Quantification Of Organic Carbon Research Articles

Total organic carbon quantification in soils and sediments: Performance test of a modified sample preparation method

The total organic carbon (TOC) concentration of particulate samples is a key parameter to characterize soils and sediments. To demonstrate the applicability and reliability of a modified sample preparation method for the direct measurement of TOC contents in suspended particulate samples, we analyzed five certified reference materials (CRMs) with varying TOC concentrations using a Shimadzu TOC-L CPH analyzer. Measured values were calibrated with a multi-point curve that cover the full range of the expected TOC concentrations and the results were validated using statistical values and measures. The method validation reveals that the measurements are accurate and precise for CRMs from marine and soil contexts, but show a low accuracy for the CRM containing polycyclic aromatic hydrocarbons (PAHs). This demonstrates the applicability and reliability of the modified preparation method for direct TOC determination of suspended particulate samples. Therefore, it is relevant for a broader community, beyond geosciences, and for users employing devices of other manufacturers to analyze TOC in suspended particulate samples.•Modified preparation method uses reduced sample weights and yields accurate and precise results.•Cost-efficient and environmentally friendly alternative: reduces waste by saving acid and ultrapure water.•Avoids incomplete dissolution of dolomite by heating acidified samples.

On the impact of soil texture on local scale organic carbon quantification: From airborne to spaceborne sensing domains

Soil organic carbon (SOC) distribution and interaction with light is influenced by soil texture parameters (clay, silt and sand), which makes SOC prediction complicated, especially in samples with considerable pedological variability. Hence, understanding the relationship between SOC and soil texture is important within the context of SOC prediction using remote sensing data. The main objective of this study was to find the impact of soil texture on the performance of local SOC prediction models that were developed on Sentinel-2 (S2) multispectral and CASI/SASI (CS) hyperspectral airborne data as the main predictor variables. One approach to that objective was to lowering the texture variance by stratification of the samples. Therefore, soil samples collected from four agricultural sites in the Czech Republic were segregated based on the i) site-based and ii) texture-based stratification strategies. Random forest (RF) models were then developed on all stratified classes with and without considering the soil texture parameters as predictor variables and results were compared with those obtained by the RF models developed on the non-stratified (NS) samples. Both stratification strategies provided more homogeneous classes, which enhanced the accuracy of SOC prediction, compared to using the NS samples. In addition, the texture-based RF models yielded higher accuracy predictions than the site-based ones. Except sand, adding texture parameters to the main predictors improved accuracy of the models, so that the highest prediction performance was obtained by a texture-based model developed on clay added CS data. Overall, texture-based stratification could significantly enhance the SOC prediction, when the texture parameters were added to the S2 and CS data as the main predictor variables.

Quantifying organic carbon in particulate and mineral-associated fractions of calcareous soils – A method comparison

Accurate quantification of soil organic carbon (OC) pools is essential to study the dynamics of OC in soils. Therefore, organic matter is often separated into physical fractions with distinct turnover times, e.g. particulate (POM) and mineral-associated organic matter (MAOM), after which their OC content is measured. Calcareous soils are under-represented in such fractionation studies, because the required analytical differentiation between OC and inorganic carbon (IC) is not straightforward and implies more processing time, sample mass and equipment. Here, we review the performance of four methods to quantify OC in POM and MAOM fractions of soils containing 3–16 g IC kg−1 and 10–25 g OC kg−1 (n = 16). We assessed the similarity and consistency of the data obtained with the different methods. Furthermore, we checked how their ability to distinguish OC from IC was influenced by the fractionation and in particular by the dispersion with sodium hexametaphosphate (SHMP). The four methods were: 1) Elemental carbon analysis after removal of IC by acid fumigation (OCfum); 2) Elemental carbon analysis after removal of IC with aqueous acid (OCaq); 3) Elemental carbon as determined by Rock-Eval 6 thermal analysis (OCRE6); and 4) Elemental carbon analysis after removal of OC by loss on ignition and subsequent quantification of OC by difference between total carbon and IC (OCLOI). We found that the OCfum, OCaq, and OCLOI methods produced similar OC contents for bulk soils, whereas OCRE6 results were slightly but significantly lower. Total recovered OCRE6 contents of the summed POM and MAOM fractions were similar to the bulk soil OCRE6 contents. In contrast, the recovered OCfum, OCaq and OCLOI contents were slightly higher than respective bulk soil OC contents (108–112%), especially in soils with high IC/OC ratios. We show that this was not caused by operational artefacts or chemical changes that occurred during OC fractionation, but rather likely indicated error propagation. We conclude that all 4 methods can reliably quantify OC in POM and MAOM fractions in calcareous soils and that the optimal choice depends on the required accuracy of the results and the available sample mass, lab equipment and processing time. Based on our findings and practical considerations, we provide guidance for the selection of the most optimal OC quantification method to study OC dynamics in calcareous soils.

