Conversion of marginal land into switchgrass conditionally accrues soil carbon and reduces methane consumption

AbstractSwitchgrass (Panicum virgatum L.) is a perennial C4 grass native to tallgrass prairies of the Central US, and a promising bioenergy feedstock. Switchgrass can be cultivated on soils with low nutrient contents and its rooting depth, of up to 2 m, has brought attention to the crop as a potential mechanism to sequester and build soil carbon (C). Switchgrass, therefore, offers multifaceted benefits on degraded soils by enhancing soil organic matter content. However, to evaluate the sustainability of switchgrass-based biofuel production, it is crucial to understand the impacts of land conversion and switchgrass establishment on biotic/abiotic characteristics of various soils. In this study, we characterized the ecosystem-scale consequences of switchgrass growing at two highly-eroded, ‘Dust Bowl’ remnant field sites from Oklahoma US, with silt-loam (SL) or clay-loam (CL) soil textures having low nitrogen (N), phosphorus (P), and C contents. Paired plots at each site, including fallow control and switchgrass-cultivated, were assessed. Our results indicated that switchgrass significantly increased soil C at the SL site and reduced microbial diversity at the CL site. The CL site exhibited significantly higher CO2 flux and higher respiration from switchgrass plots. Strikingly, switchgrass significantly reduced the CH4 consumption by an estimated 39% for the SL site and 47% for the CL site. Structural equation modeling identified soil temperature, P content, and soil moisture levels as the most influential factors regulating both CO2 and CH4 fluxes. CO2 flux was also influenced by microbial biomass while CH4 flux was influenced by microbial diversity. Together, our results suggest that site selection by soil type is a crucial factor in improving soil C stocks and mitigating greenhouse gas (GHG) fluxes, especially considering our finding that switchgrass reduced methane consumption, implying that carbon balance considerations should be accounted for to fully evaluate the sustainability of switchgrass cultivation.

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Soil microbial diversity–biomass relationships are driven by soil carbon content across global biomes

The ISME Journal ◽

10.1038/s41396-021-00906-0 ◽

2021 ◽

Author(s):

Felipe Bastida ◽

David J. Eldridge ◽

Carlos García ◽

G. Kenny Png ◽

Richard D. Bardgett ◽

...

Keyword(s):

Microbial Diversity ◽

Soil Carbon ◽

Soil Microbial Communities ◽

Ecosystem Functions ◽

Arid Environments ◽

Soil Microbial Diversity ◽

Soil Biodiversity ◽

Soil C ◽

Soil Microbial ◽

Biomass Ratio

AbstractThe relationship between biodiversity and biomass has been a long standing debate in ecology. Soil biodiversity and biomass are essential drivers of ecosystem functions. However, unlike plant communities, little is known about how the diversity and biomass of soil microbial communities are interlinked across globally distributed biomes, and how variations in this relationship influence ecosystem function. To fill this knowledge gap, we conducted a field survey across global biomes, with contrasting vegetation and climate types. We show that soil carbon (C) content is associated to the microbial diversity–biomass relationship and ratio in soils across global biomes. This ratio provides an integrative index to identify those locations on Earth wherein diversity is much higher compared with biomass and vice versa. The soil microbial diversity-to-biomass ratio peaks in arid environments with low C content, and is very low in C-rich cold environments. Our study further advances that the reductions in soil C content associated with land use intensification and climate change could cause dramatic shifts in the microbial diversity-biomass ratio, with potential consequences for broad soil processes.

