Soil development rates from an optically stimulated luminescence-dated beach ridge sequence in Northern Jutland, Denmark

2010 ◽  
Vol 90 (2) ◽  
pp. 295-307 ◽  
Author(s):  
A H Nielsen ◽  
B. Elberling ◽  
M. Pejrup

Rates of podzolic soil development in sandy, temperate soils were quantified based on 14 soil pedons with five substrata from a beach ridge chronosequence near Jerup, Northern Denmark (57°N). Soil pH, organic carbon (C) as well as extractable iron (Fe) and aluminium (Al) were measured. The age of each pedon and soil stratum was measured by optically stimulated luminescence (OSL) dating and used to estimate soil development rates. Soils were divided into five groups from Typic Haplorthods and Entic Alorthods with a mean OSL age of 2965 ± 294 yr to Typic Quartzipsamments with a mean OSL age of 22 ± 11 yr. Acidification rates during the first 200 yr were ~1.9 pH units per 100 yr in the A horizons and C-sequestration rates were ~25 g C m-2 yr-1 (excluding litter accumulation). After ~1500 yr, the mineral soil C stocks stabilised around 13.0 ± 2.0 kg C m-2. Translocation rates of Al into B horizons were ~0.3 kg Al m-2 per 1000 yr, while translocation rates for Fe were scattered. Our study illustrates the potential of OSL dating in chronosequence studies to quantify soil development rates.Key words: Soil development rates, chronosequence, OSL-dating, C-sequestration rates and translocation rates

2018 ◽  
Vol 115 (11) ◽  
pp. 2776-2781 ◽  
Author(s):  
Lucas E. Nave ◽  
Grant M. Domke ◽  
Kathryn L. Hofmeister ◽  
Umakant Mishra ◽  
Charles H. Perry ◽  
...  

Soils are Earth’s largest terrestrial carbon (C) pool, and their responsiveness to land use and management make them appealing targets for strategies to enhance C sequestration. Numerous studies have identified practices that increase soil C, but their inferences are often based on limited data extrapolated over large areas. Here, we combine 15,000 observations from two national-level databases with remote sensing information to address the impacts of reforestation on the sequestration of C in topsoils (uppermost mineral soil horizons). We quantify C stocks in cultivated, reforesting, and natural forest topsoils; rates of C accumulation in reforesting topsoils; and their contribution to the US forest C sink. Our results indicate that reforestation increases topsoil C storage, and that reforesting lands, currently occupying >500,000 km2 in the United States, will sequester a cumulative 1.3–2.1 Pg C within a century (13–21 Tg C·y−1). Annually, these C gains constitute 10% of the US forest sector C sink and offset 1% of all US greenhouse gas emissions.


2020 ◽  
Author(s):  
Mike Beare ◽  
Erin Lawrence-Smith ◽  
Denis Curtin ◽  
Sam McNally ◽  
Frank Kelliher ◽  
...  

