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Ground penetrating radar (GPR) is an efficient method for soil moisture mapping at the field scale, bridging the scale gap between small-scale invasive sensors and large-scale remote sensing instruments. Nevertheless, commonly-used GPR approaches for soil moisture characterization suffer from several limitations and the determination of the uncertainties in GPR soil moisture sensing has been poorly addressed. Herein, we used a proximal GPR method based on full-waveform inversion of ultra-wideband radar data for mapping soil moisture and we evaluated uncertainties in the soil moisture maps by three methods. First, GPR-derived soil moisture uncertainties were computed from GPR data inversions, according to measurements and modeling errors, and to the sensitivity of the electromagnetic model to soil moisture. Second, the repeatability of soil moisture mapping was evaluated. Third, GPR-derived soil moisture was compared with ground-truth measurements (soil core sampling). The proposed GPR method appeared to be highly precise and accurate, with a spatially averaged GPR inversion uncertainty of 0.0039 m3 m-3, a repetition uncertainty of 0.0169 m3 m-3, and an uncertainty of 0.0233 m3 m-3 when compared with ground-truth measurements. These uncertainties were mapped and appeared to be related to some local model inadequacies and to small-scale variability of soil moisture. In a soil moisture mapping framework, the interpolation was found to be the main source of the observed uncertainties. The proposed GPR method was proven to be largely reliable in terms of accuracy and precision and appeared to be highly efficient for soil moisture mapping at the field scale.

Two collections of Pauropoda (Myriapoda) from soil cores in high-country subalpine and alpine tussock grassland in New Zealand contained 757 specimens representing 11 species, eight of which are recognised as new to science, including two representing new genera. The following new taxa are described here by the first author: Ataktopauropus Scheller gen. n. for Ataktopauropus adaios Scheller sp. n., Decapauropus orestes Scheller sp. n., Decapauropus undulatus Scheller sp. n., Nesopauropus upsilon Scheller sp. n., Pauropus otagoensis Scheller sp. n., Pounamupauropus Scheller gen. n. for Pounamu- pauropus bartonae Scheller sp. n. and Stylopauropoides vesica Scheller sp. n. (all seven species in family Pauropodidae), and Borneopauropus neozelandicus Scheller sp. n. (family Brachypauropodidae). The genera Nesopauropus Scheller and Borneopauropus Scheller are reported from New Zealand for the first time.

Several methods are used for the extraction of soil solution. The objective of this study was to find out to what extent the different extraction methods yield complementary or equivalent information. Soil solutions were sampled once at 10 different forest sites in Germany, with 4 sampling points per site, using 5 different extraction methods. Concentrations of the major ions in the 1:2 extracts and the equilibrium soil-pore solutions (obtained from percolation of field-fresh soil cores) were generally lower than in desorption solutions, suction-cup solutions, and saturation extracts. Surprisingly, the latter three methods generally yielded equivalent results. However, possible systematic differences between these methods could have been masked by the high small-scale spatial variability within the sites.

Restoring historic lake-fringe wetlands is considered a favorable means of reducing lake phosphorus levels; however, it is unclear how various strategies for managing wetland connectivity influence phosphorus release. We investigated the relationships between temperature and soil characteristics of restored wetlands to identify management strategies that minimize external phosphorus loading to Upper Klamath and Agency Lakes. We flooded soil cores at various temperatures and analyzed them for several forms of phosphorus and other physical properties. We compared measures of microbial activity and physical characteristics of phosphorus fractions within the wetland soils to forms of phosphorus in water relevant to phosphorus-loading in the lakes. Greater release rates of total phosphorus occurred in summer temperature treatments for all study wetlands (average 31.81 to 240.61 mg/m2 /d), while release rates of soluble reactive phosphorus (average −15.9 to 62.19 mg/m2 /d) varied with temperature and soil characteristics. Wetlands with mineral soils and direct hydrologic connectivity to the lakes released the lowest concentrations of total phosphorus, while soluble reactive phosphorus release varied across management strategies and soil types. These differences can be explained by the dominant phosphorus processes associated with the hydrology and biogeochemistry of the individual sites, and temperature and potential for microbial activity at the timing of inundation. Our results provide evidence that directly connected wetlands may release less phosphorus than indirectly or mechanically connected wetlands, due to early timing of inundation and longer duration of inundation.

A change in environmental conditions may result in altered soil microbial communities in alpine grasslands but the extent and direction of the change is largely unknown. The aim of our study was to investigate (i) differences in soil microbial communities across an elevation gradient of (sub)alpine grassland soils in the Swiss Alps and (ii) the long term effect of translocation of soil cores from a higher to a lower elevation site. The translocation of undisturbed soil cores from a high alpine site (2525 m asl) to a subalpine site near the timberline (1895 m asl) induced an effective artificial warming of 3.3 degrees C. We hypothesized that after longer than a decade soil microbial community in translocated cores would differ from that at the original site but resemble the community at the new site. Results from soil phospholipid fatty acid (PLFA) analysis confirm significant differences in microbial communities between sites and a shift in total microbial biomass (TMB) and proportional distribution of structural groups in the translocated cores towards the lower elevation community. Patterns related to translocation were also observed as shifts in the fractional biomass of ectomycorrhizal and arbuscular fungi and in relative contents of several structural groups. Hence soil microbial community activity and diversity indicate a moderate shift towards new site conditions after 11 years and therefore our data suggest slow responses of microbial communities to environmental changes in alpine soils.

