Redox-driven changes in organic C stabilization and Fe mineral transformations in temperate hydromorphic soils

Redox-driven changes in Fe crystallinity and speciation may affect soil organic matter (SOM) stabilization and carbon (C) turnover, with consequent influence on global terrestrial soil organic carbon (SOC) cycling.&#160;Under reducing conditions, increasing concentrations of Fe(II) released in solution from the reductive dissolution of Fe (hydr)oxides may accelerate ferrihydrite transformation, although our understanding of the influence of SOM on these transformations is still lacking.&#160;Here, we evaluated abiotic Fe(II)-catalyzed mineralogical changes in Fe (hydr)oxides in bulk soils and size-fractionated SOM pools (for comparison, fine silt plus clay, FSi+Cl, and fine sand, FSa) of an agricultural soil, unamended or amended with biochar, municipal solid waste compost, and a combination of both.&#160;FSa fractions showed the most significant Fe(II)-catalyzed ferrihydrite transformations with the consequent production of well-ordered Fe oxides irrespective of soil amendment, with the only exception being the compost-amended soils. In contrast, poorly crystalline ferrihydrite still constituted ca. 45% of the FSi+Cl fractions of amended soils, confirming the that the higher SOM content in this fraction inhibits atom exchange between aqueous Fe(II) and the solid phase. Building on our knowledge of Fe(II)-catalyzed mineralogical changes in simple systems, our results evidenced that the mechanisms of abiotic Fe mineral transformations in bulk soils depend on Fe mineralogy, organic C content and quality, and organo-mineral associations that exist across particle-size SOM pools. Our results underline that in the fine fractions the increase in SOM due to organic amendments can contribute to limiting abiotic Fe(II)-catalyzed ferrihydrite transformation, while coarser particle-size fractions represent an understudied pool of SOM subjected to Fe mineral transformations.&#160;

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Mineral transformations and magnetic properties : example of an uranium rich front of oxido-reduction

Bulletin de Minéralogie ◽

10.3406/bulmi.1987.7979 ◽

1987 ◽

Vol 110 (2) ◽

pp. 187-195

Author(s):

Olivier Mergaux ◽

Jean-Claude Samama

Keyword(s):

Magnetic Properties ◽

Mineral Transformations

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Faculty Opinions recommendation of Evidence for the respiration of ancient terrestrial organic C in northern temperate lakes and streams.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717960185.793463370 ◽

2012 ◽

Author(s):

Gilles Pinay

Keyword(s):

Temperate Lakes ◽

Organic C

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Sustainable Management of Soil for Carbon Sequestration

Science & Technology Journal ◽

10.22232/stj.2017.05.02.10 ◽

2017 ◽

Vol 5 (2) ◽

pp. 132-140 ◽

Cited By ~ 1

Author(s):

Kewat Sanjay Kumar ◽

Keyword(s):

Carbon Sequestration ◽

Soil Carbon ◽

Sustainable Management ◽

Management Practices ◽

Atmospheric Co2 ◽

Carbon Pools ◽

Carbon Stabilization ◽

Organic C ◽

Soil Ecosystems ◽

C Stocks

Mechanisms governing carbon stabilization in soils have received a great deal of attention in recent years due to their relevance in the global carbon cycle. Two thirds of the global terrestrial organic C stocks in ecosystems are stored in below ground components as terrestrial carbon pools in soils. Furthermore, mean residence time of soil organic carbon pools have slowest turnover rates in terrestrial ecosystems and thus there is vast potential to sequester atmospheric CO2 in soil ecosystems. Depending upon soil management practices it can be served as source or sink for atmospheric CO2. Sustainable management systems and practices such as conservation agriculture, agroforestry and application of biochar are emerging and promising tools for soil carbon sequestration. Increasing soil carbon storage in a system simultaneously improves the soil health by increase in infiltration rate, soil biota and fertility, nutrient cycling and decrease in soil erosion process, soil compaction and C emissions. Henceforth, it is vital to scientifically explore the mechanisms governing C flux in soils which is poorly understood in different ecosystems under anthropogenic interventions making soil as a potential sink for atmospheric CO2 to mitigate climate change. Henceforth, present paper aims to review basic mechanism governing carbon stabilization in soils and new practices and technological developments in agricultural and forest sciences for C sequestration in terrestrial soil ecosystems.

