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2 Predictive soil-regolith toposequence model showing soil-water-landscape changes in the southern Mesopotamian marshlands from 3000 BCE to 2003 CE (present) (Modified from Fitzpatrick 2004b). *Notations BCE (before common era) = BC and CE (common era) = AD
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Classifying soils for a particular purpose involves the ordering of soils into groups with similar properties and for potential end uses. The classification of soil is a terrific conceptual and practical challenge, especially in arid environments. The challenge may spur on, or it may deter scientists or end users with an interest in soils. If a cla...
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... When combined with site-specific observations, this framework could serve as a starting point for stratifying fields into zones for soil health test sampling. In contrast, general-purpose soil classification systems such as the US Soil Taxonomy and the World Reference Base (IUSS Working Group WRB, 2022; Soil Survey Staff, 1999) provide a standardized way for communicating about soils but require more expertise to interpret and use (Fitzpatrick, 2013). An advantage of the clustering approach used in the present study is that it can be applied at different scales and other regions thanks to the availability of large public databases like the US SSURGO or the European Union Land Use/Land Cover Area frame Survey (LUCAS) to provide input data (USDA-NRCS, 2021;Tóth et al., 2013). ...
... Different soil properties can be incorporated into the analysis based on key soil features or resource concerns relevant to the AOI. We view the cluster-based method for grouping soils presented here as one example of a special-purpose soil classification system (Fitzpatrick, 2013); such systems can add value by providing user-friendly ways to use soil information and complementing existing systems such as MLRA and soil taxonomy (Grealish et al., 2015). ...
Soil health assessments aim to quantify soil health status using indicators linked to ecosystem services such as yield, nutrient cycling, water cycling, or carbon storage. Many indicators are related to soil biological processes, which can be challenging to interpret because they are sensitive not only to management, but also to nonmanagement variables such as soil inherent properties, topography, and climate. Existing studies address this challenge by grouping similar soils by taxonomy, geography, or a combination of these and other variables for soil health assessment. We investigated whether grouping soils based on multiple quantitative topsoil properties could be an alternative to taxonomic or geographic groups. We used an unsupervised classification algorithm, k‐means, to cluster publicly available soil and climate data for Minnesota. Clustering into eight conceptual groups (“clusters”) based on 10 topsoil properties was determined to be the optimal algorithm output. We evaluated the ability of our soil clusters and other grouping methods to explain variance in eight soil health indicators. We found the combination of Major Land Resource Area (MLRA) and soil cluster performed best, explaining as much or more variance than other groupings for five of the eight indicators. The clusters distinguish zones of topsoil variation at the field scale, and MLRAs account for broader scale variation in climate and other landscape factors. The approach we describe is flexible and could be applied at different locations and scales to produce conceptual soil groups and associated maps to support soil health test sampling and interpretation at the field scale.
... The general definition of ASS has, in the past, encompassed potential acid sulfate soils (PASS), active (or actual) acid sulfate soils (AASS), and post-active acid sulfate soils (e.g., Fanning et al. 2017). Nevertheless, because these terms are not commonly defined or used in national or international soil classification systems, and to avoid potential confusion arising from these broad ASS types, the terms "sulfuric soils" and "hypersulfidic soils" have recently been introduced to be used instead of "active acid sulfate soils" and "potential acid sulfate soils", respectively (e.g., Fitzpatrick 2013;Fitzpatrick et al. 2017a). In this paper, we adopt these refined terms. ...