Artificial neural network implementation for dissolved organic carbon quantification using fluorescence intensity as a predictor in wastewater treatment plants

Although spectroscopic methods provide a fast and cost-effective means of monitoring dissolved organic carbon (DOC) in natural and engineered water systems, the prediction accuracy of these methods is limited by the complex relationship between optical properties and DOC concentration. In this study, we developed DOC prediction models using multiple linear/log-linear regression and feedforward artificial neural network (ANN) and investigated the effectiveness of spectroscopic properties, such as fluorescence intensity and UV absorption at 254 nm (UV254), as predictors. Optimum predictors were identified based on correlation analysis to construct models using single and multiple predictors. We compared the peak-picking and parallel factor analysis (PARAFAC) methods for selecting appropriate fluorescence wavelengths. Both methods had similar prediction capability (p-values >0.05), suggesting PARAFAC was not necessary for choosing fluorescence predictors. Fluorescence peak T was identified as a more accurate predictor than UV254. Combining UV254 and multiple fluorescence peak intensities as predictors further improved the prediction capability of the models. The ANN models outperformed the linear/log-linear regression models with multiple predictors, achieving higher prediction accuracy (peak-picking: R2 = 0.8978, RMSE = 0.3105 mg/L; PARAFAC: R2 = 0.9079, RMSE = 0.2989 mg/L). These findings suggest the potential to develop a real-time DOC concentration sensor based on optical properties using an ANN for signal processing.

Quantification of Organic Carbon in Soils of the Derived Savannah Using Four Different Methods

Quantification of Organic Carbon in Soils of the Derived Savannah Using Four Different Methods

Quantification of organic carbon and black carbon emissions, distribution, and carbon variation in diverse vegetative ecosystems across India

Black Carbon (BC) and Organic Carbon (OC) are the principal chemical aerosol components generated during combustion, both of which play a key role in air pollution, human health and climate change. Several studies of OC and BC have been conducted over India to assess the contribution from household and fossil fuel-based sources; however, studies on their emissions and their contribution from forest and cropland fires are quite limited. To address this issue, as part of this research, we derived a vegetation burning-based inventory of BC and OC aerosols over India at a resolution of 250 m × 250 m. Using a consumed biomass technique, we estimated emissions based on updated emission factor estimates. During the fire season in India (March–June), the mean OC and BC emissions were 2.1 ± 5.2 × 1013 kg per year and 1.8 ± 4.4 × 1012 kg per year, respectively. Andhra Pradesh had the highest total carbonaceous aerosol emissions during the study period. Forest fires were prevalent in the northeastern states, while agricultural fires were prevalent in Gujarat, Chhattisgarh, Odisha, Madhya Pradesh, Bihar, Tripura, Uttar Pradesh, and Andhra Pradesh. The previous inventory, conducted at a coarser resolution (25 km × 25 km), overestimated open burning by 5 Mt. Our results were highly correlated with global bottom-up model values, especially the Fire Inventory (FINN). Our analysis showed that vegetative burning contributed 80.32% of the total carbon stock, with agricultural burning being the largest source of vegetative burning. Based on these findings, measures and strategies to control agricultural burning which would reduce significantly the total emissions of BC and OC with implications to improvement in air quality, human health and climate should be planned.

Quantification of Organic Carbon Sequestered by Biogenic Iron Sulfide Minerals in Long-Term Anoxic Laboratory Incubations.