<p><span>The global atmospheric concentration of CO<sub>2</sub> and other greenhouse gases (GHG) is steadily increasing. It is estimated that, worldwide, soil C sequestration could offset GHG emissions by 400–1200 Mt C per year. Relative to 1990, New Zealand’s CH<sub>4</sub> and N<sub>2</sub>O emissions in 2013 had increased by 7% and 23% respectively, which translates to an annual emission increase of 1.09 Mt C that could be offset by a similar annual increase in soil C stock. Recent research has shown that some New Zealand pastoral soils are under-saturated in SOC. Subsurface soils (15–30 cm depth) typically have a greater soil C saturation deficit than topsoil (0-30 cm) because plant C inputs (roots) are lower. Using management practices that expose more of the under-saturated soil to higher C inputs could result in increased soil C storage and stabilisation.</span></p><p><span>Pasture renewal (destruction and re-establishment of pasture) is promoted to livestock farmers to improve pasture performance. This typically involves shallow cultivation or direct drilling to establish new grass. Whereas shallow cultivation of soil typically results in a loss of SOC, deeper full inversion tillage (FIT) of soil would result in the burial of C-rich topsoil in closer proximity to mineral material that has a higher stabilisation capacity.  Buried SOC is expected to have a slower decomposition rate owing to less variable temperatures and more anoxic conditions. Deep FIT would also bring under-saturated mineral soil to the surface, where the deposition of SOC from high producing pastures could increase the stabilisation of SOC.  Both the slower turnover of buried SOM and greater stabilisation of new carbon on under-saturated minerals at the soil surface are expected to result in increased SOC sequestration. </span></p><p><span>There is a lack of experimental data to directly address the effect of FIT on soil C stocks in pastoral soils. We applied a simple empirical model to predicting changes in soil C stocks following a one-off application of FIT (30 cm) during pasture renewal. The model accounts for the decomposition of SOC in buried topsoil and the accumulation of C in the new topsoil (inverted subsoil). The model was used to derive national estimates of soil C sequestration under different scenarios of C accumulation efficiency, farmer adoption of FIT and pasture renewal rates.</span></p><p>Our modelled estimates suggest that 32 Mt C could be sequestered over 20 years following a one-time application of FIT (0-30 cm) to 2 M ha of High Producing Grasslands on suitable New Zealand soils. This estimate is based on 100% accumulation efficiency (i.e. topsoil C stocks are returned to pre-inversion levels within 20 years) and a 10% annual rate of pasture renewal. In the absence of direct experimental evidence, a more conservative estimate is warranted, where topsoil C stocks are projected to return to 80% of pre-inversion levels, thus sequestering 20 Mt C. This paper will present our modelled estimates of SOC sequestration during FIT pasture renewal and discuss the potential benefits and adverse effects of deploying this management practice.</p>


Soil Research ◽  
2012 ◽  
Vol 50 (2) ◽  
pp. 83 ◽  
Author(s):  
W. E. Cotching

Soil carbon (C) stocks were calculated for Tasmanian soil orders to 0.3 and 1.0 m depth from existing datasets. Tasmanian soils have C stocks of 49–117 Mg C/ha in the upper 0.3 m, with Ferrosols having the largest soil C stocks. Mean soil C stocks in agricultural soils were significantly lower under intensive cropping than under irrigated pasture. The range in soil C within soil orders indicates that it is critical to determine initial soil C stocks at individual sites and farms for C accounting and trading purposes, because the initial soil C content will determine if current or changed management practices are likely to result in soil C sequestration or emission. The distribution of C within the profile was significantly different between agricultural and forested land, with agricultural soils having two-thirds of their soil C in the upper 0.3 m, compared with half for forested soils. The difference in this proportion between agricultural and forested land was largest in Dermosols (0.72 v. 0.47). The total amount of soil C in a soil to 1.0 m depth may not change with a change in land use, but the distribution can and any change in soil C deeper in the profile might affect how soil C can be managed for sequestration. Tasmanian soil C stocks are significantly greater than those in mainland states of Australia, reflecting the lower mean annual temperature and higher precipitation in Tasmania, which result in less oxidation of soil organic matter.


Geochronology ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 229-245
Author(s):  
Guillaume Guérin ◽  
Christelle Lahaye ◽  
Maryam Heydari ◽  
Martin Autzen ◽  
Jan-Pieter Buylaert ◽  
...  

Abstract. Statistical analysis has become increasingly important in optically stimulated luminescence (OSL) dating since it has become possible to measure signals at the single-grain scale. The accuracy of large chronological datasets can benefit from the inclusion, in chronological modelling, of stratigraphic constraints and shared systematic errors. Recently, a number of Bayesian models have been developed for OSL age calculation; the R package “BayLum” presented herein allows different models of this type to be implemented, particularly for samples in stratigraphic order which share systematic errors. We first show how to introduce stratigraphic constraints in BayLum; then, we focus on the construction, based on measurement uncertainties, of dose covariance matrices to account for systematic errors specific to OSL dating. The nature (systematic versus random) of errors affecting OSL ages is discussed, based – as an example – on the dose rate determination procedure at the IRAMAT-CRP2A laboratory (Bordeaux). The effects of the stratigraphic constraints and dose covariance matrices are illustrated on example datasets. In particular, the benefit of combining the modelling of systematic errors with independent ages, unaffected by these errors, is demonstrated. Finally, we discuss other common ways of estimating dose rates and how they may be taken into account in the covariance matrix by other potential users and laboratories. Test datasets are provided as a Supplement to the reader, together with an R markdown tutorial allowing the reproduction of all calculations and figures presented in this study.