A különböző N-formák mozgását és transzformációját a talaj–növény–légkör rendszerben egymással összefüggő ciklusok határozzák meg. Az olyan mesterséges beavatkozások, mint például a műtrágyák és szerves trágyák intenzív felhasználása, döntő mértékben befolyásolják a N-körforgalmat, jelentősen terhelve ezzel a ciklusok érzékeny egyensúlyát. Annak érdekében, hogy a problémákat kezelni tudjuk, a N-ciklus talajban lejátszódó folyamatainak jobb megértése, a különböző folyamatok súlyának és érzékenységének megismerése szükséges, alapot teremtve ezzel egy racionálisabb és környezetkímélőbb trágyázási és tápanyag-utánpótlási gyakorlatnak. A N-ciklus matematikai modellezése kiváló lehetőséget nyújt az egyes részfolyamatok alaposabb felderítésére. A munka során egy korábban elvégzett kísérlet adatait használtuk fel. Az inkubációs talajoszlop kísérletet a Szent István Egyetem Kémia és Biokémia Tanszékén végezték 2000-ben. A felhasznált kísérlet mérési adataira nemlineáris regresszióval illesztettünk különböző rendű kémiai kinetikai egyenleteket az Origin 4.1-es adatelemző és grafikai szoftverrel. A munka eredményeként megállapítható, hogy a részfolyamatok modellezésekor a legtöbb esetben az elsőrendű kémiai kinetikai egyenlet eredményezte a legjobb matematikai közelítést.

Increasing atmospheric carbon dioxide and its feedbacks with global climate have sparked renewed interest in quantifying eco- system carbon (C) budgets, including quantifying belowground pools. Belowground nutrient budgets require accurate estimates of soil mass, coarse fragment content, and nutrient concentrations. It has long been thought that the most accurate measurement of soil mass and coarse fragment content has come from excavating quantitative soil pits. However, this methodology is labor intensive and time consuming. We propose that diamond-tipped rotary cores are an acceptable if not supe- rior alternative to quantitative soil pits for the measurement of soil mass, coarse fragment content, C and total nitrogen (N) concentrations. We tested the rotary core methodology against traditional quantitative pits at research sites in California, Nevada, and New York. We found that soil cores had 16% higher estimates of less than 2-mm soil mass than estimates obtained from quantitative pits. Conversely, soil cores had 8% lower estimates of coarse fragment mass compared with quantitative pits. There were no statistical differences in measured C or N con- centrations between the two methods. At the individual site level, dif- ferences in estimates for the two methods were more pronounced, but there was no consistent tendency for cores to overestimate or under- estimate a soil parameter when compared with quantitative pits.

Scientists estimate seed abundances to calculate seasonal carrying capacities and assess wetland management actions for waterfowl and other wildlife using soil core samples. We evaluated recovery of known quantities of moist-soil seeds from whole and subsampled experimental core samples containing 12 seed taxa representing small, medium, and large size classes. We recovered 86.3% (SE = 1.8) of all seeds added to experimental cores; 8.3% (SE = 1.2) of seeds were destroyed during the sieving process and 5.4% (SE = 1.2) were not recovered by observers. Recovery rates varied by seed size, but not seed quantity or disproportionate ratios of seed-size classes. Overall seed recovery rates were similar between subsampled ( = 81.2%, SE = 3.6) and whole—processed core samples ( = 86.3%, SE = 1.8). We used recovery rates to generate size-specific, taxon-specific, and constant correction factors and applied each to actual core sample data. Size-specific correction factors increased seed mass estimates in the...

17β-estradiol (E2) is a natural estrogenic hormone found in animal manure and urine, which may cause endocrine disruption in sensitive organisms. 17β-Estradiol has been widely detected in the environment, and animal agriculture may be an important source. The objectives of this study were to investigate the potential sources and/or spatial and temporal characteristics contributing to detections of E2 at the farm-scale. Soil cores, segmented into 0.15m increments, were taken down to the water table from four locations (three potential E2 sources and one control) at or around a swine (Sus scrofa domesticus) farm on five different dates between 2006 and 2007. Estradiol was quantified in the soil-water extracts using liquid chromatography-with tandem mass spectrometry (LC/MS/MS) analysis. Estradiol detections were widespread and found in 128 out of 345 extractions (37%). Concentrations ranged from 0 to 1910 ng L⁻¹ (porewater equivalents). A location that received field application of manure had significantly lower E2 concentrations compared to other locations. Also, the spring 2007 E2 concentrations were significantly higher than all other sample dates, perhaps related to climatic and hydrological events. Results suggested E2 was not directly related to manure sources, but was widespread in this environment. Where E2 was detected, highest concentrations favored the upper profile, while the greatest frequency of detections was in the lower profile and near the water table. Detections of E2 were associated with high organic mater contents in the upper profile and high sand contents in the lower profile. The study suggests that E2 is widespread in some soil environments, raising questions as to the source and mechanisms that facilitate its transport and mobility.

We investigate the flow rate dependency of solute transport within an undisturbed monolithic soil core, collected in an Inceptisol. Through a series of nine controlled steady-state solute breakthrough experiments, flow rate dependency of solute transport was elucidated using the general transfer function (GTF) modeling theory. We first observed that the apparent dispersion coefficient increases with depth and flow rate. We also observed that the flow regime is rather a convective–dispersive (CD) process at low flow rates and a stochastic–convective (SC) process at high flow rates. At intermediate flow rates, the flow regime could not be described with either CD or SC processes. To better understand the mechanisms of altering flow regime at intermediate flow rates, a dye tracer experiment was conducted. Results show that preferential flow is initiated at intermediate flow rates. We hypothesize that the mixing of solutes between stream tubes decreases when flow rate increases, due to the decrease of the tortuosity of solute flow paths and the initiation of preferential flow through macropores.

It was previously hypothesised that reduction in the soil will set in at 70% water saturation (S0.7). This study aimed to determine the effect of different degrees and durations of water saturation on reduction in soil. Reduction was measured as a decrease in soil oxidisability (pe) and an increase in soluble iron (Fe2+). A yellow brown apedal B horizon from profile 234 in the Weatherley catchment was used in this study. Soil cores were packed to a bulk density of 1.6 Mg m−3 and saturated to S0.6 (60% of the pores saturated with water), S0.7 (70% of the pores saturated with water), S0.8 (80% of the pores saturated with water), and S0.9 (90% of the pores saturated with water). Analyses started three days after water saturation. Samples were analysed every 3.5 days for the first three months and then once a week for another month. The experiment was terminated after 121 days. There was a good correlation between an increase in degree of water saturation and pe (R2=0.95), Mn2+ (R2=0.99) and Fe2+ (R2=0.99) co...