Organic carbon sequestration in sedimentary environments controls oxygen and carbon dioxide concentrations in the atmosphere. While minerals play an important role in the preservation of organic carbon, there is a lack of understanding about the formation and stability of organo-mineral interactions in anoxic environments, especially those involving authigenic iron sulfide minerals. In this study, we quantified organic carbon and nitrogen sequestered in biogenic iron sulfide minerals co-precipitated with sulfate-reducing bacteria (SRB) in freshwater and marine conditions in long-term laboratory experiments. The amounts of C and N associated with biogenic iron sulfide minerals increased with increasing cell biomass concentrations available in the media. C and N levels stabilized over the first 2 months of incubation and remained stable for up to 1 year. Crystalline mackinawite (FeS) formed in all experimental conditions and transformed to greigite only in some experimental conditions. We did not find evidence that this mineral transformation affected C and N levels, neither could we identify the factors that controlled greigite formation. Pyrite did not form in our experimental conditions. While C concentrations in minerals correlated with concentrations of reduced sulfate in both the freshwater and marine media, removal of OC by iron sulfide minerals was more efficient in freshwater than marine conditions. Removal of OC by iron sulfide minerals was also more efficient when cells were present (SRB biomass) in comparison with abiotic incubations with organic mixtures (e.g., tryptone, yeast extract, and casamino acids). Our study highlights the potential for biogenic iron sulfide minerals to quantitatively contribute to organic carbon preservation in anoxic environments.

Favorable morphoclimatic factors for the preservation of wetting organic carbon in mountain soils

Humic substances (HS) are the main component of soil organic matter (SOM), a product of the pedogenetic process. In this study, the morphometric factors and climatic variable that condition the degree of humification, the organic carbon content of humic acids (HA) fulvic acids (FA) of 42 soil samples are related through the functional equation of factors of state of the soil proposed by Jenny. The degree of humification was determined by the Nagoya method proposed by Kumada. The quantification of organic carbon was determined using the method by Walkley and Black. The morphometric parameters of the relief were obtained from the Digital Elevation Model (DEM) and the climate parameter of the MODIS sensor. The results show that the relief factor conditions the degree of humification and the climate factor conditions the organic carbon content of humic acids (HA) and fulvic acids (FA).

Comparison of organic carbon from humic and fulvic acids and the degree of humification in five soil orders

This study compared the organic carbon (OC) content in fractions of humic acids (HA) and fulvic acids (FA) in five soil orders (Aridisol, Entisol, Histosol, Inceptisol and Mollisol) and know their association with the degree of humification. Extraction and fractionation, as well as the degree of humification was carried out by the Nagoya method proposed by Kumada. OC quantification was determined by the Walkley and Black method. The results are: the average OC content of HAs of the order Aridisol differs from that of Histosols, Inceptisols, and Mollisols. The order Entisol presented differences with the Histosols and Mollisols, the soils of the order Inceptisol presented differences with the Aridisols and Histosols and those of the order Histosol differed from the Aridisols, Entisols and Inceptisols. Similarly, those of the Mollisol order differed with the Aridisols, Entisols and Inceptisols. In the fraction of FA the average OC content of the order Aridisol deferred from that found in Histosols, Inceptisols and Mollisols. The Entisol order differed from the Mollisols; likewise, the Inceptisol order differed from the Aridisols and Mollisols and the Histosol order differed from the Aridisols. Finally, the order Mollisol was also different from the Aridisols, Entisols, and Inceptisols. Soil types do not show wetting patterns, because they are not based on pedogenetic processes and these have a wide range of characteristics in surface horizons.

Feeding habits of Holothuria (Stauropora) fuscocinerea (Echinodermata: Holothuroidea) in a Mexican Pacific reef

Introduction: The importance of holothuroids in marine ecosystems is related to their feeding activities, which have been little studied in the eastern Pacific. Objective: To describe the feeding habits of the sea cucumber Holothuria (Stauropora) fuscocinerea and their bioturbation potential in La Entrega reef, México. Methods: The population size of H. (Stauropora) fuscocinerea was determined by means of four 20 x 4 m (320 m2) band transects, while the available sediment for the sea cucumbers and their feces were characterized in three stations (A-C) via granulometry and quantification of organic carbon and organic matter. Excretion rate was determined every 4 hr over a 24 hr period and the relationship between sea cucumber length and biomass and the excretion rate evaluated. Results: According to non-parametric permutation, ordination and percentage similarity analyses, sea cucumber feces mostly comprised a large proportion of small grains compared to the available sediment, indicating that H. (Stauropora) fuscocinerea is selective on grain size. Preliminary bioturbation potential of the species may reach up to 8.71 ± 0.17 kg day of sediment in the study area. Conclusion: The spatial distribution of H. (Stauropora) fuscocinerea in the study area is a product of its selective feeding activity, evidencing the preliminary importance of the species in the trophic dynamics of La Entrega reef.