Established international soil classification systems have not properly accommodated acid sulfate soils (ASS) and soil materials in Finland and Sweden because: (1) in these soils some diagnostic ASS properties are too deep to meet the depth requirements, and (2) there is a lack of defined diagnostic soil classification criteria for acidic and potentially acidic soil materials that do not completely fulfill the diagnostic pH-criterion of pH < 4.0. In this paper, two new ASS materials are introduced with the prefix “para” for parasulfuric material (oxidized material) and parahypersulfidic material (reduced material). These materials have diagnostic pH-criteria of pH 4.0–4.5 and 3.0–3.5 (field-pH for parasulfuric material and incubation-pH for parahypersulfidic material) for mineral and organic soil materials (here defined as > 20% organic matter; peat and gyttja), respectively. The term “para-acid sulfate soil (para-ASS) material” is introduced for soil materials which may have a considerable environmental impact due to mobilization of acidity and dissolved metals. Because organic acids may lower pH to values below the established pH-value of < 4.0 for ASS materials, a pH of < 3.0 is used in the Finnish-Swedish ASS classification for organic soil materials. These changes and new additions to existing diagnostic ASS materials have consequently also led to a slight modification of the required field-pH values of the existing terms “hypersulfidic material” and “sulfuric material”. The Finnish-Swedish ASS classification further includes a systematic way for classification of the entire soil profile and no depth requirements for diagnostic ASS materials are present; what matters is the current or potential environmental impact that the soil has or may have. It is proposed that the Finnish-Swedish ASS classification may serve as a framework for establishing a unified ASS classification globally and that the new diagnostic ASS materials are included in relevant international soil classification systems.
... They demonstrated that pedogenons can be identified using soil-forming spatial layers. It is beneficial not to use an established classification system because the established system is commonly based on soil attributes that may result from either natural processes or human activities (Fitzpatrick, 2013). ...
Mapping soil classes can support the understanding of soil origin and development, subsequently the soil classes can be used to support monitoring and assessing soil change due to human influence. Pedogenon was proposed as a conceptual soil taxon derived from a set of quantitative state variables representing the soil-forming factors for a given reference time. This study aims to test the pedogenon concept in the Edgeroi region in New South Wales. This paper developed local pedogenons, designed a sampling scheme to capture soil variation under natural conditions and under intensive human activities, and tested the hypothesis that pedogenon is an efficient method of stratifying the landscape to capture soil variation. This study derived the 14 pedogenons by employing layers of soil-forming factors (soil, climate, organism, topography, and parent material and age) using an unsupervised classification technique (k-means clustering). Within each pedogenon, genosoils were identified based on areas with native vegetation, while phenosoils were identified as areas with cropping practises. One meter soil cores were collected for each genosoil and phenosoil, and scanned using Vis-NIR spectrometer for predicting soil properties (clay, sand, cation exchange capacity, pH, and organic carbon). Results show that each pedogenon was characterised by a soil type formed under a dominant parent material occupying a unique position in the landscape. Redundancy discriminant analysis of the soil properties as a function of pedogenon and depth of observations show that pedogenon significantly explained the variation in soil properties. Variance partitioning analysis confirmed that pedogenon explained a large proportion of the variation (49 %) as opposed to landuse (5 %). Principal component analysis of the soil properties shows that genosoils had twice the variation of phenosoils. The results indicate that agricultural activities homogenised the variation of soil profiles. This study demonstrated that pedogenon clasess can effectively characterise soil variation and be used as a benchmark to compare how human activities have altered soil conditions.
... Barapalli series (P5) developed near to coastal seashores and direct effect of tidal movement of seawater; the soil is very deep, dull yellowish-brown color, silty clay texture, and sluggish nature of lower layers. Coastal undulated toposequence models are providing information on soil formation (Sommer et al. 2001), water movement (Pachepsky et al. 2006), soil-regolith process (Fritsch and Fitzpatrick 1994), and land degradation (Fitzpatrick 2013). ...
