Soil Carbon Stocks Research Articles

Root-derived carbon stocks in formerly deep-ploughed soils – A biomarker-based approach

Roots can add significant amounts of carbon (C) to the subsoil, which improves soil physical properties and can mitigate climate change. About 5% of croplands in Germany have been deep-ploughed (30–120 cm) at least once. This can provide better root access to the subsoil and may increase yields, but little is known on the fate of root-derived C in the subsoil (at depth greater than 30 cm) after deep-ploughing. We hypothesized that five decades after deep-ploughing, root-derived C stocks were higher than conventionally ploughed treatments due to better root development. We analysed suberin and cutin monomers as tracers for root- and shoot-derived C at three former deep-ploughed sites in Northern Germany with different soil textures and deep-ploughing depths. Concentrations of suberin monomers in the soil positively correlated with root biomass; this was most pronounced at one sandy site, but had higher variability at the other two sites due to crops with different root systems in the crop rotation, lower root development, and more favourable conditions for C decomposition. Suberin contributed more to the bulk soil organic carbon (SOC) stocks than cutin throughout the soil profile at all sites. The contribution of suberin monomers to the bulk SOC stock at silty site Banteln and the sandy site Essemühle was 38% higher in the deep-ploughed plots than at the reference plot, respectively, these differences were most visible in the subsoil of Essemühle. We conclude that as C stocks and root development increase, suberin SOC stocks also increase, especially in sandy subsoils with low pH.

The hidden risk: Changes in functional potentials of microbial keystone taxa under global climate change jeopardizing soil carbon storage in alpine grasslands

Climate change is endangering the soil carbon stock of alpine grasslands on the Qinghai-Tibetan Plateau (QTP), but the limited comprehension regarding the mechanisms that sustain carbon storage under hydrothermal changes increases the uncertainty associated with this finding. Here, we examined the relative abundance of soil microbial keystone taxa and their functional potentials, as well as their influence on soil carbon storage with increased precipitation across alpine grasslands on the QTP, China. The findings indicate that alterations in precipitation significantly decreased the relative abundance of the carbon degradation potentials of keystone taxa, such as chemoheterotrophs. The inclusion of keystone taxa and their internal functional potentials in the two best alternative models explained 70% and 63% of the variance in soil organic carbon (SOC) density, respectively. Moreover, we found that changes in chemoheterotrophs had negative effects on SOC density as indicated by a structural equation model, suggesting that some specialized functional potentials of keystone taxa are not conducive to the accumulation of carbon sink. Our study offers valuable insights into the intricate correlation between precipitation-induced alterations in soil microbial keystone taxa and SOC storage, highlighting a rough categorization is difficult to distinguish the hidden threats and the importance of incorporating functional potentials in SOC storage prediction models in response to changing climate.

Human population density and blue carbon stocks in mangroves soils

Mangrove soils provide many important ecosystem services such as carbon sequestration, yet they are vulnerable to the negative impacts brought on by anthropogenic activities. Research in recent decades has shown a progressive loss of blue carbon in mangrove forests as they are converted to aquaculture, agriculture, and urban development. We seek to study the relationship between human population density and soil carbon stocks in urban mangrove forests to quantify their role in the global carbon budget. To this end, we conducted a global analysis, collecting mangrove soil carbon data from previous studies and calculating population density for each study location utilizing a recent database from the European Commission. Results indicate population density has a negative association with mangrove soil carbon stocks. When human population density reaches 300 people km−2, which is defined as ‘urban domains’ in the European Commission database, mangrove soil carbon is estimated to be lower than isolated mangrove forests by 37%. Nonetheless, after accounting for climatic factors in the model, we see the negative relationship between population density and soil carbon is reduced and is even non-significant in mixed effects models. This suggests population density is not a good measure for the direct effects of humans on mangrove ecosystems and further implies mangrove ecosystems in close proximity to very high population density can still possess valuable carbon stocks. Our work provides a better understanding of how soil carbon stocks in existing mangrove forests correlate with different levels of population density, underscores the importance of protecting existing mangroves and especially those in areas with high human population density, and calls for further studies on the association between human activities and mangrove forest carbon stocks.