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Changes in soil carbon and soil nitrogen after tree clearing in the semi-arid rangelands of Queensland

Australian Journal of Botany ◽

10.1071/bt04154 ◽

2005 ◽

Vol 53 (7) ◽

pp. 639 ◽

Cited By ~ 29

Author(s):

B. P. Harms ◽

R. C. Dalal ◽

A. P. Cramp

Keyword(s):

Soil Carbon ◽

Soil Depth ◽

Woody Debris ◽

Soil Phosphorus ◽

Basal Area ◽

Clay Content ◽

Strongly Correlated ◽

Soil N ◽

Soil C ◽

C Stocks

Changes in soil carbon (C) and nitrogen (N) stocks following tree clearing were estimated at 32 rangeland sites in central and southern Queensland by using paired-site sampling. When corrected for soil bulk-density differences at each site, average soil C across all sites decreased after tree clearing by 8.0% for 0–0.3-m soil depth, and by 5.4% for 0–1.0-m depth; there were corresponding declines in soil C of 2.5 and 3.5tha–1, respectively. Mean soil C stocks (excluding surface litter, extractable roots and coarse charcoal) at uncleared sites were 29.5tha–1 for 0–0.3-m soil depth, and 62.5tha–1 for 0–1.0-m depth. Mean soil C stocks (0–0.3m) were 41% of the mean total C for the soil–plant system (soil + litter/woody debris + stand biomass) at uncleared sites. Soil C decline (0–0.3m) accounted for approximately 7% of the average total C lost because of land clearing across all sites. Soil C stocks at uncleared sites were correlated with tree basal area, clay content and soil phosphorus (P) content. Changes in soil C after tree clearing were strongly correlated to initial soil C contents at the uncleared sites, and were associated with particular vegetation groups and soil types. Changes in soil N were strongly correlated with changes in soil C; however, the average change in soil N across all sites was not significant. Given the size of the C and N pools in rangeland soils, the factors that influence soil C and soil N dynamics in rangeland systems need to be better understood for the effective management of C stocks in these soils.

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Biochar from sugarcane residues: An overview of its sequestration potential in Sao Paulo, Brazil

10.5194/egusphere-egu2020-2880 ◽

2020 ◽

Author(s):

David Lefebvre ◽

Jeroen Meersmans ◽

Guy Kirk ◽

Adrian Williams

Keyword(s):

Soil Carbon ◽

C Sequestration ◽

Sao Paulo ◽

São Paulo ◽

Soil C ◽

Paulo State ◽

Sequestration Potential ◽

C Stocks ◽

C Stock ◽

Soil C Stock

Harvesting sugarcane (Saccharum officinarum) produces large quantities of biomass residues. We investigated the potential for converting these residues into biochar (recalcitrant carbon rich material) for soil carbon (C) sequestration. We modified a version of the RothC soil carbon model to follow changes in soil C stocks considering different amounts of fresh sugarcane residues and biochar (including recalcitrant and labile biochar fractions). We used Sao Paulo State (Brazil) as a case study due to its large sugarcane production and associated soil C sequestration potential.Mechanical harvesting of sugarcane fields leaves behind > 10 t dry matter of trash (leaves) ha-1 year-1. Although trash blanketing increases soil fertility, an excessive amount is detrimental and reduces the subsequent crop yield. After the optimal trash blanketing amount, sugarcane cultivation still produces 5.9 t C ha-1 year-1 of excess trash and bagasse (processing residues) which are available for subsequent use.The available residues could produce 2.5 t of slow-pyrolysis (550&#176;C) biochar C ha-1 year-1. The model predicts this could increase sugarcane field soil C stock on average by 2.4 &#177; 0.4 t C ha&#8209;1 year&#8209;1, after accounting for the climate and soil type variability across the State. Comparing different scenarios, we found that applying fresh residues into the field results in a smaller increase in soil C stock compared to the biochar because the soil C approaches a new equilibrium. For instance, adding 1.2 t of biochar C ha&#8209;1 year&#8209;1 along with 3.2 t of fresh residue C ha&#8209;1 year&#8209;1 increased the soil C stock by 1.8 t C ha&#8209;1 year&#8209;1 after 10 years of repeated applications. In contrast, adding 0.62 t of biochar C ha&#8209;1 year&#8209;1 with 4.5 t of fresh sugarcane residues C ha&#8209;1 year&#8209;1 increased the soil carbon soil stock by 1.4 t C ha&#8209;1 year&#8209;1 after 10 years of application. These are reductions 25% and 40% of the potential soil C accumulation rates compared with applying available residues as biochar.&#160; &#160;We also tested the sensitivity of the model to biochar-induced positive priming (i.e. increased mineralization of soil organic C) using published values. This showed that the C sequestration balance remains positive over the long term, even considering an extremely high positive-priming factor. Upscaling our results to the total 5 Mha of sugarcane in Sao Paulo State, biochar application could sequester up to 50 Mt of CO2 equivalent per year, representing 31% of the emissions attributed to the State in 2016.This study provides first insights into the sequestration potential of biochar application on sugarcane fields. Measurements of changes in soil C stocks in sugarcane field experiments are needed to further validate the model, and the emissions to implement the practice at large scale need to be taken into account. As the climate crisis grows, the need for greenhouse gas removal technologies becomes crucial. Assessing the net effectiveness of readily available technologies is essential to guide policy makers.&#160;&#160;

