handling into storage. During maturation of the periderm, these radial walls thicken. Red-skinned cultivars are often grown in muck soils in Wisconsin to improve skin condition and color. We tested skin-set and phellogen radial wall thickness for 'Red Norland' tubers grown on either loamy sand or muck soils in central Wisconsin. Skin-set varied between years and soil types, but there was no consistent effect of soil type on skin-set. Phellogen radial walls in Red Norland tubers doubled in thickness between bulking and vine-kill, but did not change in the three week period following vine- kill even when skin-set improved. Physiological processes other than cell wall thickening must be responsible skin-set during the three weeks following vine death.

The re-use of rock as an industrial material requires more treatments than those foreseen for the reuse of muck as an aggregate for concrete and for road construction. The treatments always start with comminution, which has the goal of liberating the rock-forming minerals. Liberation is achieved with the appearance of grains which are composed of only one mineral. The subsequent treatment steps are based on the physical–mechanical–chemical properties of the different minerals, that is, density, magnetic susceptibility, wettability etc. Magnetic separation and flotation, the two techniques examined in this research, are the two most common techniques used in industrial mineral production plants. The mucks that were analysed are from the Omegna and Brennero tunnels, both of which are granitic rocks with different textures. From the analysis and comparison of the preliminary treatment results, it has been possible to optimise the treatment method. Petrographic, mineralogic and firing tests have been conducted to evaluate the obtained results. High-gradient magnetic separation (HGMS) on defined grain sizes appears to be suitable to obtain a product with a high feldspar–quartz content which could be used in the ceramic field.

Prediction models for exchangeable soil lead, published earlier in this journal (Andra et al. 2010a), were developed using a suite of native lead (Pb) paint-contaminated residential soils from two US cities heavily populated with homes constructed prior to Pb ban in paints. In this study, we tested the feasibility and practical applications of these prediction models for developing a phytoremediation design using vetiver grass (Vetiveria zizanioides), a Pb-tolerant plant. The models were used to estimate the exchangeable fraction of Pb available for vetiver uptake in four lead-spiked soil types, both acidic and alkaline, with varying physico-chemical properties and that are different from those used to build the prediction models. Results indicate a strong correlation for predictable exchangeable Pb with the observed fraction and as well with total Pb accumulated by vetiver grass grown in these soils. The correlation coefficient for the predicted vs. observed exchangeable Pb with p < 0.001 was 0.999, 0.996, 0.949, and 0.998 in the Immokalee, Millhopper, Pahokee Muck, and Tobosa soil type, respectively. Similarly, the correlation coefficient for the predicted exchangeable Pb vs. accumulated Pb in vetiver grass with p < 0.001 was 0.948, 0.983, 0.929, and 0.969 for each soil type, respectively. This study suggests that the success of a phytoremediation design could be assessed upfront by predicting the exchangeable Pb fraction in a given soil type based on its properties. This helps in modifying the soil conditions to enhance phytoextraction of Pb from contaminated soils.

The muck soils of the north shore of Lake Apopka, near Orlando, Florida, USA are high in organic matter, inorganic nutrients, and water content. Ideally suited for agriculture, these soils have been exposed to a wide variety of agrochemicals. Some of the more recalcitrant organochlorine pesticides, such as DDT and its degradation products DDD and DDE, have persisted in the soil for over 30 years. Using the extracellular enzymes from wood rot fungi, it was demonstrated that it is possible to substantially reduce the amount of the o,p′ and p,p′ isomers of DDT, DDD, and DDE in this soil by more than 60% in 3 weeks. A fungal species with 99% DNA homology to Nectria mariannaeae was isolated from this muck soil and identified by nucleotide sequencing. When grown under nitrogen-limited conditions, this Nectria sp. has been shown to be comparable to Phanerochaete chrysosporium (ATCC 24725) in producing extracellular factors (or agents) that are capable of degrading these recalcitrant chlorinated chemicals.