Rice cultivation widely distributed in Southeast Asia on gently sloping coastal plains with different toposequences and elevation. These toposequences, slope differences primarily due to differentiation in soil development and water movement are key to rice production. Understanding soil variables under rice cultivation along the different toposequence models in coastal systems is rarely an attempt toward sustainable crop productivity. With the objectives of investigating variation in soil properties under rice cultivation along the toposequences in the eastern coastal part of Odisha, five soil series representing alluvial (old and young), colluvium, and coastal plain (plain and shore) toposequences were studied that are classified into two soil orders viz. Inceptisols (P1, P2, P4, and P5) and Vertisols (P3). The soils are deep to very deep, poor to moderately well-drained, color varied from brown to dark gray. The clay content varied from 12.6 to 81.4%. High clay content (> 60%) was observed in subsoils of colluvium (P3) and young alluvial plain (P2). Soil reaction varied from slightly acidic to moderately alkaline (pH 6.2–9.4) and electrical conductivity (EC) was ranging from 0.23 to 5.60 dS m−1. OC content was low to high (0.12–1.13%) and CEC and base saturation (BS) ranged from 4.9 to 37.1 cmol (p+) kg−1 and 73–95%, respectively. Rice soils suffer from different nutrient deficiencies (N, P, and Zn) and toxicities (Fe, Mn, and Cu) in different root zone depths in slope position. Variation in rice yield was highly significant with clay content, CEC, and negatively correlated with EC, Exchangeable sodium, and ESP. Linear regression of rice yield with soil properties R2 values varied from 0.29 (ESP) to 0.40 (CEC). Water movement and alternate wet and dry rice cultivation systems impact clay deposition, anion, and cation movement along the toposequence. Moreover, OC and K were increased down the slope on the coastal plain than alluvial soils. Conceptual toposequence model exhibition of the landscape is key to find major soils at the family level and crop response in the coastal systems. Thus, adopting site-specific or soil-based suitable management practices can improve the productivity of rice crops.
... The soil profile is classified as a sulfuric (pH < 4) soil in accordance with the Australian acid sulfate soil classification key (Fitzpatrick, 2013). Based on the Australian Soil Classification (Isbell and National Committee on Soil and Terrain, 2016) and WRB identification keys (IUSS Working Group WRB, 2014) the soil profile is classified as a Peaty, Sulfuric, Hypersalic Hydrosol and Salic Fluvisol (Hyperthionic, Drainic), respectively. ...
Acid sulfate soils contain hypersulfidic material, e.g. pyrite (FeS2). Under oxidizing conditions, it transforms to sulfuric material (pH < 4), which is accompanied with the formation of jarosite [KFe3(SO4)2(OH)6] along root channels (designated as jarositic phyto tubules). The encapsulation of root residues with jarosite can lead to reduced spatial availability of organic carbon which is necessary as substrate for microbes. This can limit microbial activity which might be crucial for prospective remediation success. We investigated jarositic phyto tubules by combining X-ray computed microtomography (µCT) and nanoscale secondary ion mass spectrometry (NanoSIMS), to elucidate the porosity and organic matter distribution at the spatial scale most relevant for microbial processes.
We demonstrated that the jarosite can be differentiated into zones with either high or low jarosite concentrations at distances of < 0.5 mm and 0.5–1.9 mm from the relict root channel, respectively. The results showed a closer association between jarosite and organic matter in the zone with high jarosite concentration. However, the pore space in immediate vicinity of the root is almost completely filled by jarosite and the organic matter is completely encapsulated. We conclude that the overall poor accessibility of organic matter will strongly retard remediation processes of sulfuric soils after re-submergence.
... In this "Anthropocene Era", one of the roles of soil scientists for the sustainable development goals is to assess the quality of our soils and attempt to foresee the best soil management for both environmental and human protection [30]. Soil research has largely increased the possibility to improve soil quality through controlled soil development of Technosols. ...
The study of Technosols development, spatial distribution and physicochemical characteristics is becoming more and more important in the Anthropocene Era. The aim of the present study was to assess soil features and potential heavy metal release risk of soils developed on different mine tailing types after the waste disposal derived from mining activity in Central Italy. Soils were analyzed for their morphological, physical and chemical properties, and a chemical sequential extraction of heavy metals was performed. The investigated soils were classified as Technosols toxic having in some layer within 50 cm of the soil surface inorganic materials with high concentrations of toxic elements. Our findings showed that the bioavailability of potentially toxic element concentrations in the soil changed according to the origin of the mine tailing. However, because of the acidic pH, there is a serious risk of metals leaching which was reduced where the soil organic matter content was higher.