This study investigated the degree to which human activities through urbanization influence heavy metal concentrations in a suburban landscape in Ankeny, IA. Residential areas from different years in nine time periods of development were identified from aerial photos. Soil cores were collected from the center of the front yard of 10 randomly selected homes. Cores were subdivided into 0- to 5-, 5- to 10-, and 10- to 20-cm increments from a composite of five cores. The soils were analyzed for organic C, pH, and total Cd, Co, Cr, Cu, Ni, Pb, and Zn. Results showed that organic C increased and pH decreased with time, and that there was a general decreasing trend in heavy metal concentrations from the pre-1939 period until 1983-1990, after which there was a sharp increase in the concentrations of most of the metals. The mean Cu concentration ranged from 21 mg kg(-1) for the pre-1939 time period of development to 14.9 mg kg(-1) for the recent period of development (2003-2005). Nickel concentrations increased significantly with depth with means of 21.3 mg kg(-1) at depth 0 to 5 cm, 22.5 mg kg(-1) at depth 5 to 10 cm, and 23.0 mg kg(-1) at depth 10 to 20 cm. The concentrations of heavy metals were significantly intercorrelated, except Zn, suggesting their coexistence as mineral constituents or common contamination source. The concentrations of Cu and Pb in some locations could be due to anthropogenic inputs or higher organic matter content in soils adjacent to older homes. There appears to have been a source that caused an increase in Cd, Cr, Co, Cu, Pb, and Ni concentrations in soil adjacent to homes built between 1983 and 1990.

Site 22LI504 is a predominantly Archaic period site in Lincoln County, Mississippi. One of its primary elements of interest is a single conical mound from which small-diameter cores revealed evidence of advanced pedogenesis. A radiocarbon sample from one soil core produced a date suggesting that the mound was Archaic in age (Fulmer 2001); however, it was unclear whether the sample came from within the mound or an underlying midden. In the spring of 2006, we excavated a 1-x-1-m unit in the mound to investigate this question. Diagnostic lithic artifacts, an advanced state of soil horizonation, and a lack of ceramics indicate that the mound is of Archaic period construction, with as many as five construction stages and artifact-rich features. We describe the soil profiles, features, and artifacts recovered from the mound, with comparisons to excavation units in an adjacent Archaic midden to show that there is no clear evidence for the mound being a functionally specific locus. We also present radioca...

This work presents indoor radon measurements in 42 dwellings in the city of Megalopolis, Southern Greece, located in the vicinity of 2 lignite-fired power plants and examines the effect of season, floor level and age of the dwellings on indoor radon concentration. The radon measurements have been carried out using the LR-115, type II and CR-39 alpha track detectors in “closed-can” geometry. The average annual indoor radon concentration (GM) was found to be 52 Bq m −3 , which is well below the recommended action level of the European Union. This value corresponds to an annual effective dose to the population of 1.3 ± 0.4 mSv. Season and age of the examined dwellings represent factors that affected significantly the indoor radon in Megalopolis, while the effect of floor level appeared to be not significant. Radium activity concentration values, measured by γ-ray spectrometry in 20 sub-samples of six soil cores (60–135 cm depth), collected from the surrounding area of the city, were found to be consistent with the Greek and world average values. Based on the results of this study, it is concluded that the effect of the lignite-fired power plants on indoor radon concentration in Megalopolis’ dwellings was not significant.

Capacitance probes (CP) based on responses to electromagnetic properties in soil are widely used for monitoring soil volumetric water content (θ v ), but proper calibration is necessary to obtain reliable results. The objectives of this study were to: (i) compare errors in evaluating θ v when using soil-specific equations as opposed to the manufacturer's default equation; (ii) compare the CP calibration equations obtained in the laboratory and in the field; and (iii) evaluate the accuracy of CP under field conditions using soil-specific equations as opposed to the manufacturer's default equation. Laboratory and field calibrations were conducted by fitting statistical relationships between readings from CP and θ v measured from soil cores. The accuracies of the obtained calibration equations were evaluated under field conditions during two irrigation cycles. In both calibration studies, the manufacturer's default equation consistently overcalculated θ v (RMSE > 0.044 m 3 m-3 ) , whereas custom CP calibration equations provided accurate θ v determinations (RMSE < 0.028 m 3 m -3 ). Even when θ v was overestimated, the manufacturer's default equation was able to reproduce θ v dynamics during irrigation. Therefore, if users are interested in relative differences in θ v , they may use the manufacturer's default equation. If absolute values are needed, however, soil-specific calibration is required. The accuracy of CP in monitoring θ v under field conditions was slightly better using the laboratory calibration equation (RMSE = 0.019 m 3 m -3 ) rather than the field calibration equation (RMSE = 0.023 m 3 m -3 ). The use of a laboratory calibration is recommended given that it is easily reproducible, facilitates work planning, and minimizes uncertainties.

The objective of the study was determination of the variability of morphometry and comparison of the morphological structure of the root system in winter cultivars of spelt. Four spelt cultivars were used in the study: Frankencorn, Oberkulmer Rotkorn, Schwabenkorn and Ostro. The material for the study originated from a field experiment. The roots were collected using the soil core method to the depth of 30 cm, from the rows and inter-rows, then the roots were separated using a semi-automatic hydropneumatic scrubber. The cleaned roots were manually separated and scanned, obtaining their digital images. Image analysis was performed using the Aphelion computer software. In order to characterize the root system of the spelt cultivars included in the study, values of the following indexes were determined: root dry mass (RDM), root length density (RLD), specific root length (SRL), mean root diameter (MD). Based on the obtained results it was determined that the RDM, MD and RLD indexes in all spelt cultivars attain the highest values in the row, at the depth 0–5 cm.The highest value of the RDM and MD indexes characterized the root system of the Ostro cultivar at the depth 0–5 cm. The Oberkulmerrotkorn spelt cultivar was distinguished among the tested objects by the highest value of the SRL index.