Carbon and nitrogen stock in soils of subtropical urban forests: Isotopic δ13C and δ15N indicators for nature-based solutions in a megacity

Urban forest soils play a pivotal role in enhancing the environmental sustainability of cities, contributing to various natural processes, including plant–microbe interactions, microbial activity, and the decomposition of organic matter. Consequently, urban forest soils emerge as effective NBS, underscoring their potential to mitigate environmental challenges and foster sustainable urban ecosystems. In these sense, this manuscript aimed at evaluating how soil attributes of the urban forests of São Paulo, Brazil, with different adjacent land uses, influence the capacity to store the excess of C and N from anthropogenic emissions, making this ecosystem an important reservoir of urban anthropogenic emissions. Three hundred urban forest soil samples were collected from the surface to a depth of 50 cm. All samples were analyzed for C and N content (and their stable isotopes). In addition, granulometric tests were also carried out to classify the soils. It was found that the most central forest fragment has the highest C and N contents at all analyzed depths, probably due to the association with physical aspects of soil texture. For all layers, the most central fragment soil sample, the only one with a clay soil, presented approximately twice as many elements when compared to the soil samples of the other sites. In general, C and N stocks (and their stable isotopes, δ13C and δ15N, respectively) varied significantly in forests located in the center-periphery direction (%N - F = 24.58, p < 0.05; %C - F = 22.48, p < 0.05; δ15N - F = 4.27, p < 0.05; δ13C - F = 19.8, p < 0.05; C/N - F = 14.56, p < 0.05). This more central forest fragment with higher vehicle emissions showed greater potential to store these atmospheric elements and with greater neutralizing efficiency than the other forest fragments. δ13C and δ15N contents together with the C:N ratio indicated the efficiency of biogeochemical cycling, through decomposition, in different urban forest fragments. More peripheral fragments showed high efficiency in C and N cycling along the analyzed soil profiles, while in the most superficial layer, the most central fragment was highly efficient. These shed light results how integrating NbS principles into strategic urban planning and city-level climate policies can bolster the effectiveness of urban green areas. The integration not only promotes carbon sequestration and efficient nutrient cycling in the soil but also fosters sustainable practices, contributing to a more resilient urban landscape.

Emergent temperature sensitivity of soil organic carbon driven by mineral associations

Soil organic matter decomposition and its interactions with climate depend on whether the organic matter is associated with soil minerals. However, data limitations have hindered global-scale analyses of mineral-associated and particulate soil organic carbon pools and their benchmarking in Earth system models used to estimate carbon cycle–climate feedbacks. Here we analyse observationally derived global estimates of soil carbon pools to quantify their relative proportions and compute their climatological temperature sensitivities as the decline in carbon with increasing temperature. We find that the climatological temperature sensitivity of particulate carbon is on average 28% higher than that of mineral-associated carbon, and up to 53% higher in cool climates. Moreover, the distribution of carbon between these underlying soil carbon pools drives the emergent climatological temperature sensitivity of bulk soil carbon stocks. However, global models vary widely in their predictions of soil carbon pool distributions. We show that the global proportion of model pools that are conceptually similar to mineral-protected carbon ranges from 16 to 85% across Earth system models from the Coupled Model Intercomparison Project Phase 6 and offline land models, with implications for bulk soil carbon ages and ecosystem responsiveness. To improve projections of carbon cycle–climate feedbacks, it is imperative to assess underlying soil carbon pools to accurately predict the distribution and vulnerability of soil carbon.