Peats consist of the partly decomposed remains of vegetation, which have accumulated in waterlogged areas. They are often unsuitable for supporting structures of any kind due to their high water content, high compressibility, low shear strength and high degree of spatial variability. The paper reports a preliminary study on peats from industrial sites in the city of Kayseri, Turkey. The soils in the study area are classified as peat to muck. The peats are fibrous at shallow depth and become amorphous as they extend to some 8 m depth. The ranges of geo-engineering properties are generally consistent with those reported in the literature, with some variation due to their higher mineral soil contents. The behavior of the peats is essentially frictional, with high friction and relatively small cohesion. The direct shear tests yielded higher shear strengths than those from the triaxial tests, due to the fact that the peat specimens used in the direct shear tests were rich in fibers and mineral soils. Back analysis of the settlement of heavy rolls of metal wires laid on the peat generally confirmed the consolidation properties of the soil determined in laboratory.

This paper reports a study of vacuum dewatering using horizontal geosynthetic drainage blankets as a more economical and effective method of reclamation using layers of dredged material. Laboratory tests were carried out on samples from two different sites in eastern China, Qingdao City and Lianyungang City. The study showed that the method is feasible and results in a significant time saving as the construction of the dyke, dredging of the fill and consolidation can be done in a successive process. Using geosynthetics as the drainage material allows vacuum dewatering in areas where sand is lacking. The strength and stability of the muck is also enhanced by the placement of horizontal geosynthetic drainage blankets.

The size distribution of a muck pile depends not on only the blasting standard but also on the mechanical properties, joint system, and crack density of the rock mass. As, the cracks in the rock masses are especially heavily developed at the limestone quarries in Japan, they, along with the joints, have a large impact on the effects of blasting, such as the size of the muck pile. Therefore, if the joint system and/or crack density in a rock mass can be determined and quantitatively evaluated, the blasting operation can be conducted more effectively, efficiently and safely. However, guidelines for designing appropriate blasting standards based on the rock mass conditions have not yet been scientifically developed. Therefore, blasting tests were conducted on different mines and faces, under different geological conditions and blasting standards, in order to determine the impacts of each factor on the effects of blasting. Summarized the results of a series of blasting tests and described the impacts of geological conditions on the size of the muck pile produced by blast.

Cranberry agriculture is a major land use in parts of the New Jersey Pinelands, USA. We compared the composition of genus-level macroinvertebrate assemblages collected from three habitats (muck, vegetated muck, and woody debris) in 12 New Jersey Pinelands blackwater streams draining forest, abandoned-cranberry bogs, and active-cranberry bogs and evaluated whether variations in macroinvertebrate assemblages were related to differences in land uses within the associated drainage basins. All 12 streams were relatively slow moving and acidic, with low conductance values and dissolved-oxygen concentrations. Muck was the dominant substrate at most stream sites. Many of the taxa that we encountered are adapted to lentic habitats, slow-moving lotic habitats, or low-oxygen environments. Macroinvertebrate composition differed significantly between the active-cranberry streams and the other two stream types and was associated with a complex environmental gradient represented by variations in dissolved oxygen, temperature, specific conductance, stream width, and woody debris. Overall, the effect of stream type appeared to overshadow that of the three different habitats. Although we cannot conclude that subtle between-site differences in dissolved oxygen were responsible for variations in community composition, many of the genera associated with the forest and abandoned-bog/active-cranberry ends of the community gradient are reported to have contrasting tolerances to low-oxygen levels. The relationship between reduced canopy cover and both lower woody-debris cover and higher stream temperatures, which can influence dissolved-oxygen levels, was most likely related to forest-canopy removal associated with historic- and active-cranberry agriculture.

On February 6, 1994, a large debris flow developed because of intense rains in a 800-m-high mountain range called Serra do Cubatao, the local name for the Serra do Mar, located along the coast of the state of Sao Paulo, Brazil. It affected the Presidente Bernardes Refinery, owned by Petrobras, in Cubatao. The damages amounted to about US $40 million because of the muck cleaning, repairs, and 3-week interruption of the operations. This prompted Petrobras to conduct studies, carried out by the authors, to develop protection works, which were done at a cost of approximately US $12 million. The paper describes the studies conducted on debris flow mechanics. A new criteria to define rainfall intensities that trigger debris flows is presented, as well as a correlation of slipped area with soil porosity and rain intensity. Also presented are (a) an actual grain size distribution of a deposited material, determined by laboratory and a large-scale field test, and (b) the size distribution of large boulders along the river bed. Based on theory, empirical experience and back-analysis of the events, the main parameters as the front velocity, the peak discharge and the volume of the transported sediments were determined in a rational basis for the design of the protection works. Finally, the paper describes the set of the protection works built, emphasizing their concept and function. They also included some low-cost innovative works.