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Carbon and nitrogen in the silt-size fraction and its HCl-hydrolysis residues from coarse-textured Canadian boreal forest soils

Canadian Journal of Soil Science ◽

10.4141/cjss2013-082 ◽

2014 ◽

Vol 94 (2) ◽

pp. 157-168 ◽

Cited By ~ 4

Author(s):

Caroline M. Preston ◽

Charlotte E. Norris ◽

Guy M. Bernard ◽

David W. Beilman ◽

Sylvie A. Quideau ◽

...

Keyword(s):

Boreal Forest ◽

Soil Carbon ◽

Forest Soils ◽

Mineral Soil ◽

Size Fraction ◽

Soil C ◽

Carbon And Nitrogen ◽

Total Soil ◽

C Stocks ◽

Canadian Boreal Forest

Preston, C. M., Norris, C. E., Bernard, G. M., Beilman, D. W., Quideau, S. A. and Wasylishen, R. E. 2014. Carbon and nitrogen in the silt-size fraction and its HCl-hydrolysis residues from coarse-textured Canadian boreal forest soils. Can. J. Soil Sci. 94: 157–168. Improving the capacity to predict changes in soil carbon (C) stocks in the Canadian boreal forest requires better information on the characteristics and age of soil carbon, especially more slowly cycling C in mineral soil. We characterized C in the silt-size fraction, as representative of C stabilized by mineral association, previously isolated in a study of soil profiles of four sandy boreal jack pine sites. Silt-size fraction accounted for 13–31% of the total soil C and 12–51% of the total soil N content. Solid-state 13C nuclear magnetic resonance spectroscopy showed that silt C was mostly dominated by alkyl and O,N-alkyl C, with low proportions of aryl C in most samples. Thus, despite the importance of fire in this region, there was little evidence of storage of pyrogenic C. We used HCl hydrolysis to isolate the oldest C within the silt-size fraction. Consistent with previous studies, this procedure removed 21–74% of C and 74–93% of N, leaving residues composed mainly of alkyl and aryl C. However, it failed to isolate consistently old C; 11 out of 16 samples had recent 14C ages (fraction of modern 14C > 1), although C-horizon samples were older, with Δ14C from –17 to –476‰. Our results indicate relatively young ages for C associated with the silt-size fractions in these sites, for which mineral soil C storage may be primarily limited by good drainage and coarse soil texture, exacerbated by losses due to periodic wildfire.

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A Comparison of Soil Carbon Stocks of Intact and Restored Mangrove Forests in Northern Vietnam

Forests ◽

10.3390/f11060660 ◽

2020 ◽

Vol 11 (6) ◽

pp. 660

Author(s):

Pham Hong Tinh ◽

Nguyen Thi Hong Hanh ◽

Vo Van Thanh ◽

Mai Sy Tuan ◽

Pham Van Quang ◽

...