Soil water content is often determined using various permittivity sensors. The Hydra Probe reports both the real (e') and imaginary (e") components of complex permittivity (e*) and estimates electrical conductivity (σ'). Previously, a 12-wire probe was used with a vector network analyzer to determine e' and e" and σ' and σ" in undisturbed soil cores. The purpose of this study was to compare results from the Hydra Probe and the 12-wire probe for fluids as well as for soil samples taken from six locations, to better understand the interrelations of e', e", and σ' from the Hydra Probe. Undisturbed soil cores were collected from an Iowa prairie and adjacent soybean [Glycine max (L.) Merr.] field, an Iowa forest and adjacent soybean field, Idaho burned and unburned sites, Colorado grassland and dryland wheat (Triticum aestivum L.) sites, Ohio grassed areas, and Texas rangeland and an irrigated field. Because of their density, some of the Texas samples were sieved and repacked. The reported σ', e', and e" values of fluids were compared between the two measurement systems and with theoretical values. Because the theoretical values for soils are not known, the measured values were compared between systems. Both probes showed σ', e', and e" close to the theoretical values for fluids. In soils, we showed that an adjustment was needed in the calculated σ' from the Hydra Probe to account for dielectric relaxation. The soil σ' of the Hydra Probe matched σ' from the 12-wire probe better after the adjustment was made.

37 PBDE congeners were analyzed at six different depths in two soil cores taken from a typical electronic waste polluted area in South China. The PBDEs were congregated in the surface layer (0-5 cm) of soil cores and were 29 times in MK and 18 times in NW higher than the second lower layers (5-10 cm). As a whole, the concentrations of PBDEs were decreased with the soil depth increased in two cores. Lower brominated PBDE had higher penetrability than the deca-BDE in soil. The deca-BDE could be detected in deeper soil layers (15-20 cm in MK and 20-30 cm in NW) and the percentage of deca-BDE decreased with the increase of depth.

The purpose of this study was to investigate the effects of thinning on fine root biomass and vertical distribution. and litterfall amount in a 50 year old Pinus koraiensis plantation in Chuncheon, Kangwon Province. Fine root () in the site `OC_75`, thinning once in 1975, was 68% of those in the site `CON`, no thinning after planting, and in the site `TC_00`, thinning twice in 1975 and 2000. There were no significant differences of dead roots among treatments. Diameter roots were vertically decreased only in the TC_00 site. The litterfall was very similar between OC_75 () and TC_00 (), but the composition of litterfall was different: The proportion of leaves and branches was 80% and 13% in OC_75 and 56% and 36% in TC_00, respectively. Reduction of P. koraiensis density by thinning decreased leaf litter as well as fine roots of P. koraiensis, but increased fine roots production by neighboring understory plants offset the reduction of fine roots of P. koraiensis. We suggest that belowground as well as aboveground responses, including both over- and understory vegetation, should be considered to measure the responses of trees in thinned forest ecosystems.

ConservaƟ ve solute transport experiments were conducted at a fi eld plot and on an undisturbed soil core from the same site. The hydraulic and solute transport properƟ es were extensively characterized so that the data could be analyzed from a determinisƟ c perspecƟ ve. To invesƟ gate the infl uence of scale and conceptual model on solute transport in the relaƟ vely homogeneous upper soil profi le of the fi eld site, breakthrough curves that were collected at diff erent depths in the undisturbed column and in the fi eld experiments were compared and analyzed. The mobile-immobile model provided a physically realisƟ c descripƟ on of the column data that was largely independent of the transport distance, and upscaling from the undisturbed core to the fi eld plot was relaƟ vely successful. Mean and variance of the Br − travel Ɵ mes were controlled by plot-scale variability in soil water content and heterogeneity, which was overcome by averaging the concentraƟ on values from four locaƟ ons at the same depth and Ɵ me, and analyzing the Br − transport behavior as a one-dimensional process. Diff erences between the measured and simulated mass balances, average concentraƟ on, and the variaƟ ons in concentraƟ on were predicted reasonably well across depth and Ɵ me. Although predicƟ on of the exact concentraƟ on informaƟ on at a given point was not achieved, this study demonstrates that areaaverage Br − transport in a heterogeneous vadose zone can be determinisƟ cally quanƟ fi ed.

Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation. Diaphragm wallsoil-cap interaction was studied using a model test. It was observed that the distribution of soil resistance under the cap is not homogeneous. The soil resistance in the corner under the cap is larger than that in the border; and that in the center is the smallest. The distribution of soil resistance under the cap will be more uniform, if the sectional area of soil core is enlarged within a certain range. Due to the existence of cap, there is a “weakening effect” in inner shaft resistance of the upper wall segments, and there is “enhancement effect” in the lower wall segments and in toe resistance. The load shearing percentage of soil resistance under the cap is 10%–20%. It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.

Management practices, such as fire and mowing, can affect the distribution and quality of roots and soil C and N in grasslands. We examined long-term (13 years) effects of annual fire and mowing on fine (

The nature restoration of wetlands is strongly required as they have been severely altered. We focused on the drained lands, widely spread in the 20th century. It is important to study the diaspores of aquatic plants in the soil to grasp the regeneration potential of the drained lands. The purpose of this study was to reveal the vertical distribution of diaspores of aquatic plants in the soil of Oguraike and Yokoojinuma drained lands, where more than 50 years passed after the reclamation. The soil cores with the length of 50 cm were collected from nine locations. The cores were cut into five sections and studied on the germination ability of the diaspores in the soil under 0-cm and 5-cm depth of water. As a result, we found that the number of species and individuals exponentially decreased when depth of soil sampling became greater. Six endangered plant species were germinated in the experiment and the two among them were the species that could not be found on site at the locations of soil core samplings.

An experimental study to investigate the potential soil accumulation of the triazole fungicide difenoconazole in soil was carried out in northwestern Italy. The fungicide was applied to sugar beet for 4 years with three applications per year at a rate of 75 g ha−1 each, according to formulated product recommended use. Soil cores were collected each year before the first application, after each application and at harvest of the crop. The soil samples were then split into 0–10 and 10–40 cm depth layers, extracted and quantitatively analysed by gas chromatography for difenoconazole residues. The study evidenced that difenoconazole residues could be detected in the upper soil layer only, in quantities detectable after several applications (0.14 to 0.32 mg kg−1 after the third application) which then become undetectable the following year. It can be concluded, therefore, that difenoconazole does not accumulate in soil.