... They are wide-spread throughout the world in coastal and inland areas, e.g. in southern Australia (Fanning et al., 2017). Upon aeration, oxidation of Fe sulfides (principally pyrite) causes strong acidification when insufficient acid neutralising capacity is present, the resulting soils are commonly referred to as acid sulfate soils with sulfuric material (pH <4) or sulfuric soils (Fitzpatrick, 2013). Some of the major environmental hazards associated with acidification of soils and waters are aluminium toxicity, trace metal/metalloid mobilization, and de-vegetation. ...
... Pale yellow jarosite mottles formed along relict mangrove roots and pneumatophore channels. The soil was classified as sulfuric soil in accordance with the Australian acid sulfate soil classification (Fitzpatrick, 2013). According to the Australian Soil Classification (Isbell and National Committee on Soils and Terrain, 2016), the soil was classified as Peaty, Sulfuric, Hypersalic Hydrosol, and as Salic Fluvisol (Hyperthionic, Drainic) according to WRB identification keys (IUSS Working Group WRB, 2015). ...
Aeration of wetland soils containing iron (Fe) sulfides can cause strong acidification due to the generation of large amounts of sulfuric acid and formation of Fe oxyhydroxy sulfate phases such as jarosite. Remediation by re-establishment of anoxic conditions promotes jarosite transformation to Fe oxyhydroxides and/or Fe sulfides, but the driving conditions and mechanisms are largely unresolved. We investigated a sandy, jarosite-containing soil (initial pH = 3.0, Eh ~600 mV) in a laboratory incubation experiment under submerged conditions, either with or without wheat straw addition. Additionally, a model soil composed of synthesized jarosite mixed with quartz sand was used. Eh and pH values were monitored weekly. Solution concentrations of total dissolved organic carbon, Fe, S, and K as well as proportions of Fe²⁺ and SO4²⁻ were analysed at the end of the experiment. Sequential Fe extraction, X-ray diffraction, and Mössbauer spectroscopy were used to characterize the mineral composition of the soils. Only when straw was added to natural and artificial sulfuric soils, the pH increased up to 6.5, and Eh decreased to approx. 0 mV. The release of Fe (mainly Fe²⁺), K, and S (mainly SO4²⁻) into the soil solution indicated redox- and pH-induced dissolution of jarosite. Mineralogical analyses confirmed jarosite losses in both soils. While lepidocrocite formed in the natural sulfuric soil, goethite was formed in the artificial sulfuric soil. Both soils showed also increases in non-sulfidized, probably organically associated Fe²⁺/Fe³⁺, but no (re-)formation of Fe sulfides. Unlike Fe sulfides, the formed Fe oxyhydroxides are not prone to support re-acidification in the case of future aeration. Thus, inducing moderately reductive conditions by controlled supply of organic matter could be a promising way for remediation of soils and sediments acidified by oxidation of sulfuric materials.
... The area where the soil was collected was covered with mangrove forest before it was drained and then acidified. The soil profile is classified as sulfuric soil according to Australian acid sulfate soil classification (Fitzpatrick 2013) and Hypothionic Gleysol (Drainic, Hypersulfidic) according to the World Reference Base for Soil Resources (for detailed information, see Table 1). Sulfuric material was taken at a depth of 80-150 cm in a trench that allowed direct access to this depth. ...