The objective of this work is to assess the concentrations of three factions of air particles (settable particles, TSP and PM10) and the levels of several toxic elements in a clay atomisation industry through aerosol sampling at several points inside an industrial plant. Mechanical activities, which produce diffuse emissions, are the main process of discharge of particles in both indoor and outdoor workplace environments in the atomisation plant. The levels of As, Cd, Pb, Zn, Ba and Ni increase in the zones with higher concentrations of particles and lower ventilation. The concentrations of As and F are not influenced by the recycling processes. The levels of Cd and Pb do not show great enrichment in air particles collected inside the atomisation plant although the content of both elements is associated with ceramic muck recycling. Finally, the content of B in waste water is mainly transferred in gaseous phase to the atmosphere during the process of drying by atomisation.

A decrease in water level in areas of marsh accumulation initiates the process of peat weathering, known as the process of muck formation. This process is strictly connected with the disintegration of peats and results in the formation of sediment characterised by different physical, chemical and mechanical properties. Compared with the peats from which they originate, mucks are characterised by lower hydrophilous properties, higher sorption capacity, lower porosity, lower plasticity and lower shrinkage and compressibility. Due to these properties, a muck horizon can act as an isolation barrier against industrial and agricultural waste and hence is advantageous for environment protection. In addition, mucks have much more favourable physical and mechanical parameters than the peats from which they were formed.

To evaluate muck sediments as a potential soil amendment, total and Mehlich III-extractable concentrations of Cd, Cu, Cr, Ni, Pb, Zn, and Co in 59 muck sediment samples from the St. Lucie Estuary were analyzed. A seven-step chemical fractionation procedure was used to assess the potential mobility of heavy metals. Except for Cd, the average total concentrations of the metals are lower than the reported average concentrations of these elements in municipal composts in the U.S.A. The concentrations were also below critical levels for the safe use of wastes and byproducts in agriculture, as established by the United States Environmental Protection Agency. The Cd, Cu, Cr, Ni, Pb, Zn and Co in the sediments were predominantly associated with silicate minerals in the residual form. Most metals in the muck sediments occur predominantly in weakly mobile or nonbioavailable forms. Use of mucks in neutral pH upland soils should not pose any significant hazards or risk to the environment. However, Cd, Cu, Cr, Ni, Pb, Zn, and Co, especially Zn, Cu, and Pb, could be more readily released from the muck sediments under acidic soil conditions.

In response to the recent focus by the U.S. Environmental Protection Agency on bioassessment of lakes, a multimetric index was developed for New Jersey lakes and reservoirs using benthic macroinvertebrates. Benthic samples were collected from reference and impaired lakes with muck and intermediate sediments in central and northern New Jersey during summer 1997. We used a stepwise process to evaluate properties of candidate metrics and selected five for the Lake Macroinvertebrate Integrity Index (LMII): Hilsenhoff Biotic Index (HBI), percent chironomid individuals, percent collector-gatherer taxa, percent oligochaetes/leeches, and number of Diptera taxa. We scored metrics as the fraction of the best expected value (based on all sites) achieved at a site and summed them into the LMII. Evaluation of the LMII showed that it discriminated well between reference and impaired lakes and was strongly related to several potential stressors. Chemical and physical gradients distinguished between reference and impaired lakes, and the LMII summarized these gradients well. The LMII corresponded strongly with land use, but some lakes with more urban land use still achieved high scores. Based on a power analysis, the ability of the LMII to detect differences in condition was sensitive to the number of samples from each lake.

The potential of entomopathogenic nematodes as biologicalcontrol agents for carrot weevil (Listronotus oregonensis) was evaluated throughboth laboratory and field experiments. In thelaboratory, Steinernema carpocapsae, S. riobrave, S. feltiae, Heterorhabditis megidis, H. bacteriophora, and a control (water only) werecompared in sand and muck soil against adults,and in sand against larvae. All nematodespecies produced high levels of larvalmortality. S. carpocapsae producedsignificantly greater adult mortality in sandthan other species or the untreated control. H. bacteriophora caused low adultmortality in sand, but the greatest adultmortality among treatments in a similar testthat used muck soil; S. carpocapsae wasranked second on muck soil. Other speciesconsistently produced intermediate (H.megidis and S. riobrave) or low (S.feltiae) levels of mortality on bothsubstrates. In the field, we compared theeffect of early season vs. late seasonapplications of H. bacteriophora or S. carpocapsae on carrot weevil mortality andparsley survival and yield. Significantdifferences among treatments in plant survivaland yield were not found; however treatmentsinvolving H. bacteriophora had higherplant survival than other treatments. Earlierapplication of this species was associated withhigher plant survival. S. carpocapsaetreatments had similar plant survival to thecontrol. Mortality of larvae and combinedstages of carrot weevil was significantlygreater at 1 week following H.bacteriophora application than for othertreatments. H. bacteriophora also showedgreater persistence than S. carpocapsaein treated plots. We conclude that H.bacteriophora is a good candidate for furtherevaluation as a biological control agentagainst carrot weevil on muck soils in theGreat Lakes region.