Determining atmospheric deposition rates of mercury and other contaminants using lake sediment cores requires a quantitative understanding of sediment focusing. Here we present a novel approach that solves mass-balance equations fortwo cores algebraicallyto estimate contaminant contributions to sediment from direct atmospheric fallout and from watershed and in-lake focusing. The model is applied to excess 210Pb and Hg in coresfrom Hobbs Lake, a high-altitude lake in Wyoming. Model results for excess 210Pb are consistent with estimates of fallout and focusing factors computed using excess 210Pb burdens in lake cores and soil cores from the watershed and model results for Hg fallout are consistent with fallout estimated using the soil-core-based 210Pb focusing factors. The lake cores indicate small increases in mercury deposition beginning in the late 1800s and large increases after 1940, with the maximum at the tops of the cores of 16-20 microg/m2 x year. These results suggest that global Hg emissions and possibly regional emissions in the western United States are affecting the north-central Rocky Mountains. Hg fallout estimates are generally consistent with fallout reported from an ice core from the nearby Upper Fremont Glacier, but with several notable differences. The model might not work for lakes with complex geometries and multiple sediment inputs, but for lakes with simple geometries, like Hobbs, it can provide a quantitative approach for evaluating sediment focusing and estimating contaminant fallout.

Prior research has shown a log-log correlation between ex situ air permeability (k a ) measured at a matric potential of -50 and -100 cm H 2 O and saturated hydraulic conductivity (K sat ) in agricultural soils. We examined the applicability of a previously established log k a vs. log K sat predictive relation in unburned and burned woodland-chaparral and coniferous soils. Specifically, we measured in situ k a in the field using the soil corer air permeameter (SCAP) and measured laboratory K sat on soil cores. To determine postfire soil physical changes, K sat was transformed into water permeability, k w. Then k a and k w were compared in unburned and burned soils. The median k a was lower and median k w was higher in burned than unburned woodland-chaparral soils. The median k a and k w were both lower in burned than unburned coniferous soils. Despite these effects, the 95% prediction interval of the predictive relation includes 80% of the burned soils and 83% of all desert soils. The RMSE values of the predicted log K sat and measured log K sat were 0.371, 0.552, 0.588, and 0.511 m d -1 for unburned and burned woodland-chaparral and unburned and burned coniferous soils, respectively. In comparison, the RMSE for the predicted and measured log K sat was 0.654 m d -1 for an agricultural data set. The overall RMSE for unburned and burned soils including the agricultural soils was 0.551 m d -1 . This suggests that the predictive relation is applicable for unburned and burned desert soils for in situ k a measurements.

S. S. Vyalov's's idea that microcrack development is the cause of the loosening of soils is used. Results of computational determination of the moment of initiation and development of microcracks in frozen sandy and cohesive soils in the beds of rigid cylindrical plates are presented. A comparison is made with data derived from experimental investigations. It is established by calculations that plastic shears and microcracks created by ultimate tensile stresses are the cause of widespread loosening and failure of sandy beds beneath plates.

This study describes soil horizon depth and fine root distribution in cores collected at two distances from the boles of Douglas-fir and ponderosa pine trees at a study site in a central Idaho forest. Concentration and content of fine roots extracted from soil cores were compared among species, soil horizons, tree size, and distance from bole. Approximately 80% of litter and humus samples contained no fine roots. The highest fine root content and concentrations of fine roots occurred in deep mineral soil for both species (1.24 g and 2.82 g/l for Douglas-fir and 0.98g and 2.24 g/l for ponderosa pine, respectively). No statistically significant differences were found in fine root content or concentration between species in any of the four soil horizons. Tree size was not a significant factor in fine root distribution in this study. Significant variables were horizon, distance from bole, and interactions among tree size, location of sample, and soil horizon. This study, which was part of a larger US Forest Service study to develop a predictive model of postfire tree mortality, provides baseline information that may be useful in predicting postfire damage to fine roots.

The ancient Maya have been accused of destroying their forests yet the Maya forest today is replete with economic value, and contemporary traditional Maya forest gardeners manage and maintain the dominant plant so f the forest for their economic values. Paleoenvironmental reconstructions of the Maya area have relied on the distribution of primarily wind borne pollen in ancient soil deposits, but the majority of these plants are pollinated biotically. An examination of the pollen syndromes of the dominant species of the Maya forest and the forest gardens demonstrates that only one of the dominant plants of the forest today appears in the pollen record of paleoenvironmental soil cores. In contrast, all the herbs and grasses of the high performance milpa, although dominated by maize, are in the pollen record. Rather than deforested, I suggest that the ancient Maya created a mosaic of field to forest, very little of which can be effectively defined in the palynological record.

There is a need to simultaneously preserve evidence of interactions between the biological community and soil structural properties of a soil in as near an intact (natural) state as possible. Three dehydration techniques were implemented and assessed for their ability to minimise disruption of both biological and physical properties of the same arable soil sample. Dehydration techniques applied until samples were at constant weight were i) air-drying at 20 °C (AD); ii) −80 °C freeze for 24 h, followed by freeze-drying (−80FD); and iii) liquid nitrogen snap freeze, followed by freeze-drying (LNFD) and were compared to a moist control. Physical structure was determined and quantifled in three dimensions using X-ray computed tomography and microbial phenotypic community composition was assessed using phospholipid fatty acid (PLFA) proflling. This study conflrms that any form of dehydration, when preparing soil for simultaneous biological and physical analysis, will alter the soil physical properties, and cause some change in apparent community structure. Freeze-drying (both the LNFD and −80FD treatments) was found to minimise disruption (when compared to the moist control soil) to both the soil physical properties and the community structure and is a preferable technique to air-drying which markedly alters the size and character of the pore network, as well as the phenotypic proflle. The LNFD was the preferred treatment over the −80FD treatment as samples show low variability between replicates and a fast turn-around time between samples. Therefore snap freezing in liquid nitrogen, followed by freeze drying is the most appropriate form of dehydration when two sets of data, both physical and biological, need to be preserved simultaneously from a soil core.