2021 ◽  
Author(s):  
Jussi Heinonsalo ◽  
Anna-Reetta Salonen ◽  
Rashmi Shrestha ◽  
Subin Kalu ◽  
Outi-Maaria Sietiö ◽  
...  

<p>Soil C sequestration through improved agricultural management practices has been suggested to be a cost-efficient tool to mitigate climate change as increased soil C storage removes CO<sub>2</sub> from the atmosphere. In addition, improved soil organic carbon (SOC) content has positive impacts on farming though better soil structure and resilience against climate extremes through e.g. better water holding capacity. In some parts of the world, low SOC content is highly critical problem for overall cultivability of soils because under certain threshold levels of SOC, soil loses its ability to maintain essential ecosystem services for plant production. Soil organic amendments may increase soil C stocks, improve soil structure and boost soil microbial activities with potential benefits in plant growth and soil C sequestration. Additional organic substrates may stimulate microbial diversity that has been connected to higher SOC content and healthy soils.</p><p>We performed a two-year field experiment where the aim was to investigate whether different organic soil amendments have an impact on soil microbial parameters, soil structure and C sequestration.</p><p>The experiment was performed in Parainen in southern Finland on a clay field where oat (Avena sativa) was the cultivated crop. Four different organic soil amendments were used (two wood-based fiber products that were leftover side streams of pulp and paper industry; and two different wood-based biochars). Soil amendments were applied in 2016. Soil C/N analysis was performed in the autumns 2016-2018 and soil aggregate in the summer and autumn 2018, as well as measures to estimate soil microbial activity: microbial biomass, soil respiration, enzymatic assays, microbial community analysis with Biolog ®  EcoPlates and litter bag decomposition experiment. The relative share of bacteria and fungi was determined using qPCR from soil samples taken in the autumns 2016, 2017 and 2018.</p><p>Data on how the studied organic soil amendments influence soil structure and C content, as well as soil microbial parameters will be presented and discussed.</p>


2021 ◽  
Author(s):  
Rose Abramoff ◽  
Bertrand Guenet ◽  
Haicheng Zhang ◽  
Katerina Georgiou ◽  
Xiaofeng Xu ◽  
...  

<p>Soil carbon (C) models are used to predict C sequestration responses to climate and land use change. Yet, the soil models embedded in Earth system models typically do not represent processes that reflect our current understanding of soil C cycling, such as microbial decomposition, mineral association, and aggregation. Rather, they rely on conceptual pools with turnover times that are fit to bulk C stocks and/or fluxes. As measurements of soil fractions become increasingly available, soil C models that represent these measurable quantities can be evaluated more accurately. Here we present Version 2 (V2) of the Millennial model, a soil model developed to simulate C pools that can be measured by extraction or fractionation, including particulate organic C, mineral-associated organic C, aggregate C, microbial biomass, and dissolved organic C. Model processes have been updated to reflect the current understanding of mineral-association, temperature sensitivity and reaction kinetics, and different model structures were tested within an open-source framework. We evaluated the ability of Millennial V2 to simulate total soil organic C (SOC), as well as the mineral-associated and particulate fractions, using three soil fractionation data sets spanning a range of climate and geochemistry in Australia (N=495), Europe (N=176), and across the globe (N=730). Millennial V2 (RMSE = 1.98 – 4.76 kg, AIC = 597 – 1755) generally predicts SOC content better than the widely-used Century model (RMSE = 2.23 – 4.8 kg, AIC = 584 – 2271), despite an increase in process complexity and number of parameters. Millennial V2 reproduces between-site variation in SOC across a gradient of plant productivity, and predicts SOC turnover times similar to those of a global meta-analysis. Millennial V2 updates the conceptual Century model pools and processes and represents our current understanding of the roles that microbial activity, mineral association and aggregation play in soil C sequestration.</p>


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Lefebvre ◽  
Adrian Williams ◽  
Jeroen Meersmans ◽  
Guy J. D. Kirk ◽  
Saran Sohi ◽  
...  