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Nutrient Cycling and Energy Flow in Grasslands

10.1093/oso/9780198744511.003.0004 ◽

2018 ◽

Author(s):

Brian J. Wilsey

Keyword(s):

Energy Flow ◽

Animal Species ◽

Net Primary Productivity ◽

Growing Season ◽

C4 Plant ◽

Geographic Scale ◽

Organic C ◽

Natural Forms ◽

Belowground Productivity ◽

Remote Sensing Techniques

Net primary productivity (NPP) is the amount of C or biomass that accumulates over time and is photosynthesis—autotroph respiration. Annual NPP is estimated by summing positive biomass increments across time periods during the growing season, including offtake to herbivores, which can be high in grasslands. Remote sensing techniques that are used to assess NPP are discussed by the author. Belowground productivity can be high in grasslands, and it is important to carbon storage. Across grasslands on a geographic scale, NPP, N mineralization, and soil organic C all increase with annual precipitation. Within regions, NPP can be strongly affected by the proportion of C4 plant species and animal species composition and diversity. Humans are adding more N to the environment than all the natural forms of addition (fixation and lightning) combined. Animals, especially herbivores, can have strong effects on how plants respond to changes in changes in resource availability.

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Corrigendum to: Conservation agriculture effects on soil properties and crop productivity in a semiarid region of India

Soil Research ◽

10.1071/sr18145_co ◽

2019 ◽

Vol 57 (2) ◽

pp. 200 ◽

Cited By ~ 1

Author(s):

J. Somasundaram ◽

M. Salikram ◽

N. K. Sinha ◽

M. Mohanty ◽

R. S. Chaudhary ◽

...

Keyword(s):

Soil Properties ◽

Management Practices ◽

Crop Yields ◽

Cropping Systems ◽

Soil Layer ◽

Conservation Agriculture ◽

Semiarid Region ◽

Reduced Tillage ◽

Organic C ◽

Residue Retention

Conservation agriculture (CA) including reduced or no-tillage and crop residue retention, is known to be a self–sustainable system as well as an alternative to residue burning. The present study evaluated the effect of reduced tillage coupled with residue retention under different cropping systems on soil properties and crop yields in a Vertisol of a semiarid region of central India. Two tillage systems – conventional tillage (CT) with residue removed, and reduced tillage (RT) with residue retained – and six major cropping systems of this region were examined after 3 years of experimentation. Results demonstrated that soil moisture content, mean weight diameter, percent water stable aggregates (>0.25mm) for the 0–15cm soil layer were significantly (Pmoderately labile>less labile. At the 0–15cm depth, the contributions of moderately labile, less labile and non-labile C fractions to total organic C were 39.3%, 10.3% and 50.4% respectively in RT and corresponding values for CT were 38.9%, 11.7% and 49.4%. Significant differences in different C fractions were observed between RT and CT. Soil microbial biomass C concentration was significantly higher in RT than CT at 0–15cm depth. The maize–chickpea cropping system had significantly (P–1 followed by soybean+pigeon pea (2:1) intercropping (3.50 t ha–1) and soybean–wheat cropping systems (2.97 t ha–1). Thus, CA practices could be sustainable management practices for improving soil health and crop yields of rainfed Vertisols in these semiarid regions.

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Reference carbon cycle dataset for typical Chinese forests via colocated observations and data assimilation

Scientific Data ◽

10.1038/s41597-021-00826-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Honglin He ◽

Rong Ge ◽

Xiaoli Ren ◽

Li Zhang ◽

Qingqing Chang ◽

...

Keyword(s):

Northern Hemisphere ◽

Global Climate ◽

Meteorological Data ◽

C Sequestration ◽

Research Network ◽

Soil Biology ◽

Area Index ◽

Ecosystem Research ◽

Organic C ◽

C Cycle

AbstractChinese forests cover most of the representative forest types in the Northern Hemisphere and function as a large carbon (C) sink in the global C cycle. The availability of long-term C dynamics observations is key to evaluating and understanding C sequestration of these forests. The Chinese Ecosystem Research Network has conducted normalized and systematic monitoring of the soil-biology-atmosphere-water cycle in Chinese forests since 2000. For the first time, a reference dataset of the decadal C cycle dynamics was produced for 10 typical Chinese forests after strict quality control, including biomass, leaf area index, litterfall, soil organic C, and the corresponding meteorological data. Based on these basic but time-discrete C-cycle elements, an assimilated dataset of key C cycle parameters and time-continuous C sequestration functions was generated via model-data fusion, including C allocation, turnover, and soil, vegetation, and ecosystem C storage. These reference data could be used as a benchmark for model development, evaluation and C cycle research under global climate change for typical forests in the Northern Hemisphere.

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Effects of green-manure and tillage management on soil microbial community composition, nutrients and tree growth in a walnut orchard

Scientific Reports ◽

10.1038/s41598-021-96472-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ningguang Dong ◽

Guanglong Hu ◽

Yunqi Zhang ◽

Jianxun Qi ◽

Yonghao Chen ◽

...