Volumetric water content (θv) was estimated from time domain reflectometry (TDR) measurementsof apparent dielectric permittivity (Ka) in an organic soil (Humisol). The goals of this study were: (i) to test the accuracy of existing θv-Ka relationships in this soil and if found insufficient (ii) to develop alternative θv-Ka relationships for this organic soil. The Ka values were measured over a wide range of θv in intact soil cores taken from three horizons (Ohp, Of, Oco). Empirical θv-Ka relationships found in the literature for organic porous media could not accurately describe the θv-Ka relationships of any horizon of this Humisol, probably because of the its very large organic matter content (> 75%) of this soil. New θv-Ka relationships for each horizon were consequently developed. Key words: Organic soil, TDR, coprogenic soil, volumetric water content, apparent dielectric permittivity

This study determined rates of in situ fine root decomposition and changes in trace metals concentration during decomposition at sites in Sudbury, ON, and Rouyn-Noranda, QU, with elevated or background concentrations of Cu, Ni, Pb, and/or Zn in the soil, and correlated the depth gradients of Cu, Ni, Pb, and Zn for soils and roots at the same sites. Fine roots were extracted from soil cores within root traps several times over 12 months; biomass and metal concentrations were measured. Live roots were collected from 30-cm soil cores, separated into three depths. Elevated soil metal concentrations did not necessarily reduce fine root decomposition, and effects on decomposition were similar to those previously reported for surface foliar litter at the same sites. Decomposing roots at only the high metal sites demonstrated increased metal concentrations with time. Root tissue concentrations of Cu, Ni, and Zn, but not Pb, at lower soil depths were generally higher than expected from soil metal concentr...

Forest soils are sensitive to compaction by forest machinery. Forest operations such as harvesting and skidding have a high potential for soil compaction. This study was carried out in the Hyrcanian hardwood forests of Iran to measure the changes in bulk density (ρb) in the top 10 cm of soil following machine and animal skidding. The density change or compaction was induced by (i) a rubber-tired skidder in three skid trails: flat skid trail (STF), skid trail with transversal slope (STTS), and skid trail with longitudinal gradient (STLG) and (ii) a mule in two animal trails: flat animal trail (ATF) and animal trail with transversal slope (ATTS). Soil cores were collected pre- and post-skidding at random locations along the upslope and downslope tracks of each skid trail to determine bulk density and moisture content of the soil. Average soil bulk density in the tracks of machine skid trails was significantly greater than the soil density outside the tracks, but the increase in bulk density was not significant on the animal trails. An increase in soil density was considered significant if p < 0.05. A highly significant increase in soil bulk density (p < 0.01) occurred with machine skidding after the first 12 skidding cycles on the STF before stabilizing. In comparison, on STLG and STTS the increase of bulk density was greatest after the first six skidding cycles. Additional cycles did not cause a significant increase in soil density. While the number of skidding cycles to reach the steady compaction state varied between flat trails and those with a slope, the severity of compaction was the same between them. Concentrating machine operations will minimize the areal extent of compaction and the use of mules could further reduce the impact of the extraction of short logs.

We investigated the erodibility of surface casts produced by an anecic earthworm of the Colombian savannahs by means of indoor rain simulations. The kinetic energy applied to samples, 21.62 J minute (-1) m (-2), was estimated to be equivalent to 41% of the energy of the more intense period of a local storm. The erodibility of casts was assessed at different stages of their ageing along with the effects of repeated wetting-drying cycles. Bare soil cores and soil cores of the same size with a cast on their surface (soil + cast) were used as controls. Saturated hydraulic conductivity (HC) was measured to test whether casts enhance soil water permeability. Fresh, almost liquid, individual casts were completely dispersed by a 2-hour rainfall simulation at a dispersion rate of 0.9 +/- 0.5% of sample minute (-1). After 5 hours drying at 32 degrees C and 79% relative humidity, casts were as moist as fresh casts (non-significant Mann-Whitney U-test) but had a solid appearance and were no longer dispersed by raindrop impact. Under simulated rainfall, dry casts were very slowly fragmented into large aggregates (> 5 mm). The HC of casts was increased by repeated cycles of wetting and drying but unaffected by length of air-drying and natural ageing, and averaged 7 (3, n=6), 20 (3, n= 7) and 32 (1, n = 45) cm hour (-1) for bare soil, soil + cast and all casts, respectively (standard error, sample size). Except for bare soil, these values were greater than the greatest rainfall intensities recorded locally. The consequences for soil erosion, nutrient losses and water infiltration are discussed.

Three-dimensional ground-penetrating radar (3D GPR) was used to investigate the subsurface structure of ice-wedge polygons and other features of the frozen active layer and near-surface permafrost near Barrow, Alaska. Surveys were conducted at three sites located on landscapes of different geomorphic age. At each site, sediment cores were collected and characterised to aid interpretation of GPR data. At two sites, 3D GPR was able to delineate subsurface ice-wedge networks with high fidelity. Three-dimensional GPR data also revealed a fundamental difference in ice-wedge morphology between these two sites that is consistent with differences in landscape age. At a third site, the combination of two-dimensional and 3D GPR revealed the location of an active frost boil with ataxitic cryostructure. When supplemented by analysis of soil cores, 3D GPR offers considerable potential for imaging, interpreting and 3D mapping of near-surface soil and ice structures in permafrost environments. Copyright © 2007 John Wiley & Sons, Ltd.