Effects of Agricultural Expansion on Soil Carbon and Nitrogen Stocks in the Amazon Deforestation Arc

Typical successions in land use affect the dynamics of carbon (C) and nitrogen (N) in the soil. This study aimed to determine the effects of land use change on soil organic carbon and N content and stocks in pastures, crops, and forests in the Amazon. Soil C and N stocks were assessed at depths of 30 and 100 cm to determine 13C isotopic abundance. The concentrations of C and N in crops were lower (p &lt; 0.05) than those in other land use types. Soil organic C and soil N stocks for pasture (67.6, 144.8, 5.7, and 13.3) and forest (77.1, 137.5, 6.3, and 13.8) systems were similar, but greater than those of the crop area (36.4, 63.9, 3.0, and 6.0), regardless of depth (30 and 100 cm for C and N). Land use change for pastures in the Arc of Deforestation region of the Amazon maintains SOC and N stocks in the soil and is more sustainable than the agricultural system with black pepper, as long as the conditions of soil, climate, and cultivation are similar. Part of the C3-derived carbon from the forest was replaced by C4-derived C from grasses at soil depths up to 100 cm.

Age of Soil and Water Conservation Practices on Selected Soil Properties along the Toposequence of Gerado Watershed, Habru District, Eastern Amhara, Ethiopia

The government of Ethiopia through community participation has widely implemented soil and water conservation (SWC) measures, especially in the highlands of Ethiopia. However, the effects of these practices on the physicochemical properties of soils have not been well assessed and documented in the study area. Thus, this experiment was conducted to evaluate the effects of SWC practice on selected soil physicochemical properties. Treatments were nonconserved land, 3- and 9-year-old soil conservation practices under three slope positions, namely, lower slope (0–8%), middle slope (9–15%), and upper slope (&gt;15%) positions, and at two soil depths (0–20 and 20–40 cm) with three replications. Accordingly, 54 composite soil samples were collected and analyzed based on standard procedures. The results showed that the age of soil and water conservation practice, topography, and soil depths significantly affected most of the soil properties. Conserving the watershed for nine years improved the subsoil clay content from 37.1 to 46.3%, subsoil soil moisture content from 13.38 to 24.61%, surface total nitrogen content from 18.1 to 81%, available phosphorus content from 13.1 to 33.5 mg kg−1, surface organic carbon from 0.28 to 2.83%, soil carbon stock from 9.26 to 35.59 t ha−1, and surface cation exchange capacity from 21.5 to 57.4 Cmolec kg−1. Therefore, maintaining soil and water conservation practices for long periods can improve soil properties. However, planting different grasses, with the existing physical structures is needed to increase soil nutrient and carbon stock.

Evaluation and optimisation of the soil carbon turnover routine in the MONICA model (version 3.3.1)

Abstract. Simulation models are tools commonly used to predict changes in soil carbon stocks. Prior validation is essential, however, for determining the reliability and applicability of model results. In this study, the process-based biogeochemical model MONICA (Model of Nitrogen and Carbon dynamics on Agro-ecosystems) was evaluated with respect to soil organic carbon (SOC), using long-term monitoring data from 46 German agricultural sites. A revision and parameterisation of equations, encompassing crop- and fertiliser-specific C contents and the abiotic factors of soil temperature, soil water and clay content, were undertaken and included in the model. The modified version was also used for a Morris elementary effects screening method, which confirmed the importance of environmental and management factors to the model's performance. The model was then calibrated by means of Bayesian inference, using the Metropolis–Hastings algorithm. The performance of the MONICA model was compared with that of five established carbon turnover models (CCB, CENTURY, C-TOOL, ICBM and RothC). The original MONICA model systematically overestimated SOC decomposition rates and produced on average a ∼17 % greater mean absolute error (MAE) than the other models. The modification and calibration significantly improved its performance, reducing the MAE by ∼30 %. Consequently, MONICA outperformed CENTURY, CCB and C-TOOL, and produced results comparable with ICBM and RothC. Use of the modified model allowed mostly adequate reproduction of site-specific SOC stocks, while the availability of a nitrogen, plant growth and water submodel enhanced its applicability when compared with models that only describe carbon dynamics.

