Title: Gradients of geochemical change in relic charcoal hearth soils, Northwestern Connecticut, USA
Relic charcoal hearths (RCHs) have produced distinct legacy effects in forest soils around the world. Recently, LiDAR imagery has revealed thousands of 18th–early 20th century RCHs in Litchfield County, Connecticut, USA; however, the effects of RCHs on a landscape-scale are not well-documented, particularly fine-scale heterogeneity within RCHs and surrounding soils. This study examines the long-term impacts of charcoal production by measuring RCH soil chemical and physical properties from three perspectives: (1) compared to adjacent reference sites (RSadj), (2) laterally at systematic distances away from the RCH center, and (3) vertically within the RCH soil profile. Mean charcoal abundance was greater in RCH sites than RSadj (p < 0.01). Soil organic carbon (SOC), total C, and extractable Ca2+, Mg2+, Na+ were greater in RCH sites as compared to RSadj (p < 0.01), and available phosphorus (p < 0.01), K+, and trace elements (Mo, Ag, Hg, and Se) were lower (p < 0.05). In vertical profiles, many RCHs had 2 charcoal-rich layers within the anthropic epipedon, demonstrating multiple episodes of charcoal production. Peaks in SOC, C:N, Ca2+, Mg2+ corresponded with charcoal-rich layers. Systematic transect sampling across the RCH boundary identified charcoal fragments in soils at distances up to 25 m beyond the RCH boundary, increasing the surface-level (0–15 cm) area of impact for an individual RCH by more than 30×, from a 5-m radius (RCH area = 78.5 m2) to a 30-m radius (total area of impact = 2826 m2). These findings capture fine-scale variations within and among RCH and reference sites and contribute to estimating the total area of forest soils impacted by historical charcoal production. more »« less
Relict charcoal hearths (RCHs) are anthropogenic geomorphic features with an average diameter of 12 m found in many forests of Central Europe and in the eastern USA wherever pre-coal iron production took place or other industries demanded the production of charcoal. To expand the knowledge about their geoarchaeological significance and their legacy effect on soil properties and forest ecosystems, we propose a method for a generalized description of soil stratigraphy on RCHs. We studied 154 soil profiles at 52 RCH sites alongside two 1 km transects in Litchfield County, Connecticut, USA. The sites can be classified based on the slope inclination, with sites on <4° mostly having a single-layered stratigraphy and an elevated circular shape, while sites on slopes >4° mostly are built as levelled and multilayered platforms. The latter have two or more charcoal rich technogenic Auh-layers separated by intermediate Auh-layers mostly consisting of mineral substrate. Based on average layer thicknesses and their dependence on the sites slope inclinations, we propose a model with two idealized RCH shapes with slope controlled properties that allow for an easy computation of site diameters and elemental stocks. With ongoing advances in remote sensing of RCH sites, our proposed model can help to further understand the effects of historic land use on a landscape scale.
Mauclet, Elisabeth; Villani, Maëlle; Monhonval, Arthur; Hirst, Catherine; Schuur, Edward_A G; Opfergelt, Sophie
(, Earth System Science Data)
Abstract. Permafrost ecosystems are limited in nutrients forvegetation development and constrain the biological activity to the activelayer. Upon Arctic warming, permafrost thaw exposes large amounts of soilorganic carbon (SOC) to decomposition and minerals to weathering but alsoreleases organic and mineral soil material that may directly influence thesoil exchange properties (cation exchange capacity, CEC, and base saturation,BS). The soil exchange properties are key for nutrient base cation supply(Ca2+, K+, Mg2+, and Na+) for vegetation growth anddevelopment. In this study, we investigate the distributions of soil exchangeproperties within Arctic tundra permafrost soils at Eight Mile Lake(Interior Alaska, USA) because they will dictate the potential reservoir ofnewly thawed nutrients and thereby influence soil biological activity andvegetation nutrient sources. Our results highlight much lower CEC density insurface horizons (∼9400 cmolc m−3) than in the mineralhorizons of the active layer (∼16 000 cmolc m−3)or in permafrost soil horizons (∼12 000 cmolc m−3). Together, with the overall increase in CEC density with depth andthe overall increase in BS (percentage of CEC occupied by exchangeable basecations Ca2+, K+, Mg2+, and Na+) with depth (from∼19 % in organic surface horizons to 62 % in permafrost soilhorizons), the total exchangeable base cation density (Ca2+, K+,Mg2+, and Na+ in g m−3) is up to 5 times higher in thepermafrost than in the active layer. More specifically, the exchangeablebase cation density in the 20 cm upper part of permafrost about to thaw is∼850 g m−3 for Caexch, 45 g m−3 forKexch, 200 g m−3 for Mgexch, and 150 g m−3 forNaexch. This estimate is needed for future ecosystem prediction modelsto provide constraints on the size of the reservoir in exchangeablenutrients (Ca, K, Mg, and Na) about to thaw. All data described in this paper are stored in Dataverse, the online repository of Université catholique de Louvain, and are accessible through the following DOI: https://doi.org/10.14428/DVN/FQVMEP (Mauclet et al., 2022b).