Biochar is an organic carbon (OC) and plant nutrient-rich substance that may be an ideal amendment for bolstering soil organic matter and nutrient contents. Two biochars were produced by pyrolysis at 350 °C from pine chips (Pinus taeda) and swine manure solids (Sus scrofa domesticus). The biochar total elemental composition was quantified using inductively coupled plasma spectrometer and their surface chemical composition examined using a combination of scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). The biochars were mixed into triplicate pots containing Lauderhill muck (Euic, hyperthermic Lithic Haplosaprist) at 0, 2.5, 5, and 10 % (dry mass). Four simulated water infiltration events were conducted during the 124-day incubation to assess the potential alteration in the leaching potential of soluble soil nutrients. At termination, the muck’s fertility characteristics were assessed, and dissolved cations were measured in water leachates. Neither biochars significantly increased the muck’s OC contents. Swine manure biochar contained higher K, Mg, Na, and P concentrations, and these differences were observable in SEM and EDS as differing amounts of surface-precipitated Mg and K salts. Correspondingly, swine manure biochar at all three applications rates significantly increased Mehlich 1-s K, P, Mg, and Na concentrations. Pine chip biochar only improved the Mehlich 1-extractable K concentration but did reduce soluble P concentrations. Water leachates from swine manure biochar treated wetland soil contained significantly higher soluble P concentrations that could create water quality issue in downstream ecosystems.

The interaction between plant growth and nutrient availability is an important aspect of vegetation dynamics in wetlands. In this study, seedlings of Typha domingensis were used to assay the nutrient availability of fire-disturbed Florida Everglades soils. Seedlings were planted in soils that had been naturally muck- (MB), surface- (SB), or non-burned (NB) and that showed significant differences in concentrations of inorganic: total phosphorus according to fire severity. After two months of growth, plant height, number of leaves, culm diameter, number of rhizomes, length of rhizomes, live leaf biomass, and above-and below-ground biomass were greatest in MB seedlings. In addition, root architecture and biomass allocation were influenced by soil type. Seedlings from NB and SB soils developed thinner roots with numerous root hairs and had higher percentages of below-ground biomass. In contrast, seedlings grown in muck-burned soils developed large rhizomes in addition to thicker, hairless roots while allocating proportionally more biomass to aboveground parts. Tissue nutrient analyses showed that both experimental and field-harvested plants grown in MB soils contained significantly more phosphorus than plants from SB or NB soils. Typha domingensis has displaced plant communities in areas of the Everglades that receive nutrient-enriched agricultural runoff. However, this study suggests that establishment and expansion of this species also may occur in overdrained regions of the Everglades where muck fires are a frequent occurrence. In addition to creating an opening in the landscape, muck fires increase the bioavailability of soil phosphorus, thus providing a competitive advantage for T. domingensis.

The hydric soil definition and hydric soil criteria are often insufficient for use in field identification/delineation of hydric soils. This paper traces the experiences soil scientists and other wetland scientists had in Florida to properly identify, understand, and use hydric soil indicators to identify those soils that fit both the hydric soil definition and the hydric soil criteria. The hydric soil indicators that properly identify soils that fit the definition and criteria in Florida are as follows: hydrogen sulfide, organic bodies, stratified layers, muck, mucky texture, dark surface, stripped matrix, redox concentrations, gleyed matrix, depleted matrix, iron manganese masses, umbric epipedon, thick mollic epipedon, or marl. Exact thicknesses, depths, percentages, and colors that are required for each of the hydric soil indicators have been developed. Because of the knowledge gained from intense observations of morphological features in soils for hydric soil determinations scientists were able to transfer this technological ability to include the estimation of seasonal high water tables for all soils in Florida.