Rainforest transformation reallocates energy from green to brown food webs

Terrestrial animal biodiversity is increasingly being lost because of land-use change1,2. However, functional and energetic consequences aboveground and belowground and across trophic levels in megadiverse tropical ecosystems remain largely unknown. To fill this gap, we assessed changes in energy fluxes across ‘green’ aboveground (canopy arthropods and birds) and ‘brown’ belowground (soil arthropods and earthworms) animal food webs in tropical rainforests and plantations in Sumatra, Indonesia. Our results showed that most of the energy in rainforests is channelled to the belowground animal food web. Oil palm and rubber plantations had similar or, in the case of rubber agroforest, higher total animal energy fluxes compared to rainforest but the key energetic nodes were distinctly different: in rainforest more than 90% of the total animal energy flux was channelled by arthropods in soil and canopy, whereas in plantations more than 50% of the energy was allocated to annelids (earthworms). Land-use change led to a consistent decline in multitrophic energy flux aboveground, whereas belowground food webs responded with reduced energy flux to higher trophic levels, down to −90%, and with shifts from slow (fungal) to fast (bacterial) energy channels and from faeces production towards consumption of soil organic matter. This coincides with previously reported soil carbon stock depletion3. Here we show that well-documented animal biodiversity declines with tropical land-use change4–6 are associated with vast energetic and functional restructuring in food webs across aboveground and belowground ecosystem compartments.

SOIL CARBON STOCKS NOT LINKED TO ABOVEGROUND LITTER INPUT AND CHEMISTRY OF OLD-GROWTH FOREST AND ADJACENT PRAIRIE

ABSTRACT The long-standing assumption that aboveground plant litter inputs have a substantial influence on soil organic carbon storage (SOC) and dynamics has been challenged by a new paradigm for SOC formation and persistence. We tested the importance of plant litter chemistry on SOC storage, distribution, composition, and age by comparing two highly contrasting ecosystems: an old-growth coast redwood (Sequoia sempervirens) forest, with highly aromatic litter, and an adjacent coastal prairie, with more easily decomposed litter. We hypothesized that if plant litter chemistry was the primary driver, redwood would store more and older SOC that was less microbially processed than prairie. Total soil carbon stocks to 110 cm depth were higher in prairie (35 kg C m−2) than redwood (28 kg C m−2). Radiocarbon values indicated shorter SOC residence times in redwood than prairie throughout the profile. Higher amounts of pyrogenic carbon and a higher degree of microbial processing of SOC appear to be instrumental for soil carbon storage and persistence in prairie, while differences in fine-root carbon inputs likely contribute to younger SOC in redwood. We conclude that at these sites fire residues, root inputs, and soil properties influence soil carbon dynamics to a greater degree than the properties of aboveground litter.

A random forest model to predict soil organic carbon storage in mangroves from Southern Colombian Pacific coast

Mangrove ecosystems serve as significant reservoirs of carbon stocks, particularly within the soil. However, these ecosystems face widespread degradation globally, underscoring the necessity for comprehensive technical insights to facilitate effective management. Enhancing the precision of soil organic carbon estimates within mangroves necessitates access to precise field data. Hence, this study aimed to assess the soil organic carbon stored in mangrove ecosystems along the southern Colombian Pacific coast. Employing a Random Forest model, constructed with data from 28 soil profiles spanning a depth of 2 m and 16 predictor variables, we evaluated the model's performance using repeated 10-fold cross-validation (with 5 random repeats). Uncertainty in carbon storage predictions was quantified through 95% confidence intervals. Our model successfully accounted for 88% of the variability in soil organic carbon storage. Depth, cation exchange capacity, pH, and sand content emerged as the most influential predictors of soil organic carbon storage variation. The study estimated a mean of 270.32 ± 52.75 t C ha−1, with a total carbon reserve of 25458088 t in the study area. Notably, this value falls below global estimates, suggesting a potential overestimation of carbon stocks in mangrove soils by existing global models.