Malhotra, Avni; Moore, Jessica_A M; Weintraub-Leff, Samantha; Georgiou, Katerina; Berhe, Asmeret Asefaw; Billings, Sharon A; de_Graaff, Marie-Anne; Fraterrigo, Jennifer M; Grandy, A Stuart; Kyker-Snowman, Emily; et al
(, Communications Earth & Environment)
Abstract Increasing fine root carbon (FRC) inputs into soils has been proposed as a solution to increasing soil organic carbon (SOC). However, FRC inputs can also enhance SOC loss through priming. Here, we tested the broad-scale relationships between SOC and FRC at 43 sites across the US National Ecological Observatory Network. We found that SOC and FRC stocks were positively related with an across-ecosystem slope of 7 ± 3 kg SOC m−2per kg FRC m−2, but this relationship was driven by grasslands. Grasslands had double the across-ecosystem slope while forest FRC and SOC were unrelated. Furthermore, deep grassland soils primarily showed net SOC accrual relative to FRC input. Conversely, forests had high variability in whether FRC inputs were related to net SOC priming or accrual. We conclude that while FRC increases could lead to increased SOC in grasslands, especially at depth, the FRC-SOC relationship remains difficult to characterize in forests.
Pingree, Melissa RA; Makoto, Kobayashi; DeLuca, Thomas
(, Biology and fertility of soils)
The purpose of this study was to assess the effects of charcoal and earthworm presence in contrasting soil types of northern Japan using the biologically based phosphorus (BBP) extraction method, which employs a variety of plant P acquisition strategies. Using soils developed in serpentine and sedimentary parent materials, we tested the interactive effects of Eisenia japonica (Michaelsen) earthworms and 500 kg ha−1 of dwarf bamboo charcoal (Sasa kurilensis (Rupr.) Makino et Shibata) in a microcosm incubation that lasted four weeks. Soils were extracted in parallel after the incubation with the BBP method using 0.01 M CaCl2 (soluble P), 0.01 M citric acid (chelate-extractable P), 0.02 phosphatase enzyme units ml−1 (enzyme-extractable organic P), and 1.0 M HCl (mineral occluded P). Dwarf bamboo charcoal alone contained up to 444 mg total BBP kg−1 prior to application to soil microcosms. Treatment effects in soil microcosms were highest in sedimentary soil types and where charcoal was combined with earthworms (15.97 mg P kg−1 ± SE 1.23 total inorganic BBP). Recalcitrant inorganic P (HCl extracted) in combination treatments yielded the highest single inorganic BBP measure (12.41 mg kg−1 ± SE 1.11). Our findings suggest that charcoal, as a legacy of wildfire, and native earthworm activity may help stimulate cycling of recalcitrant inorganic BBP pools.