Keyword(s):

Soil Carbon ◽

Mangrove Forest ◽

Soil Core ◽

Mangrove Forests ◽

Soil C ◽

Northern Vietnam ◽

C Stocks ◽

C Stock ◽

Quang Ninh ◽

Soil C Stock

Background and Objectives: In northern Vietnam, nearly 37,100 hectares of mangroves were lost from 1964–1997 due to unsustainable harvest and deforestation for the creation of shrimp aquaculture ponds. To offset these losses, efforts in the late 1990s have resulted in thousands of hectares of mangroves being restored, but few studies to date have examined how effective these efforts are at creating restored mangrove forests that function similarly to the intact mangroves they are intended to replace. Materials and Methods: We quantified and compared soil carbon (C) stocks among restored (mono and mixed species) and intact mangrove forests in the provinces of Quang Ninh, Thai Binh, Nam Dinh and Thanh Hoa in northern Vietnam. A total of 96 soil cores up to a depth of 200 cm were collected every 25 m (25, 50, 75, 100, 125, and 150 m) along 16 linear transects that were 150 m long and perpendicular to the mangrove upland interface (six cores along each transect) at Quang Ninh (four transects), Thai Binh (five), Nam Dinh (four) and Thanh Hoa (three). Five-cm-long soil samples were then collected from the 0–15 cm, 15–30 cm, 30–50 cm, 50–100 cm, and >100 cm depth intervals of each soil core. Results: The study confirmed that the soil C stock of 20–25-year-old restored mangrove forest (217.74 ± 16.82 Mg/ha) was not significantly different from that of intact mangrove forest (300.68 ± 51.61 Mg/ha) (p > 0.05). Soil C stocks of Quang Ninh (323.89 ± 28.43 Mg/ha) were not significantly different from Nam Dinh (249.81 ± 19.09 Mg/ha), but both of those were significantly larger than Thai Binh (201.42 ± 27.65 Mg/ha) and Thanh Hoa (178.98 ± 30.82 Mg/ha) (p < 0.05). Soil C stock differences among provinces could be due to their different geomorphological characteristics and mangrove age. Soil C stocks did not differ among mangroves that were restored with mixed mangrove species (289.75 ± 33.28 Mg/ha), Sonneratia caseolaris (L.) Engl. (255.67 ± 13.11 Mg/ha) or Aegiceras corniculatum (L.) Blanco (278.15 ± 43.86 Mg/ha), but soil C stocks of those mangroves were significantly greater than that of Kandelia obovata Sheue, Liu & Yong (174.04 ± 20.38 Mg/ha) (p < 0.05). Conclusion: There were significant differences in the soil C stocks of mangrove forests among species and provinces in northern Vietnam. The soil C stock of 20–25-year-old restored mangrove forest was not significantly different from that of intact mangrove forest.

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Vinasse application and cessation of burning in sugarcane management can have positive impact on soil carbon stocks

PeerJ ◽

10.7717/peerj.5398 ◽

2018 ◽

Vol 6 ◽

pp. e5398 ◽

Cited By ~ 1

Author(s):

Caio F. Zani ◽

Arlete S. Barneze ◽

Andy D. Robertson ◽

Aidan M. Keith ◽

Carlos E.P. Cerri ◽

...

Keyword(s):