Carbon and nitrogen stocks in Lithic soils: Environmental drivers and land-use implication in Brazilian dry ecosystems

Carbon and nitrogen stocks in Lithic soils: Environmental drivers and land-use implication in Brazilian dry ecosystems

Enhancement effects of mangrove restoration on blue carbon storage in Qinzhou Bay

IntroductionMangroves are the main carbon sinks in tropical regions and have high capabilities for carbon sequestration. Protection and restoration of mangroves are necessary to reduce carbon emissions and fight climate change. While the Qinzhou Bay as the main area of national mangrove restoration plan in the future, studies on its carbon pools, especially assessment of the carbon sink enhancement effect of restored mangroves along forest chronosequence, are lacking.MethodsThis study aimed to quantify the changes in restored mangrove soil carbon stock, vegetation and root carbon stocks along the forest age sequence in Qinzhou Bay through field survey.ResultsThe results revealed that the carbon stocks of vegetation and roots significantly increased with the developing forest age. Only in the soil layer above 30 cm, the soil carbon storage apparently increased with the developing forest age in non-cofferdam area, and then decreased slowly after reaching the peak (at 6 ~ 8 years). Moreover, the soil carbon storage of mangroves was greater in the cofferdam area than in the non-cofferdam area.DiscussionThis implied that the cofferdam restoration efforts may be more effective in enhancing blue carbon storage, during the initial stages of the restoration process. The results of this study suggested that mangrove restoration has substantial potential capacity in carbon storage and nutrient cycling, providing a reference for the protection and restoration efforts concerning mangroves.

Land use change and forest management effects on soil carbon stocks in the Northeast U.S.

BackgroundIn most regions and ecosystems, soils are the largest terrestrial carbon pool. Their potential vulnerability to climate and land use change, management, and other drivers, along with soils’ ability to mitigate climate change through carbon sequestration, makes them important to carbon balance and management. To date, most studies of soil carbon management have been based at either large or site-specific scales, resulting in either broad generalizations or narrow conclusions, respectively. Advancing the science and practice of soil carbon management requires scientific progress at intermediate scales. Here, we conducted the fifth in a series of ecoregional assessments of the effects of land use change and forest management on soil carbon stocks, this time addressing the Northeast U.S. We used synthesis approaches including (1) meta-analysis of published literature, (2) soil survey and (3) national forest inventory databases to examine overall effects and underlying drivers of deforestation, reforestation, and forest harvesting on soil carbon stocks. The three complementary data sources allowed us to quantify direction, magnitude, and uncertainty in trends.ResultsOur meta-analysis findings revealed regionally consistent declines in soil carbon stocks due to deforestation, whether for agriculture or urban development. Conversely, reforestation led to significant increases in soil C stocks, with variation based on specific geographic factors. Forest harvesting showed no significant effect on soil carbon stocks, regardless of place-based or practice-specific factors. Observational soil survey and national forest inventory data generally supported meta-analytic harvest trends, and provided broader context by revealing the factors that act as baseline controls on soil carbon stocks in this ecoregion of carbon-dense soils. These factors include a range of soil physical, parent material, and topographic controls, with land use and climate factors also playing a role.ConclusionsForest harvesting has limited potential to alter forest soil C stocks in either direction, in contrast to the significant changes driven by land use shifts. These findings underscore the importance of understanding soil C changes at intermediate scales, and the need for an all-lands approach to managing soil carbon for climate change mitigation in the Northeast U.S.

SAMM version 1.0: a numerical model for microbial- mediated soil aggregate formation