Pauly, I)., P. Muck, J. Mendo & I. Tsukayama (ed.) 1989. The Peruvian upwelling ecosystem: dynamics and interactions. Instituto de1 Mar de1 Peru (IMARPE), Callao, Peru, Deutsche Gesellschaft fur technische Zusammenarbeit (GTZ), GmbH, Eschborn, Federal Republic of Germany and International Centre for Living Aquatic Resources Management, Manila, Philippines. 438 pp. (U.S.) $15.00 (surface), $27.00 (airmail) softbound.

Human activity over the past century has caused large-scale environmental pollution. By characterizing bacteria indigenous to these polluted niches, microbiologists can identify mechanisms by which bacteria degrade contaminants, either to detoxify their habitat or for use as food and energy sources. Detailed analyses of the completed genomes of these degraders have produced many insights into their biology.

A fireball that landed in the Canadian Yukon has yielded meteorite fragments that are proving difficult to classify — could they be the most primitive samples to have been found on Earth so far?

When the rate of movement and the persistence of aldicarb in 4 types of soils were investigated in laboratory and field studies some leaching was detected in coarse sand; however, leaching was quite limited in clay loam and muck soils. These data indicated that aldicarb degraded quite rapidly in the selected soils and most of the applied radioactivity volatilized from these soil columns as 14CO2. The evolution of 14CO2 from the treated soil suggested severe degradation of the aldicarb molecule and consequently provided indirect evidence against the accumulation of significant quantities of toxic metabolites in the soil types evaluated. Under field conditions this toxicant appeared to have a half-life of about 7 days in loam soil.

Investigations of hydraulic fills of underwater soil foundations between the bottom of the section and base of the trench were carried out when constructing the first sunken-tube vehicular tunnel in USSR. These investigations established that the stream of muck issuing from the pipeline underwater expands and its velocity decreases with distance. The rectilinear rays including an angle of about 30 degrees are the limits of expansion of the stream. The stream of muck loses its transporting capacity with distance and soil particles settle within the spread, forming a portion of the foundation under the bottom of the immersed tunnel section. Continuous contact of the foundation surface with the bottom of the section is achieved by joining one portion to another by moving the pipelines under the sections, swiveling them through an angle of 30-45 degrees.

Mercury concentrations in various horizons of British Columbia soils were determined to estimate natural background levels in soils from various geographical areas of the province. Highly enriched concentrations near the Pinchi Lake cinnibar deposit declined to background levels ranging from 10 to 310 ppb Hg in the district. In six other regions, concentrations in surface mineral horizons averaged 85 ppb and ranged to 490 ppb but surface horizons of peaty muck soils and those predominated by vegetative litter contained 164 ppb Hg on the average and as much as 741 ppb. Concentrations in subsurface horizons were lower than at the surface. A significant relationship between Hg concentration and organic matter content was observed. Comparison with soils from outside British Columbia indicated its location within a generalized mercuriferous belt accounted for the relatively high concentrations observed.

Oxytetracycline-HCI (OTC) concentrations were measured in citrus leaves, fruit, and soil after applying OTC to soil as a drench. OTC was detected sporadically in low concentrations in leaves only during the first day after OTC applications and was not detected in fruit flavedo. Even after repeated drenches, OTC was not detected below 8 in. in the soil profile. Furthermore, OTC remained highly active in soil for at least 40 days and could still be detected in low concentrations one and a half years after the last OTC drench application. Adsorption of OTC varied with different soil types. Sandy soil (99.1% sand) had relatively little OTC adsorption capacity compared to less sandy soils (92–94% sand). OTC was inactivated in organic muck soil.

