Effect Of Soil Parameters Research Articles

Chemometric approach for prediction of uranium pathways in the soil

Abstract Understanding the effect of soil parameters (pH, Eh and organic and inorganic ligands availability) on uranium mobility under different geochemical conditions is fundamental for reliable prediction of its behaviour and fate in the environment. In this study, the impact of total and available phosphorus content, humus and acidity of Serbian agricultural soils on the content of total and available uranium were evaluated by Response Surface Methodology (RSM), second order polynomial regression models (SOPs) and artificial neural networks (ANNs). The performance of ANNs was compared with the performance of SOPs and experimental results. SOPs showed high coefficients of determination (0.785–0.956), while ANN model performed high prediction accuracy: 0.8893–0.904. According to the results, total and available uranium content in the soil were mostly affected by pH, statistically significant at p < 0.05 level. For the same responses the total phosphorus was found to be also very influential, statistically significant at p < 0.05 and p < 0.10 levels. The impact of available phosphourus and humus was much more influential on total and available uranium content, compared to total phosphorus content. Proposed chemometric approach will be very helpful in preserving the natural resources and practical application for risk assessment modeling of uranium environmental pathways.

Effect of Soil Parameters on the Kinetics of the Displacement of Fe from FeEDDHA Chelates by Cu

In soil application, o,o-FeEDDHA (iron (3+) ethylene diamine-N,N'-bis(2-hydroxy phenyl acetic acid) complex) is the active ingredient of FeEDDHA chelate-based Fe fertilizers. The effectiveness of o,o-FeEDDHA is potentially compromised by the displacement of Fe from FeEDDHA by Cu. The actual impact of Cu competition is codetermined by the kinetics of the displacement reaction. In this study, the influence of soil parameters on the displacement kinetics has been examined in goethite suspensions. The displacement reaction predominantly takes place on the reactive surface rather than in solution. The rate at which the o,o-FeEDDHA concentration declined depended on the available reactive surface area, the Cu loading, and the FeEDDHA loading. Soil factors reducing FeEDDHA adsorption (high ionic strength, humic acid adsorption onto the goethite surface, and monovalent instead of divalent cations in the electrolyte) decreased the displacement rate. For meso o,o-FeEDDHA, the displacement rate equation was derived, which is first order in FeEDDHA loading and half order in Cu loading. For soil conditions, the equation can be simplified to an exponential decay function in meso o,o-FeEDDHA solution concentration.

Estimating the biodiversity of understory plant species in afforestation and land sliding areas of Alder stands

After natural disturbance and human activities, the processes of regeneration and succession play an important role in increasing forest dynamics. In this study 51 sample plots were established to evaluate the status of plant species biodiversity in afforestation and landslide areas and to assess the effects of soil parameters on tree species community in Alder stands. Our measure of understory plant species biodiversity and evenness was based on computations in ecological methodology software. Species richness was calculated in PAST program. Results showed that the richness index of herbaceous species in control plots was more than that of landslide and afforestation areas. The evenness index of herbaceous in control plots was more than that of landslide and afforestation areas. Similar results were observed for biodiversity index. The richness index of regenerated tree species in landslide areas was more than that of control and afforestation plots, except for Berger-parker index. Moreover, the evenness index of regenerated tree species can be arranged as landslide plots > control plots > afforestation plots. Similar results were recorded for biodiversity index. Key words: Biodiversity, afforestation, land slide, Alder, Darab Kola.

Effect of Soil Parameters on Elastic Characteristics of Subgrade Materials

AbstractIn this paper, state-dependent elastic characteristics of granular subgrade materials were investigated, assuming various field conditions. For this purpose, a series of resonant column tests were conducted. The test materials were cohesionless soils consisting of clean and silty sands with different fines contents. The effects of moisture content, overconsolidation ratio, relative density, and confining stress on the elastic modulus were analyzed. From the test results, it was observed that the initial shear modulus, G0, decreases with increasing moisture content because of reduced particle contact friction. Higher fines content produced a more pronounced modulus reduction at the same moisture content. It was also found that the effect of fines content on G0 becomes smaller as the relative density and confining stress increase. These results indicate that the moisture effect on G0 is important at shallow depths such as subgrade layers. A modulus reduction factor was proposed, which can reflect th...

Characteristics of Negative Skin Friction for Superlong Piles under Surcharge Loading

This paper presents the study of negative skin friction of the superlong pile caused by the soil settlement under large-scale surcharge loading. Based on the displacement equilibrium principle and transfer matrix method, with the introduction of a load transfer model considering shaft resistance softening, the analytical model of negative skin friction of superlong pile under surcharge loading is established by considering the three-dimensional consolidation settlement along the pile under surcharge loading, the compression deformation of pile, and the soil settlement around pile-end. Three-dimensional Biot consolidation is used to derive the settlement of soil surrounding pile and the settlement formula is simplified by using the Laplace and Hankel integral transform. Furthermore, the analysis is conducted for an engineering example using the theoretical model and FEM simulation method. The results are also compared with the corresponding measured data. The characteristics of negative skin friction of superlong pile under surcharge loading are obtained, and the effect of soil parameters on negative skin friction is discussed as well, which can offer valuable reference for the design of superlong piles.