Abstract. Maintaining soil organic matter (SOM) is crucial for healthy and productive agricultural soils and requires understanding at the process level, including the role of SOM protection by soil aggregates and the connection between microbial growth and aggregate formation. We developed the Soil Aggregation through Microbial Mediation (SAMM) model, to represent this important connection. The pools of SAMM are fully measurable, and we calibrated and evaluated it against data from a long-term bare fallow experiment in a tropical sandy soil. This experiment received additions of plant litter of different compositions, which resulted in twice the soil carbon stocks in the best treatment compared to the control (about 8 vs. 4 t C ha−1 in 0–15 cm soil depth) after 25 years. As hypothesized, the SAMM model effectively represented the microbial growth response after the addition of litter and the subsequent formation and later destabilization of aggregates. The low correlations between different calibrated model parameters (r&lt;0.5 for all parameters; r&gt;0.4 for only 4 of 22) showed that SAMM is parsimonious. SAMM was able to capture differences between treatments in soil organic carbon (Nash–Sutcliffe modeling efficiency (EF) of 0.68), microbial nitrogen (EF of 0.24), and litter carbon (EF of 0.80). The amount of carbon within the aggregates (EF of 0.60) and in the free silt and clay fraction (EF of 0.24) was also simulated very well to satisfactorily. Our model results suggested that in spite of the sandy soil, up to 50 % of carbon stocks were stabilized through aggregate protection mechanisms; and that microbial and physical aggregate formation coexists. A version of the SAMM model without aggregate protection (SAMMnoAgg) initially failed to stabilize soil organic carbon (EF decreased to −3.68) and the simulation of microbial nitrogen worsened (EF of 0.13). By recalibrating SAMMnoAgg, it was possible to partially correct for the lack of aggregate protection by reducing the rate of mineral-attached carbon decomposition by about 85 % (EF of 0.68, 0.75, and 0.18 for SOC, litter carbon, and microbial nitrogen, respectively). However, the slightly better evaluation statistics of SAMM (e.g., Akaike information criterion of 5351 vs. 5554) suggest that representing aggregate dynamics in SOM models can be beneficial and necessary to understand the mechanism behind SOM dynamics. Our results indicate that current models without aggregate formation partly compensate for the absence of aggregate protection by lowering the turnover rates of other pools. Thus, they remain suitable options where data on aggregate associated carbon are not available.

High-resolution mapping of soil carbon stocks in the western Amazon

Global soil carbon maps are essential to understanding the global carbon cycle and supporting policy decisions, but their uncertainty in remote areas with limited data remains a significant challenge. Assessing and quantifying soil carbon at a regional level can shed light on existing uncertainties in global maps, providing more dependable information for stakeholders. Therefore, we aimed to model and map the soil organic carbon (SOC) stock in the Western Amazon, state of Rondônia, which witnessed a loss of 30% of its native coverage in the last 35 years. We used information from almost three thousand soil profiles that have not been included in the modeling of global and national existing soil maps. SOC stocks were stratified at 0–5, 5–15, 15–30, 30–60, and 60–100 cm depths and we selected the environmental predictors based on correlation < |0.95| and importance (recursive feature elimination). To reduce uncertainties and select the best model, we tested six different machine learning algorithms and ran the models 100 times for each depth with different subsets of samples, resulting in maps of mean, quantiles (Q05 and Q95), and uncertainty (Coefficient of variation). The Random Forest model presented the best performance, and the soil class was one of the predictors that most influenced the SOC stock, especially in the superficial layers (0–30 cm). The largest SOC stocks are in the southern region (protected areas), at low altitudes and places with seasonal flooding dynamics, and the smallest values are found in the central region, associated with the high-weathered Latossolos. Our results show that national and global maps overestimate SOC stocks (up +100 Mg C ha−1) in the central region with lower SOC stocks, and underestimate (− 400 Mg C ha−1) in the southern region with higher SOC stocks. These higher SOC stocks are concentrated in protected areas, but this information was hidden until now since global and national SOC maps could not identify these hotspots. Although global and national maps are handy for first assessment in locations without specific information, regional soil sampling and mapping should be used in hotspots of soil carbon sequestration and land use changes to ensure the continuous protection of these areas.

Carbon and Nitrogen Stocks in Agricultural Soils under Different Natural Conditions and Management in Slovakia