Soil Carbon ◽

Greenhouse Gas ◽

Management Practices ◽

Positive Impact ◽

Clay Fraction ◽

Bioenergy Crops ◽

Soil C ◽

Sequestration Potential ◽

C Stocks ◽

Management Changes

Bioenergy crops, such as sugarcane, have the potential to mitigate greenhouse gas emissions through fossil fuel substitution. However, increased sugarcane propagation and recent management changes have raised concerns that these practices may deplete soil carbon (C) stocks, thereby limiting the net greenhouse gas benefit. In this study, we use both a measured and modelled approach to evaluate the impacts of two common sugarcane management practices on soil C sequestration potential in Brazil. We explore how transitions from conventional (mineral fertiliser/burning) to improved (vinasse application/unburned) practices influence soil C stocks in total and in physically fractionated soil down to one metre. Results suggest that vinasse application leads to an accumulation of soil C of 0.55 Mg ha−1yr−1 at 0–30 cm depth and applying unburned management led to gains of ∼0.7 Mg ha−1yr−1 at 30–60 cm depth. Soil C concentration in the Silt+Clay fraction of topsoil (0–20 cm) showed higher C content in unburned management but it did not differ under vinasse application. The CENTURY model was used to simulate the consequences of management changes beyond the temporal extent of the measurements. Simulations indicated that vinasse was not the key factor driving increases in soil C stocks but its application may be the most readily available practice to prevent the soil C losses under burned management. Furthermore, cessation of burning may increase topsoil C by 40% after ∼50 years. These are the first data comparing different sugarcane management transitions within a single area. Our findings indicate that both vinasse application and the cessation of burning can play an important role in reducing the time required for sugarcane ethanol production to reach a net C benefit (payback time).

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Impacts of poplar and alder on soil carbon in pasture-tree systems

NZGA: Research and Practice Series ◽

10.33584/rps.16.2016.3231 ◽

2016 ◽

Vol 16 ◽

pp. 197-202

Author(s):

G.B. Douglas ◽

R.E. Vibart ◽

A.D. Mackay ◽

M.B. Dodd ◽

I.R. Mcivor

Keyword(s):

Carbon Sequestration ◽

Soil Carbon ◽

Greenhouse Gas ◽

Open Systems ◽

Ghg Mitigation ◽

Soil C ◽

Hill Country ◽

C Storage ◽

C Stocks ◽

Significant Difference

Wide-spaced trees on pastoral land (pasture-tree (PT) systems) are a widespread feature of many farmed landscapes. They offer the potential to increase carbon (C) storage, with implications for reducing atmospheric CO2-C. The effect of PT systems on soil C stocks to 1 m depth was determined for trees aged 14-16 years at densities of 73-111 stems per hectare at four North Island sites (two with poplar, two with alder). Across sites, mean soil C concentration was 1.9-8.5% and mean total soil C mass was 120-455 tonnes C/ha. For alder systems, total C mass of PT was 37% less than adjacent pasture (Open) at Poukawa (120 versus 189 tonnes C/ha), whereas at Ruakura, there was no significant difference between systems. Total C mass of PT systems involving poplar did not vary significantly from adjacent Open systems at Tikokino (328 versus 352 tonnes C/ha) and Woodville (154 versus 202 tonnes C/ha). Soil at 0.3-1.0 m depth comprised up to half of total C mass. Results suggested that poplar and alder had different effects on soil C. Keywords: pastoral hill country, wide-spaced trees, carbon sequestration, greenhouse gas (GHG) mitigation

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Stratifying soils into pedogenically similar categories for modeling forest soil carbon

Canadian Journal of Soil Science ◽

10.4141/cjss07099 ◽

2008 ◽

Vol 88 (4) ◽

pp. 501-516 ◽

Cited By ~ 19

Author(s):

C H Shaw ◽

E. Banfield ◽

W A Kurz

Keyword(s):

Soil Carbon ◽

Forest Soil ◽

Scientific Basis ◽

Soil C ◽

Orthogonal Contrasts ◽

Carbon Modeling ◽

Ecosystem Carbon ◽

C Dynamics ◽

C Stocks ◽

Pedogenic Processes

Most forest ecosystem carbon (C) models are designed to estimate total ecosystem C including soil C stocks and fluxes. Stratification by tree species is often used in these models to reduce uncertainty, but the potential of stratification by soil taxon has received little attention. This potential can be realized only if meaningful modeling strata are identified. Therefore, the objectives of this study were: (a) to distinguish strata of soil C modeling cateogories (SCMC) on the basis of soil C stocks of taxonomic categories that are characterized by similar pedogenic processes important to C dynamics, and (b) to review the literature to test the robustness of the SCMC scheme. Carbon stocks of 1383 forest soil pedons were analyzed by multiple means comparisons for soil orders and by orthogonal contrasts between pedologically related sets of subgroups within soil orders. Eleven SCMCs were distinguished with mean total C stocks varying from 325 ± 37.2 t ha-1 for the gleyed Cryosol SCMC to 94 ± 3.9 t ha-1 for the Brunisolic Gray Luvisol SCMC. A review of the literature relevant to each SCMC demonstrated that there is a scientific basis for using these strata to model forest soil C dynamics. Key words: Forest soil, carbon, modeling, pedology, genesis