Rapid PXRF soil organic carbon and organic matter assessment using novel modular radiation detector assembly

Soil organic matter and organic carbon are variables of critical environmental importance in terms of soil productivity and function, global food security, and climate change mitigation. Rapid and accurate assessment of these variables is central to national programs and international agreements. Portable X-ray fluorescence instruments are widely used to rapidly quantify and map soil elements, however quantification of light elements that constitute the majority of organic materials is not yet possible with this technique (e.g. carbon). We developed a novel attachment for portable X-ray fluorescence instrumentation enabling concurrent volumetric soil organic matter and organic carbon quantification during PXRF analyses. This primary prototype outperformed more expensive visible-near infrared instrumentation using parsimonious soil specific simple linear regression (R2 ranged 0.85–0.97) enabling rapid, parallel, nondestructive, cost-effective acquisition of soil elemental concentrations together with soil organic carbon and soil organic matter data.

Total organic carbon quantification from wireline logging techniques: A case study in the Vaca Muerta Formation, Argentina

The Vaca Muerta Formation, one of the most prolific unconventional play in South America, exhibits concentrations of total organic carbon (TOC) of up to 16% with variations in TOC paralleling the general facies evolution of the prograding system. This study examines the applicability and accuracy of predicting TOC from two methods of quantifying organic-rich zones from wireline logs: the relationship of uranium from spectral gamma-ray to TOC, and the δlogR technique for calculating TOC.A database from extensive outcrop geochemical sampling (n = ~1900) was correlated to the uranium signal from a handheld spectral gamma-ray logging tool. The U/TOC relationship derived from the outcrop samples shows high variability between outcrop sections measured across the formation. The U/TOC ratio increases from proximal to distal positions within the basin.A second dataset, consisting of core samples, was also analyzed and compared to the TOC calculated using a combination of the sonic and resistivity data obtained from downhole logging. This second method of TOC prediction reliably and accurately reproduces laboratory measurements, and is the far superior choice when estimating organic richness from wireline log signatures. To further test this method of TOC prediction, a subset of sidewall plugs were analyzed for petrophysical and geochemical measurements and using the δlogR technique, was able to produce TOC values that compared to discrete laboratory measurements with a correlation coefficient of R2 = 0.83.The time-tested method of determining organic richness from wireline logs can be successfully applied in the Neuquén Basin and could be attempted in other basins once all available data has been carefully considered.

Microwave-assisted digestion employing diluted nitric acid for mineral determination in rice by ICP OES

A microwave-assisted digestion method using diluted HNO3 was developed for further determination of Al, Ca, Cr, Cu, Fe, K, Mn, Mo and Ni in rice samples by ICP OES. The following optimized conditions were established after full factorial design: digestion time of 14 min, concentration of 1 mol L−1 HNO3 and 2.5 mL of H2O2. The efficiency in decomposing organic matter with diluted acid was higher than 89%. The methodology was validated using the SRM NIST 1568a Rice Flour and recovery tests, with agreement between the determined and certified/added concentration values, and RSD of up to 12%. The limits of detection of the method were in the range of 0.0087 mg kg−1 (Mn) to 1.6 mg kg−1 (Ca). In addition, a simple and inexpensive spectrophotometric method was proposed for the quantification of organic carbon in varied samples (carbohydrates, proteins, lipids) in the form of digested or solids.

Mineralogical composition and total organic carbon quantification using x-ray fluorescence data from the Upper Cretaceous Eagle Ford Group in southern Texas

Six southern Texas Eagle Ford cores were investigated to quantify mineralogical composition and total organic carbon (TOC). Machine learning of the x-ray fluorescence (XRF) data set was conducted using neural network analysis to predict mineralogies for L1, L2, and L3 and TOC for L1, L2, L3, Iona-1, Innes-1, and well “X.” Inees-1 and well “X” were used as blind tests to check the quality of the developed models. The online Neural Designer software was used to perform the training process and develop models. Quantitative laboratory-measured x-ray diffraction (XRD) mineralogies and TOC were used to conduct the training and develop high-resolution semiquantitative models, and the derived mineralogic and organic matter models were found to be promising. The modeled mineralogy and TOC represent continuous relative abundances, which are far more significant than scattered individual XRD and TOC point measurements. The significance of this study is that it allows for the use of relatively inexpensive and nondestructive XRF analysis that requires minimal sample preparation to construct high-resolution mineral abundances and TOC content. With modern advances in technology, XRF can now be measured on drill cuttings in real time while drilling is occurring, allowing operators to use the proposed method to construct semiquantitative mineralogical and TOC models for evaluating placement of laterals in prospective intervals and designing completion techniques accordingly.