Soil is a natural capital which supplies valuable ecosystem services including carbon and nitrogen storage. Agroecosystems play an important role in soil organic carbon (SOC) and soil total nitrogen (NT) accumulation. The aim of this study was to analyse SOC stock (SOCS) and NT stock (NTS) in relation to land use (arable land-AL, permanent grasslands-PG), management, soil depth, and selected soil properties of six soil subtypes (Rendzic Leptosol—LPrz, Dystric Cambisol—CMdy, Stagnic Cambisol—CMst, Haplic Fluvisol—FLha, Gleyic Fluvisol—FLgl, Haplic Chernozem—CHha) which are the most widespread in Slovakia. SOCS for a 50 cm deep soil profile ranged from 161 t.ha−1 in CHha to 59 t.ha−1 in FLgl in grasslands, and in arable lands from 111 t.ha−1 in CHha to 38 t.ha−1 in CMst. In grasslands, FLs and CMst showed the significantly lowest SOCS and NTS in comparison to CMdy, LPrz, and CHha. The mean soil NT content in arable land and grasslands was 2.21 g.kg−1 and 2.82 g.kg−1, respectively. ANOVA showed that soil subtype, land use, and site have significantly affected SOCS but not NTS. The correlation analysis revealed correlations between SOCS and NTS. SOCS was also correlated with C:N, pH, P, and K. This study should help to encourage practices to maintain soil C and soil properties and to ensure the sustainability of the functions of many soil types in Slovakia.

Understanding carbon storage dynamics in Ayeyarwady delta's mangrove ecosystem in Myanmar: insights for restoration efforts

Mangroves are highly valued for their ecosystem services, providing a wide range of ecological, social, and economic benefits, including their role as carbon-rich ecosystems. Recent research suggests that preserving mangrove forests can offer a cost-effective strategy for mitigating CO2 emissions. However, extensive deforestation has placed mangrove ecosystems under severe global threats. Currently, the assessment of mangrove restoration outcomes, particularly regarding soil carbon stocks, is inadequate. Therefore, this study aims to investigate the impact of restoration on soil organic carbon (SOC) in Shwe Thaung Yan, Ayeyarwady coastal region of Myanmar. The study aimed to quantify and compare carbon stocks in different soil layers, examine the carbon sequestration potential of various mangrove species, and evaluate the effectiveness of mangrove restoration efforts. Soil samples were collected in 2015 (pre-restoration) and 2021 (post-restoration) at various soil depths and analyzed for SOC concentration, organic matter content, and bulk density using the Loss on Ignition (LOI) procedure. Significant changes in soil properties were observed between 2015 and 2021, with higher SOC and carbon concentrations observed in 2021. The average soil carbon stocks in 2021 (1954.43 ± 33.24 Mg C ha−1) were approximately 2.7 times higher than the estimated carbon stocks in 2015 (732.26 ± 6.99 Mg C ha−1). Furthermore, the study revealed variations in SOC accumulation among different soil depths, with higher carbon stocks found in the upper soil layers. This study highlights the positive impact of mangrove restoration on SOC accumulation and emphasizes the significance of considering soil carbon dynamics in restoration initiatives. The findings offer valuable insights for the conservation and management of mangrove ecosystems, especially concerning their potential for carbon sequestration and their contribution to mitigating climate change.

Effect of Forest Reclamation on Carbon Stocks and Respiration of Soils of Natural and Technogenic Ecosystems of Southern Karelia

Effect of Forest Reclamation on Carbon Stocks and Respiration of Soils of Natural and Technogenic Ecosystems of Southern Karelia

Switchgrass (Panicum virgatum L.) cultivars have similar impacts on soil carbon and nitrogen stocks and microbial function

AbstractSwitchgrass (Panicum virgatum L.) production for biofuel has the potential to produce reasonable yields on lands not suited for conventional agriculture. We assessed nine switchgrass cultivars representing lowland and upland ecotypes grown for 11 years at a site in the upper Midwest USA for belowground differences in soil carbon and nitrogen stocks, soil organic matter fractions, and standing root biomass to 1 m depth. We also compared potential nitrogen mineralization and carbon substrate use through community‐level physiological profiling in surface soils (0–10 cm depth). Average yields and standing root biomass differed among cultivars and between ecotypes, but we found no significant cultivar‐related impacts on soil carbon and nitrogen stocks, on the distribution of particulate and mineral‐associated soil organic matter fractions, nor on potential nitrogen mineralization or microbial community‐level physiological profiles. That these traits did not differ among cultivars suggests that soil carbon and nitrogen gains under switchgrass are likely to be robust with respect to cultivar differences, and to this point not much affected by breeding efforts.