Abstract Sugarcane (Saccharum officinarum L.) cultivation leaves behind around 20 t ha−1 of biomass residue after harvest and processing. We investigated the potential for sequestering carbon (C) in soil with these residues by partially converting them into biochar (recalcitrant carbon-rich material). First, we modified the RothC model to allow changes in soil C arising from additions of sugarcane-derived biochar. Second, we evaluated the modified model against published field data, and found satisfactory agreement between observed and predicted soil C accumulation. Third, we used the model to explore the potential for soil C sequestration with sugarcane biochar in São Paulo State, Brazil. The results show a potential increase in soil C stocks by 2.35 ± 0.4 t C ha−1 year−1 in sugarcane fields across the State at application rates of 4.2 t biochar ha−1 year−1. Scaling to the total sugarcane area of the State, this would be 50 Mt of CO2 equivalent year−1, which is 31% of the CO2 equivalent emissions attributed to the State in 2016. Future research should (a) further validate the model with field experiments; (b) make a full life cycle assessment of the potential for greenhouse gas mitigation, including additional effects of biochar applications on greenhouse gas balances.


2015 ◽  
Vol 12 (5) ◽  
pp. 1615-1627 ◽  
Author(s):  
J. D. M. Speed ◽  
V. Martinsen ◽  
A. J. Hester ◽  
Ø. Holand ◽  
J. Mulder ◽  
...  

Abstract. Treelines differentiate vastly contrasting ecosystems: open tundra from closed forest. Treeline advance has implications for the climate system due to the impact of the transition from tundra to forest ecosystem on carbon (C) storage and albedo. Treeline advance has been seen to increase above-ground C stocks as low vegetation is replaced with trees but decrease organic soil C stocks as old carbon is decomposed. However, studies comparing across the treeline typically do not account for elevational variation within the ecotone. Here we sample ecosystem C stocks along an elevational gradient (970 to 1300 m), incorporating a large-scale and long-term livestock grazing experiment, in the southern Norwegian mountains. We investigate whether there are continuous or discontinuous changes in C storage across the treeline ecotone, and whether these are modulated by grazing. We find that vegetation C stock decreases with elevation, with a clear breakpoint between the forest line and treeline above which the vegetation C stock is constant. C stocks in organic surface horizons of the soil were higher above the treeline than in the forest, whereas C stocks in mineral soil horizons are unrelated to elevation. Total ecosystem C stocks also showed a discontinuous elevational pattern, increasing with elevation above the treeline (8 g m−2 per metre increase in elevation), but decreasing with elevation below the forest line (−15 g m−2 per metre increase in elevation), such that ecosystem C storage reaches a minimum between the forest line and treeline. We did not find any effect of short-term (12 years) grazing on the elevational patterns. Our findings demonstrate that patterns of C storage across the treeline are complex, and should be taken account of when estimating ecosystem C storage with shifting treelines.


2007 ◽  
Vol 87 (1) ◽  
pp. 93-102 ◽  
Author(s):  
J M Kranabetter ◽  
A M Macadam

The extent of carbon (C) storage in forests and the change in C stocks after harvesting are important considerations in the management of greenhouse gases. We measured changes in C storage over time (from postharvest, postburn, year 5, year 10 and year 20) in logging slash, forest floors, mineral soils and planted lodgepole pine (Pinus contorta var. latifolia) trees from six prescribed-burn plantations in north central British Columbia. After harvest, site C in these pools averaged 139 Mg ha-1, with approximately equal contributions from mineral soils (0–30 cm), forest floors and logging slash. Together these detrital pools declined by 71 Mg C ha-1, or 51% (28% directly from the broadcast burn, and a further 23% postburn), in the subsequent 20 yr. Postburn decay in logging slash was inferred by reductions in wood density (from 0.40 to 0.34 g cm-3), equal to an average k rate of 0.011 yr-1. Losses in forest floor C, amounting to more than 60% of the initial mass, were immediate and continued to year 5, with no reaccumulation evident by year 20. Mineral soil C concentrations initially fluctuated before declining by 25% through years 10 and 20. Overall, the reductions in C storage were offset by biomass accumulation of lodgepole pine, and we estimate these plantations had become a net sink for C before year 20, although total C storage was still less than postharvest levels. Key words: C sequestration, forest floors; coarse woody debris; soil organic matter


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