The purpose of this study is to determine the effect of pH, soil water content, and organic matter availability on soil P pools and Fe minerals in acid sulfate soils which are common in coastal areas and paddy rice fields. An acid sulfate soil (original pH 3.2 or adjusted to pH 5.5) was amended with mangrove root pieces to achieve an organic carbon addition of 50% or 150% of native soil organic carbon. Then, the soil was incubated for 12 weeks with 4 weeks each in submerged, and then moist and then again submerged conditions. At the end of each 4-week period, soil P pools (labile P, moderately labile P, non-labile P, and residual P), oxalate extractable Fe/Al, and potential phosphate P sorption were measured. During the submerged periods, addition of mangrove roots decreased the redox potential and increased oxalate extractable Fe, but only at pH 5.5, indicating that reducing microbes were constrained by the low pH of the original soil. Labile phosphate was up to twofold higher with mangrove roots than in the unamended control, with greatest increase at 150% OC and pH 5.5. The increase in labile phosphate was likely due to release of bound P by Fe reduction and of P released from mangrove roots. Mangrove root addition enhanced phosphate sorption during the first 8 weeks, suggesting that mangrove roots provided more P binding sites in cell walls. Raising the pH to 5.5 and addition of organic matter can enhance P availability in acid sulfate soils by providing P and enhancing soil P release.
... Since it covers broad range of details and closely related to other disciplines, it overlaps with few other fundamental sciences. One of it is forensic soil science which is a study of soil to solve judicial problems or hypotheses (Fitzpatrick 2013). ...
... Other than that, it composed organic matters which consist of living microbiota and humus, roots of plants, decomposed plants and remains of animal (Dawson & Hillier 2010). Complicated biological, chemical, physical, mineralogical and hydrological properties also possessed by soil which is subject to change over the time (Fitzpatrick 2013). ...
Soil sample is one of the important evidence that can be found in crime scene. Unknown soil sample can be analysed and compared with reference sample in order to determine the origin as its physical and chemical components possess unique characteristics. The purpose of this study is to determine the physical and chemical characteristics of soil from oil palm plantations in Perak, Malaysia to assist forensic investigation. Total of 97 topsoil samples were collected from three different oil palm plantations in Perak. Particle size distribution was obtained using dry sieving technique and colour of soil sample was examined under three conditions that are dry, moist and ashed. Soil pH was measured using pH meter and percentage of composition of soil organic matter (SOM) was determined by weighing the sample before and after ignition. Result showed that the composition of particle size <0.18mm was within the range of 5.57-21.11% whereas for particle size between 0.18mm - 0.6mm was within 31.62 - 52.96% and 25.78-66.86% for particle size >0.6mm. The color mode of soil after oven dried, moistened and ashed was greyish brown (10YR 5/2), very dark greyish brown (10YR 3/2) and light yellowish brown (10YR 6/4) respectively. Soil pH was in the range of 5.79 – 6.70. The percentage of SOM was between 3.29 - 20.48%. The physical and chemical characteristics of soil analysed in this study from three different locations of oil palm plantations varied and it is possible to discriminate these locations based on the analysis highlighted in this study.
... MATERIALS AND METHODS Soil. The sulfidic soil used, collected from a 'sulfuric subaqueous clayey soil' [14] at a depth of ca. 1 m in the Finniss River (Fig. 2), Adelaide, South Australia (35°24028.28″ S, 138°49054.37″ ...
Managing the surface soil (0−10 mm) is important for microbes and benthic organisms that regulate various ecological services, e.g. regulation of soil or water chemistry, oxygenation, and temperature. In this study, the importance of soil carbon and nitrogen in the subsurface (10-80 mm) of sulfidic soil was investigated following the addition of complex and simple carbon and nitrogen sources. The purpose was to assess the effects of carbon and nitrogen on sulfidic soil chemistry (i.e. redox and pH) so as to establish alternative management strategies to prevent oxidation of the surface soil. Aerobic and anaerobic soil moisture conditions were considered as the most prevalent under any surface environment. The results showed that the presence of both carbon and nitrogen, either under aerobic or anaerobic soil condition, is important to prevent oxidation. Organic matter of plant material origin is complex and contains both carbon and nitrogen; this highly reduces the soil redox and increases the pH, even under the aerobic soil conditions. Simple metabolic substrate like glucose acidified the soil and ammonium had no significant effect on soil pH compared to compounds like urea containing both carbon and nitrogen having the opposite effects. The results of this study have implications for management of the surface soil, which is important for various surface environment chemistry and ecosystem services.