A high efficacy steam soil disinfestation system, part II: Design and testing

The adoption of ecological solutions to eradicate soil-borne pathogens and weed seeds in horticulture is needed to protect both the environment and consumer safety. For these reasons, soil steaming, which was practiced in the past but has since been substituted by cheaper chemical treatments, is now being considered again. The lack of mechanisation of this technique and the high fuel consumption persuaded farmers to reject this disinfestation method. This paper presents the design, development and testing of a non-conventional steam application system for soil disinfestation, based on the coupling of an iron hood and a set of injectors. The device has been assembled on a caterpillar machine, equipped with a steam generator and an automatic guidance system, and tested in the open field. The equipment design followed extensive laboratory experimentation, reported in the companion paper ( Gay, Piccarolo, Ricauda Aimonino, & Tortia, 2010 ), during which the effect of soil parameters on heat efficiency was assessed for different steam supply devices.

Estimation of nitrous oxide emission from Hungarian semi-arid sandy and loess grasslands; effect of soil parameters, grazing, irrigation and use of fertilizer

Nitrous oxide (N 2O) is emitted into the atmosphere in substantial quantities as an intermediate product of mainly denitrification processes and soil nitrification. N 2O emission from Hungarian sandy and loess type soils has been measured between August 2002 and December 2004. The effects of soil parameters and different farming activities (grazing exclusion, irrigation and mineral fertilization) on the rate of emission were investigated. Soil N 2O efflux was determined by measuring the accumulation of N 2O in 10 parallel small ( V = 400 cm 3, A = 80 cm 2) static chambers. Samples were taken with evacuated tubes followed by gas chromatography–mass spectrometry analysis. Emission from sandy grassland under extensive farming proved to be negligible below soil temperature of 5 °C, the mean fluxes at t soil > 10 °C and t soil < 10 °C were differing significantly (15.4 and 1.7 μg N m −2 h −1, respectively). N 2O efflux was linked to temperatures up to t soil = 20 °C, while at higher soil temperatures a decrease of efflux was observed. The optimum soil wetness (WFPS, water-filled pore space) for N 2O production was between 40 and 50% for this sandy soil. The annual sum of efflux for control plots in dry (2003) and wet (2004) years was almost the same (0.80 and 0.74 kg N ha −1 yr −1, respectively), probably due to the fact that in dry year soil wetness is lower than the optimum, and vice versa, in a wet year the high WFPS did not favoured N 2O production. Grazing (50–80 cows per km 2) enhanced emission by 4–18% in dry and wet years, respectively. Around 6% of total atmospheric deposition (13.8 kg N ha −1 yr −1) was transformed into N 2O and emitted into the atmosphere from the sandy soil. A two-year fertilization experiment above loess soil (August 2002–July 2004, with regular precipitation amount during the period) resulted in an emission factor of 0.26% as a consequence of applying 100 kg N ha −1 yr −1 ammonium nitrate mineral fertilizer in April, each year. Average fluxes were 1.13 and 0.90 kg N ha −1 yr −1 above fertilized and control plots, respectively. Monoliths from loess soil were used to study the effect of irrigation on N 2O fluxes. In contrast to sandy soil there were detectable soil fluxes below 5 °C. N 2O production increases with soil temperature until 15–20 °C above which lower emissions were detected. The optimum wetness for N 2O production in loess soil was around 30–40 WFPS but above 70–80% (up to saturation) other, yet unexplained maximum was observed. Irrigation enhanced the soil flux by 70% in the dry year (2003), when measured fluxes were 1.56 and 0.92 kg N ha −1 yr −1 on irrigated and control plots, respectively.

A high efficiency steam soil disinfestation system, part I: Physical background and steam supply optimisation

Steam soil disinfestation is now being reconsidered in open field and greenhouse horticulture for its efficiency in controlling or even eradicating soil borne pathogens, nematodes and weed seeds, while ensuring low ecological impact. Due to the high energy and labour costs of this treatment, technical solutions able to increase efficiency and to reduce workload are needed and are being sought. This paper presents the design, development and testing of two steam supply systems for soil disinfestation. Since soil conditions, in terms of texture and humidity, play an important role and significantly influence the efficacy of the treatment, determining the thermal properties of the soil and influencing steam diffusion, the equipment design followed an extensive laboratory experimentation phase during which the effect of soil parameters on heat efficiency was assessed. In a companion paper ( Gay et al., in press ), an innovative implement, based on the coupling of the two devices presented in this paper, has been built, connected to a caterpillar track machine, equipped with a steam generator and an automatic guidance system, and used in open field tests.