Groffman, Peter M; Raciti, Steve
(, Environmental Data Initiative)
Abstract: One-meter soil cores were taken to evaluate soil texture, bulk density, carbon and nitrogen pools, microbial biomass carbon and nitrogen content, microbial respiration, potential net nitrogen mineralization, potential net nitrification and inorganic nitrogen pools in 32 residential home lawns that differed by previous land use and age, but had similar soil types. These were compared to soils from 8 forested reference sites. Purpose: Soil cores were obtained from residential and forest sites in the Baltimore, MD USA metropolitan area. The residential sites were mostly within the Gwynns Falls Watershed (-76.012008W, -77.314183E, 39.724847N, 38.708367S and approximately 17 km2) Lawns on residential sites were dominated by a variety of cool season turfgrasses. Forest soil cores were taken from permanent forest plots of the Baltimore Ecosystem Study (BES) LTER (Groffman et al. 2006). These remnant forests are over 100 years old with soils that were comparable in type and texture to those underlying the residential study sites. Soils from all sites were from the Manor series (coarse-loamy, micaceous, mesic Typic Dystrudepts), which are well-drained upland soils with loamy textures and bedrock at 5 to 10 feet below the soil surface. To aid the site selection process we used neighborhoods in the Baltimore City metropolitan area that have been mapped using HERCULES, a high resolution land cover classification system designed to assist in the study of human-ecological systems (Cadenasso et al. 2007). Using HERCULES and additional data sources, we identified residential sites that were similar except for single factors that we hypothesized to be important predictors of ecosystem dynamics. These factors included land use history (agriculture and forest, n = 10 and n = 22), housing density (low and medium/high, n = 9 and n = 23), and housing age (4 to 58 yrs old, n = 32). Housing age was acquired from the Maryland Property View database. Prior land use was determined based on land use change maps developed by integrating aerial photos from 1938, 1957, 1971, and 1999 into a geographic information system. Once a list of residential parcels meeting the predefined criteria were identified, we sent mailings to property owners chosen at random from each of the factor groups with the goal of recruiting 40 property owners for a 3 year study (of which this work is a part). We had recruited 32 property owners at the time that soil cores were obtained. Data have been published in Raciti et al. (2011a, 2011b) References Cadenasso, M. L., S. T. A. Pickett, and K. Schwarz. 2007. Spatial heterogeneity in urban ecosystems: reconceptualizing land cover and a framework for classification. Frontiers in Ecology and the Environment 5:80-88. Groffman, P. M., R. V. Pouyat, M. L. Cadenasso, W. C. Zipperer, K. Szlavecz, I. D. Yesilonis, L. E. Band, and G. S. Brush. 2006. Land use context and natural soil controls on plant community composition and soil nitrogen and carbon dynamics in urban and rural forests. Forest Ecology and Management 236:177-192. Raciti, S. R., P. M. Groffman, J. C. Jenkins, R. V. Pouyat, and T. J. Fahey. 2011a. Controls on nitrate production and availability in residential soils. Ecological Applications:In press. Raciti, S. R., P. M. Groffman, J. C. Jenkins, R. V. Pouyat, T. J. Fahey, M. L. Cadenasso, and S. T. A. Pickett. 2011b. Accumulation of carbon and nitrogen in residential soils with different land use histories. Ecosystems 14:287-297.
Donovan, S. Gradients of geochemical change in relic charcoal hearth soils, Northwestern Connecticut, USA. Retrieved from https://par.nsf.gov/biblio/10269850. Catena 197. Web. doi:https://doi.org/10.1016/j.catena.2020.104991.
@article{osti_10269850,
place = {Country unknown/Code not available},
title = {Gradients of geochemical change in relic charcoal hearth soils, Northwestern Connecticut, USA},
url = {https://par.nsf.gov/biblio/10269850},
DOI = {https://doi.org/10.1016/j.catena.2020.104991},
abstractNote = {Relic charcoal hearths (RCHs) have produced distinct legacy effects in forest soils around the world. Recently, LiDAR imagery has revealed thousands of 18th–early 20th century RCHs in Litchfield County, Connecticut, USA; however, the effects of RCHs on a landscape-scale are not well-documented, particularly fine-scale heterogeneity within RCHs and surrounding soils. This study examines the long-term impacts of charcoal production by measuring RCH soil chemical and physical properties from three perspectives: (1) compared to adjacent reference sites (RSadj), (2) laterally at systematic distances away from the RCH center, and (3) vertically within the RCH soil profile. Mean charcoal abundance was greater in RCH sites than RSadj (p < 0.01). Soil organic carbon (SOC), total C, and extractable Ca2+, Mg2+, Na+ were greater in RCH sites as compared to RSadj (p < 0.01), and available phosphorus (p < 0.01), K+, and trace elements (Mo, Ag, Hg, and Se) were lower (p < 0.05). In vertical profiles, many RCHs had 2 charcoal-rich layers within the anthropic epipedon, demonstrating multiple episodes of charcoal production. Peaks in SOC, C:N, Ca2+, Mg2+ corresponded with charcoal-rich layers. Systematic transect sampling across the RCH boundary identified charcoal fragments in soils at distances up to 25 m beyond the RCH boundary, increasing the surface-level (0–15 cm) area of impact for an individual RCH by more than 30×, from a 5-m radius (RCH area = 78.5 m2) to a 30-m radius (total area of impact = 2826 m2). These findings capture fine-scale variations within and among RCH and reference sites and contribute to estimating the total area of forest soils impacted by historical charcoal production.},
journal = {Catena},
volume = {197},
author = {Donovan, S.},
editor = {null}
}
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