Abiotic synthesis of graphite in hydrothermal vents

Deciphering the origin, age, and composition of deep marine organic carbon remains a challenge in understanding the dynamics of the marine carbon cycle. In particular, the composition of aged organic carbon and what allows its persistence in the deep ocean and in sediment is unresolved. Here, we observe that both high and low temperature hydrothermal vents at the 9° 50′ N; 104° 17.5 W East Pacific Rise (EPR) vent field are a source for (sub)micron-sized graphite particles. We demonstrate that commonly applied analytical techniques for quantification of organic carbon detect graphite. These analyses thereby classify graphite as either dissolved or particulate organic carbon, depending on the particle size and filtration method, and overlook its relevance as a carbon source to the deep ocean. Settling velocity calculations indicate the potential for these (sub)micron particles to become entrained in the buoyant plume and distributed far from the vent fields. Thus, our observations provide direct evidence for hydrothermal vents acting as a source of old carbon to the deep ocean.

Quantification of organic carbon from biomass versus non-biomass burning emissions to fine aerosol

Quantification of organic carbon from biomass versus non-biomass burning emissions to fine aerosol

Improved method for removing siderite byin situacidification before elemental and isotope analysis of soil organic carbon

AbstractSiderite (FeCO3) is an iron carbonate mineral commonly found in sediments and soils. Similarly to other carbonates, such as calcite or dolomite, it may substantially affect the quantification of organic carbon (C) as well as determination of C isotope ratio of soil organic matter. Both analyses require effective removal of siderite by pretreatment with acid. However, little is known about the siderite removal efficiency of the acid pretreatment methods which have been previously proposed in the literature.In our study, we tested three previously proposed carbonate removal methods for siderite removal in siderite‐containing soils. Furthermore, we tested whether siderite C content in a soil sample can be detected as CO2evolved after H3PO4addition which would allow organic C determination from the difference between total and inorganic C.None of the three tested pretreatment methods led to sufficient removal of siderite C when applied on siderite alone. Therefore, we developed a new protocol for a 4‐day treatment with 10% HCl at 25°C. At siderite content of up to 10 wt.%, the removal efficiency of our method (99–100%) was sufficient both for organic C as well as for C isotope analyses. This was further confirmed with tests on siderite‐containing soils. These showed that the method ofLarsonet al. () developed for sediments is also suitable. However, the new protocol provides advantage in terms of less microplate manipulation, capsule overflow and oven use. We found that CO2is not evolved 2 minutes after H3PO4addition from siderite in contrast to calcite and dolomite. This fact can be used for separate quantification of inorganic C from calcite/dolomite and siderite,e.g., in studies of their different role in soil development. We showed that siderite‐containing soils require special pretreatment procedure before organic C and13C/12C analyses. We recommend using our protocol if techniques such as XRD or SEM‐EDS indicate the presence of siderite in soil.

Feasibility of coupling a thermal/optical carbon analyzer to a quadrupole mass spectrometer for enhanced PM2.5 speciation