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Linking Vegetation, Soil Carbon Stocks, and Earthworms in Upland Coniferous–Broadleaf Forests

Forests ◽

10.3390/f12091179 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1179

Author(s):

Anastasiia I. Kuznetsova ◽

Anna P. Geraskina ◽

Natalia V. Lukina ◽

Vadim E. Smirnov ◽

Elena V. Tikhonova ◽

...

Keyword(s):

Soil Carbon ◽

Carbon Stocks ◽

Mineral Layer ◽

Forest Zone ◽

Soil C ◽

C Stocks ◽

European Part Of Russia ◽

Organic Horizons ◽

Soil Carbon Stocks ◽

The Impact

Linking vegetation, soil biota, and soil carbon stocks in forests has a high predictive value. The specific aim of this study was to identify the relationships between vegetation, earthworms, and soil carbon stocks in nine types of forests dominating autonomous landscape positions in a coniferous–broadleaf forest zone of the European part of Russia. Mountain forests were selected in the Northwest Caucasus, while plain forests were selected in Bryansk Polesie and on the Moskva-Oka plain. One-way analysis of variance (ANOVA) and v-tests were used to assess the impact of different factors on soil C stocks. To assess the contribution of vegetation, litter quality, and earthworms to variation of carbon stocks in organic (FH-layer) and mineral layer (0–50 cm), the method of hierarchical partitioning was performed. The highest C stocks in the organic horizons were associated with the low-quality litter, i.e., with a low base saturation, high acidity, and wide C/N ratio. The highest soil C stocks in the mineral layers were found in mixed forests with the highest richness of plant species, producing litterfall of different quality. The С stock in the organic horizon was negatively related to the biomass of worms that process the litter, while the carbon stock in the mineral layers was positively related to the biomass of worms whose life activity is related to the mineral layers. These findings demonstrated the substantial influence of plants producing a litter of different quality, and of earthworms, belonging to different functional groups, on soil С stocks in coniferous–broadleaf forests.

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Importance of resilient pastures for New Zealand’s agricultural soil carbon stocks

NZGA: Research and Practice Series ◽

10.33584/rps.17.2021.3455 ◽

2021 ◽

Vol 17 ◽

Author(s):

Aaron Wall ◽

Jordan Goodrich ◽

Louis Schipper

Keyword(s):

Soil Carbon ◽

Management Practices ◽

C Sequestration ◽

Co2 Uptake ◽

Soil C ◽

Supplemental Feed ◽

Natural Processes ◽

C Stocks ◽

Soil Carbon Stocks ◽

Below Ground

New Zealand’s agricultural pastures contain significant soil carbon (C) stocks that are susceptible to change when impacted by management and natural processes (e.g., climate). Inputs of C to these pastoral soils is through photosynthetic uptake of atmospheric CO2 either on-site or elsewhere. Changes in soil C stocks are in response to the management of the system that alters the input-output balance. Increasing the resilience of pastures to climatic events such as hot and dry summers or cool and wet winters can increase inputs of C to the soil while sustaining above-ground production and so provide an opportunity for C sequestration. Furthermore, increased pasture for grazing can reduce the need for management practices identified as detrimental for soil C stocks such as irrigation or the production of cropped supplemental feed. A reduction in the need for renewal and its associated soil C losses, and the establishment of a more diverse sward, especially if deeper-rooting species are included, has the potential for increasing soil C stocks provided the diversity can be maintained. From a soil C perspective, a resilient pasture maximises CO2 uptake to ensure adequate above- and below-ground inputs to maintain or increase soil C stocks and minimise the need for management activities detrimental to soil C.

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