Cultivation Practices and Potato Cultivars Suitable for Organic Potato Production

To identify the most important agronomic measures and cultivar traits in Swedish organic potato production, multivariate analyses were performed on a set of data from a series of field trials carried out in Sweden during a 7-year period. The effects of soil parameters, cultivar, year and geographical location on potato characteristics were investigated. Soil parameters including fertility level had strong and significant effects on potato characteristics, explaining 53% of total variation. Variables related to the duration of haulm growth were other dominant factors in the variation. While P and K fertilization increased yields, N fertilization had little effect on yield and a negative effect on the time to emergence. The N requirement of potatoes ranges from 2.5 to 5.9 kg ha−1 per ton of tuber yield and was met in these trials. The results implied the timing of N application is important for yield. It was concluded that the importance of P and K fertilization is underestimated in organic production, and that the most important cultivar trait in achieving acceptable yield is long-lasting foliage, which is a characteristic of cultivars resistant to Phytophthora infestans. Three of the cultivars tested (Lady Balfour, Cicero and Sarpo Mira) had a yield >3.5 kg m−2, which is high in Swedish organic production.

Parameter Sensitivity in LSMs: An Analysis Using Stochastic Soil Moisture Models and ELDAS Soil Parameters

Abstract Integration of simulated and observed states through data assimilation as well as model evaluation requires a realistic representation of soil moisture in land surface models (LSMs). However, soil moisture in LSMs is sensitive to a range of uncertain input parameters, and intermodel differences in parameter values are often large. Here, the effect of soil parameters on soil moisture and evapotranspiration are investigated by using parameters from three different LSMs participating in the European Land Data Assimilation System (ELDAS) project. To prevent compensating effects from other than soil parameters, the effects are evaluated within a common framework of parsimonious stochastic soil moisture models. First, soil parameters are shown to affect soil moisture more strongly than the average evapotranspiration. In arid climates, the effect of soil parameters is on the variance rather than the mean, and the intermodel flux differences are smallest. Soil parameters from the ELDAS LSMs differ strongly, most notably in the available moisture content between the wilting point and the critical moisture content, which differ by a factor of 3. The ELDAS parameters can lead to differences in mean volumetric soil moisture as high as 0.10 and an average evapotranspiration of 10%–20% for the investigated parameter range. The parsimonious framework presented here can be used to investigate first-order parameter sensitivities under a range of climate conditions without using full LSM simulations. The results are consistent with many other studies using different LSMs under a more limited range of possible forcing conditions.

Effect of Soil Parameters on Dynamic Cone Penetration Indices of Laterite Sub-grade Soils from India

The focus of this study was on correlating the effect of grain-size, maximum dry-density (MDD), field moisture content, and the void ratios on penetration measured using the dynamic cone penetrometer (DCP) for laterite soils blended with fines. Tests were performed on soil samples compacted to MDD for moulding water contents set to the optimum moisture content (OMC), dry of OMC, and wet of OMC un-soaked condition. The results indicated that an increase in the fines-content caused a decrease in the MDD, and an increase in the OMC and the DCP penetration. Regressions were developed correlating various parameters.

Can we predict uranium bioavailability based on soil parameters? Part 1: Effect of soil parameters on soil solution uranium concentration

Present study aims to quantify the influence of soil parameters on soil solution uranium concentration for 238U spiked soils. Eighteen soils collected under pasture were selected such that they covered a wide range for those parameters hypothesised as being potentially important in determining U sorption. Maximum soil solution uranium concentrations were observed at alkaline pH, high inorganic carbon content and low cation exchange capacity, organic matter content, clay content, amorphous Fe and phosphate levels. Except for the significant correlation between the solid-liquid distribution coefficients ( K d, L kg −1) and the organic matter content ( R 2 = 0.70) and amorphous Fe content ( R 2 = 0.63), there was no single soil parameter significantly explaining the soil solution uranium concentration (which varied 100-fold). Above pH = 6, log( K d) was linearly related with pH [log( K d) = − 1.18 pH + 10.8, R 2 = 0.65]. Multiple linear regression analysis did result in improved predictions of the soil solution uranium concentration but the model was complex.

Effect of soil parameters on radon entry into a building by means of the transrad numerical model.

High indoor radon concentration means an increased risk of developing lung cancer. When high radon levels are present in a dwelling, the major source is normally the soil. Therefore, it is useful to know the radon concentration field in the soil underneath a building. A steady-state two-dimensional radon transport model has been used to calculate the effect of a reference building on the soil radon concentration, and the influence of soil parameters on radon entry through a single crack in the basement. Both advective and diffusive flows are considered. Away from the building, the well-known undisturbed soil radon concentration profile has been obtained, while under the house the radon level is increased. A variability analysis around the reference site has shown that the most relevant soil parameters on the radon flux at the top of the crack are, in this case, effective diffusion coefficient, soil gas-permeability and deep soil radon concentration.

Effect of soil parameters on the friction coefficient in reinforced earth : Indian Geotech JV18, N4, Oct 1988, P322–339

Effect of soil parameters on the friction coefficient in reinforced earth : Indian Geotech JV18, N4, Oct 1988, P322–339

Effects of soil parameters on pore-pressure-rise and liquefaction prediction : Soils found, V22, N1, March 1982, P39–48

Effects of soil parameters on pore-pressure-rise and liquefaction prediction : Soils found, V22, N1, March 1982, P39–48

Neutron Moisture Meters: The Effects of Various Soil Parameters

Multigroup nuclear reactor codes were used to determine the effect of soil parameters on the thermal neutron flux at the detector of a neutron moisture meter. The parameters studied were the matrix...