High specific activity(14)C-labeled glucose, succinate, acetate, salicylate, and amino acids were used to examine carbon metabolism by the microbial community of Pahokee muck (aLithic medisaprist), a drained, cultivated soil of the Florida Everglades. Variations in carbon oxidation were observed from the end of the wet season through the dry season in a fallow (bare) field. Evolution of(14)CO2 varied with the substrate added and time. Calculation of(14)CO2 evolution for each substrate as a proportion of total respiration of the microbial community which was measured by succinate oxidation (relative oxidation) allowed for determination of the proportion of metabolic activity contributed by the oxidation of each carbon source. Except for the May sample when an approximate 30% decline in relative salicylate oxidation activity was observed, the proportion of total catabolic activity contributed by salicylate oxidation and acetate degradation was constant with time. Relative oxidation of glucose and amino acids ranged from 0.12 to 0.52 and 0.10 to 0.23, respectively. At two times during the dry season, the effect of depth of soil and crop on the carbon oxidation was examined. Relative acetate and amino acid oxidation were constant with depth whereas statistically significant variation was observed in glucose and salicylate oxidation. Generally, with the latter substrates, the activity declined with increased soil depth. Greatest effect of crop on these metabolic activities was noted with oxidation of salicylate in soils from a St. Augustinegrass [Stenatophrum secundatum (Walt.) Kuntz] pasture. In these soils, oxidation of salicylate was nearly double that of the fallow field or of soil planted with sugarcane (Saccharum sp.).

This paper reports laboratory experiments on dinitrogen fixation and denitrification for two small quaking fens (discharge fen and recharge fen) using the acetylene reduction assay and the acetylene inhibition technique, respectively. Nitrogenase activity was detected in peat muck and associated with Alnus glutinosa saplings throughout the study period (May–October 1987), whereas no activity was observed with Sphagnum species. The annual amount of dinitrogen fixed was estimated at 2.1 and 12.7 kg N/ha/y for the recharge fen and the discharge fen, respectively. Denitrification at ambient nitrate levels (0.1 ppm NO3) was absent in the discharge fen and very low in the recharge fen (0.1 μg N/g/d, or 0.3 kg N/ha/y). In nitrate-amended soil samples denitrification rates were 2 to 3 orders of magnitude higher. It is argued that in situ denitrification rates in the fens studied will depend almost entirely on the nitrate supply by precipitation. Denitrification rates associated with precipitation are estimated at 1.1 kg N/ha/y for both fens.

Nine herbicide treatments were applied to potatoes grown at three locations in each of 3 years. The locations were characterized by widely different soil types—silty clay loam, sandy loam, and muck—and by differences in rainfall and temperatures during the growing season. None of the herbicide treatments applied pre-emergence gave adequate weed control at all locations and/or in all years. EPTC at 6 lb per acre (6.72 kg/ha) gave excellent weed control on both mineral soils but not on muck. Metabromuron at 4 lb per acre (4.48 kg/ha gave excellent weed control only on the low organic matter sandy loam. Propachlor at 6 lb. (6.72 kg/ha) and 2 lb amiben plus 3 lb propachlor (2.24 plus 3.36 kg/ha) gave variable control. Four herbicides: 1 lb paraquat (1.12 kg/ha), 2 lb linuron (2.24 kg/ha), 6 lb dinoseb (6.72 kg/ha) and 6 lb dinoseb plus 2.25 dalapon (6.72 plus 2.52 kg/ha) applied at potato plant emergence, when weeds were in the 2–6 leaf stage, also gave variable control but as a group generally gave better control than the pre-emergence herbicides, particularly on muck soil. The effectiveness of herbicides applied at potato plant emergence was less affected by soil type than those applied pre-emergence but was affected by the degree of weed emergence. On muck soil, weeds generally emerged well before “at emergence” herbicide treatments were applied. Tuber yields were not directly affected by the herbicides, but were reduced where weed control was inadequate. Tuber specific gravity and chip color were unaffected by the herbicides.

The Katahdin potato is resistant to mild mosaic but not to spindle tuber or leaf roll. It is a high-yielding variety, producing tubers of excellent shape, with shallow eyes and desirable cooking quality. The vines mature late but the tubers apparently set rather early. Observations have indicated that it is probably well adapted to muck and peat soils. It is not believed to be well suited to regions that have summer droughts. If favorable results are obtained in 1931 a more extensive introduction will be made in 1932, provided it seems advisable to the agricultural experiment stations in the states in which the tests have been made.

On Rhum, Eigg, Canna and Muck Tertiary volcanics rest upon a Mesozoic or Pre-Mesozoic basement. Aphyric, olivine-phyric, and plagioclase-phyric basalts are recognized. The aphyric basalts are mildly alkaline or transitional types with either a few percent normative nepheline or normative hypersthene. They have anomalously low concentrations of Rb, Sr and K2O compared to Tertiary tholeiites from the same province.