Disk infiltrometers are widely used to determine saturated and near-saturated soil hydraulic conductivity. Previous studies have recommended applying a high-permeability material to the undisturbed soil surface to establish a complete hydraulic bond between the disk and the infiltration surface. Other studies have shown that the use of the contact material affects the infiltration, and hence also the determination of saturated and near-saturated conductivity. In this study, we tested a new type of infiltrometer (that we call a hood infiltrometer), which might overcome these problems. Instead of requiring a disk and contact material, it places a water-filled hood, open side down, onto the soil surface. In this study, repeated hood and disk infiltrometer field tests in conjunction with time-domain reflectometry (TDR) measurements were performed at the same location to compare the performance of the two types of infiltrometer. Furthermore, we extracted undisturbed soil cores to measure the hydraulic functions in the lab. The measured hood and disk data were analyzed using Wooding's solution and by numerical parameter optimization technique using uni- and bimodal hydraulic functions. Running the disk infiltrometer with a contact layer provided saturated hydraulic conductivities that were 10 times smaller than corresponding values measured by the hood infiltrometer. We attributed these differences to smearing, sealing, and clogging of pores, which led to additional flow impedances in the soil surface layer. We were able to show, however, that the combined use of hood and disk infiltrometers in conjunction with TDR enabled hydraulic characterization of the soil from saturation to dry conditions.

The direct-push (DP) approach for characterization of the shallow unconsolidated sub-surface is a rapidly developing methodology that deploys hydrogeological, geotechnical, and geophysical tools in the sub-surface. It offers significant advantages as compared to techniques using traditional drilling and permanent piezometers, but requires real-time on-site decisions. Selection of the number of tests, sequence, location, and depth makes the planning stage crucial for successful and effective field studies. Whereas the analysis of various DP-based hydrogeological, geotechnical, and geophysical methods is well presented in the literature, recommendations for planning DP field applications are scarce. We illustrate applications of DP-based techniques (electrical conductivity profiling of the aquifer, groundwater sampling, slug testing, and soil core extraction) for evaluation of aquifer-lake interactions in a remote and poorly accessible area of the Nebraska Sand Hills with numerous saline lakes. In addition to the background data on hydrostratigraphy and groundwater salinity, we report an approach to combining and optimizing the DP techniques, including the work sequence, depth limitations, data quantity, and scheduling. The data and insights gained will be useful in designing characterization programs in other sand dune-lake environments.

The turnover of fine roots in northern coniferous forests has conventionally been assumed to be rapid, in line with results from sequential coring in the late 1970s in a Swedish Scots pine stand (SWECON project) where a rate of 7.4 year−1 was estimated. New quantifications of the root respiration in other stands motivated a recalculation of the SWECON data; an indirect estimation of the turnover rate was much slower, about 2.1 year−1. As a consequence, fine-root production is considered to be much lower than in previous estimates. Furthermore, direct observations of Norway spruce fine roots (

We hypothesized the seed biomass available to migrating waterfowl would be higher in spring- versus fall-flooded wetlands. To test this hypothesis we conducted an experiment using 5 pairs of wetland impoundments in northern Missouri, USA (2000–2002). We strategically assigned one impoundment of each pair to either a fall or spring treatment group. We estimated seed biomass in fall and in spring by clipping seed heads and collecting soil cores at 20 random locations within each impoundment. We placed exclosures near each fall sample site in spring-flooded impoundments to estimate seed loss from granivorous birds and rodents. Despite similar biomass in fall between treatments (P = 0.64), overwinter seed loss was greater in fall-flooded (79%; 1,324 ± 195 kg/ha) than in spring-flooded (31%; 653 ± 130 kg/ha) impoundments (P = 0.009). Considering barnyard grass or millet (Echinochloa spp.) only, seed loss was higher in fall-flooded than in spring-flooded impoundments (P = 0.05). Spring biomass estimate...

Soybean [Glycine max (L.) Merr.] yield in claypan soils varies systematically with soil properties and landscape position. This is likely caused by soil interactions with soybean roots. Field observations of soybean root distribution are needed to reveal its effect on yield variability. This study examined profi le distributions of soybean root length density (RLD) and average root diameter (ARD) as a function of landscape position, depth to claypan (DTC), apparent soil electrical conductivity (EC a ), clay-maximum translated depth (D t ), and other soil properties. A landscape of claypan soils was sampled postharvest at two sites near Centralia, MO, in 2001. Roots were washed from soil cores in 15-cm layers (15–120 cm) and measured with image analysis. Root length density and ARD were signifi cantly related to landscape position, DTC, D t , and EC a . Predictions of RLD and ARD were best from 15 to 60 cm, the depths with the greatest infl uence from claypan soil morphology. Soil profi le distributions of base cations, P, and pH matched root density profi les. Soybean roots were inhibited in E horizons above the claypan and stimulated 20 to 40 cm below it. Soybean roots below the claypan had about 20 to 30% smaller diameter. We conclude that DTC and rapid estimators of claypan morphology, such as EC a , can be used to predict soybean root distribution in claypan soil landscapes.

Soil samples were collected from six different locations in Araba valley, situated between Aqaba port and Dead sea. The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean activity concentration for (238)U, (232)Th and (40)K was found to be in the range 19 +/- 1.4 to 38.7 +/- 3, 14.3 +/- 0.8 to 35 +/- 3.2 and 94 +/- 18.9 to 762 +/- 47.4 Bq kg(-1), respectively. These results indicate that the mean concentrations of (238)U, (232)Th and (40)K in the populated Araba valley are lower than those in other populated areas. On the other hand, the concentrations of the major oxides (Al(2)O(3), SiO(2), K(2)O, CaO and Fe(2)O(3)) in the samples were determined using wavelength dispersive X-ray fluorescence. High potassium and iron content in some samples might be attributed to the active faults, which refer to the Dead sea transform fault.

Fipronil termiticide belongs to phenyl-pyrazole class of chemical compounds. It has broad-spectrum activity particularly against house hold pests such as cockroaches, mosquitoes, locusts, ticks, and fleas at both larval and adult stages. At high dosage it can be used to control subterranean termites in building foundations. To evaluate long term efficacy against termites the persistence and vertical distribution of fipronil was studied under natural weather conditions of Dehradun, India. Fipronil was applied at four concentrations i.e. 0.05, 0.1, 0.25 and 0.5% a.i ha(-1) by drenching 17 x 17 in.(2) plot prepared as per modified ground board test. Soil samples were collected after 22, 38 and 56 months of treatment up to the depth of 75 cm. The soil core was cut into five distinct sections i.e. 0-15, 15-30, 30-45, 45-60 and 60-75 cm depth. The residues were extracted by shaking 20 g soil sample with acetone. The acetone extract was concentrated and cleaned-up over florisil column. Fipronil residues were estimated on GLC at 220, 260, and 300 degrees C oven, injector and detector temperature respectively. Fipronil was found to persist beyond 56 months after application. Two metabolites viz. desulfinyl and sulfide-fipronil were detected in sampling after 22 months of application that also dissipated with time. Fipronil residues were found up to 60 cm depth. The residues in deeper layers dissipate slowly with time and after 56 months of treatment residues were detected only up to 30 cm depth.