ABSTRACTA thermal/optical carbon analyzer (TOA), normally used for quantification of organic carbon (OC) and elemental carbon (EC) in PM2.5 (fine particulate matter) speciation networks, was adapted to direct thermally evolved gases to an electron impact quadrupole mass spectrometer (QMS), creating a TOA-QMS. This approach produces spectra similar to those obtained by the Aerodyne aerosol mass spectrometer (AMS), but the ratios of the mass to charge (m/z) signals differ and must be remeasured using laboratory-generated standards. Linear relationships are found between TOA-QMS signals and ammonium (NH4+), nitrate (NO3−), and sulfate (SO42-) standards. For ambient samples, however, positive deviations are found for SO42-, compensated by negative deviations for NO3−, at higher concentrations. This indicates the utility of mixed-compound standards for calibration or separate calibration curves for low and high ion concentrations. The sum of the QMS signals across all m/z after removal of the NH4+, NO3−, and SO42- signals was highly correlated with the carbon content of oxalic acid (C₂H₂O₄) standards. For ambient samples, the OC derived from the TOA-QMS method was the same as the OC derived from the standard IMPROVE_A TOA method. This method has the potential to reduce complexity and costs for speciation networks, especially for highly polluted urban areas such as those in Asia and Africa.Implications: Ammonium, nitrate, and sulfate can be quantified by the same thermal evolution analysis applied to organic and elemental carbon. This holds the potential to replace multiple parallel filter samples and separate laboratory analyses with a single filter and a single analysis to account for a large portion of the PM2.5 mass concentration.

Quantification of organic carbon and primary nutrients in litter and soil in a foothill forest plantation of eastern Himalaya

The present study was an effort to understand the amount of litter fall and its subsequent decomposition and quantify the release of available nutrients and soil physicochemical characteristics in plantations of four forest tree species (Lagerstroemia parviflora, Tectona grandis, Shorea robusta and Michelia champaca) in the Chilapatta Reserve Forest of the Cooch Behar Wildlife Division in the Terai zone of West Bengal, India. The most litter (5.61 Mg ha−1) was produced by T. grandis plantation and the least (4.72 Mg ha−1) by L. parviflora. The material turnover rate to the soil through decomposition from total litter was fastest during the first quarter of the year and subsequently decreased during the next two quarters. The material turnover rate was only 1 year, which indicates that more than 90% of the total litter produced decomposed within a year. The available primary nutrient content in litter varied across the four plantations over the year. The plantations generally did not significantly influence the soil physical characteristics but did significantly influence the availability of primary nutrients and organic carbon at two depths (1–15 and 16–30 cm) over the year. The availability of soil primary nutrients in the four plantations also increased gradually from the first quarter of the year to the third quarter and then decreased during the last quarter to the same level as in the first quarter of the year at both depths. The availability for soil organic carbon in the plantations followed a similar trend. The amount of litter produced and the material turnover in the soil in the different plantations differed, influencing the nutrient availability and organic carbon at the plantations. The amount of soil organic carbon was highest for T. grandis (2.52 Mg ha−1) and lowest for L. parviflora (2.12 Mg ha−1). Litter is the source of soil organic matter, and more the litter that is produced by the plantations, the higher will be the content and amount of soil organic carbon in the plantation.

Genesis and properties of wetland soils by VIS-NIR-SWIR as a technique for environmental monitoring

Wetlands are important ecosystems characterized by redoximorphic environments producing typical soil forming processes and organic carbon accumulation. Assessments and management of these areas are dependent on knowledge about soil characteristics and variability. By reflectance spectroscopy, information about soils can be obtained since their spectral behaviors are directly related to their chemical, physical, and mineralogical properties reflecting the pedogenetic processes and environment conditions. Our aims were: (a) to characterize the main soil classes of wetlands regarding their spectral behaviors in VIS-NIR-SWIR (350–2500 nm) and relate them to pedogenesis and environmental conditions, (b) to determine spectral ranges (bands) with greater expression of the main soil properties, (c) to identify spectral variations and similarities between hydromorphic soils from wetlands and other soils under different moisture conditions, and (d) to propose spectral models to quantify some chemical and physical soil properties used as environmental quality indicators. Nine soil profiles from the Pantanal region (Mato Grosso State, Brazil) and one from the Serra do Espinhaço Meridional (Minas Gerais State, Brazil) were investigated. Spectral morphology interpretation allowed identifying horizon differences regarding shape, absorption features and reflectance intensity. Some pedogenetic processes of wetland soils related to organic carbon accumulation and oxide iron variation were identified by spectra. Principal Component Analysis allowed discriminating soils from wetland and outside this area (oxidic environment). Quantification of organic carbon was possible with R2 of 0.90 and low error. Quantification of clay content was masked by soils with organic carbon content over 2% where it was not possible to quantify with high R2 and low error both properties when dataset has soil samples with high organic carbon content. By reflectance spectroscopy, important characteristics of wetland soils can be identified and used to distinguish from soils of different environments at low costs, reduced time, and with environmental quality.