We investigated seasonal root production and root turnover of fertilized and wellwatered monocultures of Phalaris for 2 years using minirhizotrons installed in six newly designed temperature gradient tunnels, combined with sequential soil coring. Elevated atmospheric CO2 treatments were combined with two cutting frequencies and three warming scenarios: no warming, 13.0/13.0 and 12.2/14.01C (day/night) atmospheric warming. The elevated CO2 treatment increased both new and net root length production primarily when combined with atmospheric warming, where the constant warming treatment had a greater positive effect than the increased night-time warming treatment. Responses to elevated CO2 were greater when the swards were cut more frequently and responsiveness varied with season. For Phalaris swards, 17% of total net primary productivity went belowground. On account of root turnover, only one-third of the new roots produced in the year following establishment could be expected, on average, to be recovered from soil cores. The interaction between the effects of CO2 and warming, combined with the differential effects of the two warming treatments, has important implications for modelling belowground responses to projected climate change.

The Maoershan forestry centre is situated in the Zhangguangcai Mountain of the Changbai mountain range. The main forest types in the Maoershan region are plantation (Pinus sylvestris var. mongolica, Pinus koraiensis and Larix gmelinii) and natural secondary forests (Fraxinus mandshurica, Quercus mongolica and Populus davidiana). Fine roots have enormous surface areas, growing and turning over quickly, which plays an important role in terms of substance cycling and energy flow in the forest ecosystem. This study deals with the dynamics of live, dead, and total fine roots (≤ 5 mm) biomass in the 0–30 cm soil layer using the soil core method. Differences between the six stands in the Maoershan region showed the following results: 1) the fine root biomass in the various stands showed obvious differences. The total fine root biomass of six stands from high to low were F. mandshurica (1,030.0 g/m2) > Q. mongolica (973.4 g/m2) > Pinus koraiensis (780.9 g/m2) > L. gmelinii (718.2 g/m2) > Populus davidiana (709.1 g/m2) > Pinus sylvestris var. mongolica (470.4 g/m2); 2) except for L. gmelinii, the development of live fine root biomass agreed with the trend of total fine root biomass. The maximum biomass of live fine roots in Pinus koraiensis or L. gmelinii stand appeared in May, others in June; in the F. mandshurica stand, the minimum biomass of live fine roots occurred in September, others in July or August; 3) the proportions of dead fine root biomass varied in different stands; 4) the vertical distribution of fine roots was affected by temperature, water, and nutrients; the proportion of fine root biomass was concentrated in the 0–10 cm soil layer. The fine root biomass of six stands in the 0–10 cm soil layer was over 40% of the total fine root biomass; this proportion was 60.3% in F. mandshurica. Space-time dynamics of the various stands had different characteristics. When investigating the substance cycling and energy flows of all forest ecosystems, we should consider the characteristics of different stands in order to improve the precision of our estimates.

Soil organic carbon (SOC) sequestration is an important process to mitigate CO 2 emissions. Our objectives were to determine the rates of C sequestration and to determine if the SOC pool was at or approaching equilibrium in plots under long-term (24-yr) conservation (CT) and disk tillage (DT) management. The plots were Norfolk loamy sand (fine-loamy, kaolinitic, thermic, Typic Kandiudult) and were under a row crop rotation. All plots received annual subsoiling, while only plots under DT were surface disked. Soil cores were collected to 90 cm deep. After 24 yr, the only significant increase in SOC occurred in CT plots at a 0- to 5-cm depth. The SOC pool in plots under DT was at a near-steady state, while the SOC pool under CT was not at equilibrium. This supports the conclusion that CT is an effective countermeasure to offset atmospheric CO 2 emissions.

Inventories of radionuclides commonly used to study environmental processes, especially in erosion research, were determined in soil cores from two distant river basins in northern Spain. Results showed that 210 Pb atmospheric fluxes correlate very well with mean annual rainfall across the region, and this is also the case for 137 Cs inventories but only on the basin scale. Therefore we suggest that 210 Pb is a better candidate as a radiotracer for soil erosion studies. In this region, the equation 210 Pb flux (Bq m -2 yr -1 ) = (0.19 ± 0.02) x rainfall (mm yr -1 )- (24 ± 17) can be used as a calibration to estimate input 210 Pb fluxes, a key parameter in soil erosion studies and models, when mean annual rainfall is known.

Determination of the Initial 137Cs Fallout on the Areas Contaminated by Chernobyl Fallout The fallout radioisotope 137Cs is widely used to study rates and patterns of soil redistribution. This method requires the knowledge about the initial fallout of cesium in the study area. This paper describes the method of establishing the initial fallout of cesium for a study area which is contaminated by Chernobyl fallout. The study was carried out on the loess area near the Ujazd village (South-West Poland). The 137Cs activities for reference soil cores varied from 4.41(24) kBq/m2 to 5.97(26) kBq/m2. The average value of the reference inventory of 137Cs for the study area is 5.23(15) kBq/m2. The calculated contribution of the Chernobyl 137Cs fallout in the total cesium is equal 69%. Moreover the annual values of the 137Cs fallout based on the precipitation data were calculated and presented. This study provides the method of calculating the 137Cs fallout connected with the nuclear weapon testing based on the precipitation data. Moreover, this study also indicated that the spatial variability on the highly contaminated by Chernobyl cesium study area is small (RSD about 10%) and thus it is possible to use the cesium method to study soil redistribution.