Keyword(s):

Microbial Community ◽

Green Manure ◽

Rhizosphere Soil ◽

Green Manures ◽

Hairy Vetch ◽

Mineral N ◽

Total N ◽

Organic C ◽

Nutrient Contents ◽

Walnut Tree

AbstractThis study characterized the effect of green manures (February orchid, hairy vetch, rattail fescue and a no-green-manure control) and the termination method (flail or disk) on nutrient contents, enzyme activities, microbial biomass, microbial community structure of rhizosphere soil and vegetative growth of walnut tree. All three selected green manures significantly enhanced the water content, organic C, total N and available P. The rattail fescue significantly decreased the mineral N. Total organic C, total N, mineral N and available P were significantly greater under flail than under disk. Hairy vetch and February orchid significantly improved levels of soil β-glucosidase, N-acetyl-glucosaminidase and acid phosphatase activity, whereas rattail fescue improved only β-glucosidase activity. All of the green manures significantly decreased phenoloxidase activity. β-glucosidase, N-acetyl-glucosaminidase and acid phosphatase activities were significantly greater under flail relative to disk. The termination method had no significant effect on phenoloxidase activity. The different types of green manures and termination methods significantly altered the soil microbial biomass and microbial community structure. The green-manure treatments were characterized by a significantly greater abundance of Gram-positive (Gram +) bacteria, total bacteria and saprophytic fungi compared to the control. Hairy vetch significantly decreased the abundance of arbuscular mycorrhizal fungi (AMF) while February orchid and rattail fescue increased their abundance compared to the no-green-manure treatment. The abundance rates of Gram+ bacteria, actinomycetes, saprophytic fungi and AMF were significantly greater in soils under flail than under disk. In terms of vegetative growth of walnut tree, hairy vetch showed the greatest positive effects. The growth of walnut tree was significantly greater under flail relative to disk. Our results indicate that green-manure application benefits the rhizosphere soil micro-ecology, rhizosphere soil nutrient contents and tree growth. Overall, the hairy vetch and flail combined treatment is recommended for walnut orchards in northern China.

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Effect of Soil Management on Erosion in Mountain Vineyards (N-W Italy)

Sustainability ◽

10.3390/su13041991 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1991

Author(s):

Silvia Stanchi ◽

Odoardo Zecca ◽

Csilla Hudek ◽

Emanuele Pintaldi ◽

Davide Viglietti ◽

...

Keyword(s):

Soil Erosion ◽

Management Practices ◽

Soil Management ◽

Buffer Strips ◽

Total N ◽

Organic C ◽

Erosion Rates ◽

Soil Ecosystem Services ◽

Erosion Mitigation ◽

Management Approaches

We studied the effects of three soil management approaches (permanent grassing, chemical weeding, and buffer strips), and the additional impact of tractor passage on soil erosion in a sloping vineyard located in the inner part of Aosta Valley (N-W Italian Alps). The vineyard rows were equipped with a sediment collection system with channels and barrel tanks. A total of 12 events with sediment production were observed across 6 years, and the collected sediments were weighted and analyzed. Average erosion rates ranged from negligible (mainly in grassed rows) to 1.1 t ha−1 per event (after weeding). The most erosive event occurred in July 2015, with a total rainfall of 32.2 mm, of which 20.1 were recorded in 1 h. Despite the limited number of erosive events observed, and the low measured erosion rates, permanent grassing reduced soil erosion considerably with respect to weeding; buffering had a comparable effect to grassing. The tractor passage, independent of the soil management approaches adopted, visibly accelerated the erosion process. The collected sediments were highly enriched in organic C, total N, and fine size fractions, indicating a potential loss of fertility over time. Despite the measured erosion rates being low over the experiment’s duration, more severe events are well documented in the recent past, and the number of intense storms is likely to increase due to climate change. Thus, the potential effects of erosion in the medium and long term need to be limited to a minimum rate of soil loss. Our experiment helped to compare soil losses by erosion under different soil management practices, including permanent grassing, i.e., a nature-based erosion mitigation measure. The results of the research can provide useful indications for planners and practitioners in similar regions, for sustainable, cross-sectoral soil management, and the enhancement of soil ecosystem services.

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Characterization of Soil Carbon Stocks in the City of Johannesburg

Land ◽

10.3390/land10010083 ◽

2021 ◽

Vol 10 (1) ◽

pp. 83

Author(s):

Kelebohile Rose Seboko ◽

Elmarie Kotze ◽

Johan van Tol ◽

George van Zijl

Keyword(s):

Bulk Density ◽

Soil Depth ◽

Soil Productivity ◽

Rapid Urbanization ◽

Organic C ◽

C Stocks ◽

Shallow Soils ◽

Deep Soils ◽

Soc Stocks ◽

Soil Groups

Soil organic carbon (SOC) is a crucial indicator of soil health and soil productivity. The long-term implications of rapid urbanization on sustainability have, in recent years, raised concern. This study aimed to characterize the SOC stocks in the Johannesburg Granite Dome, a highly urbanized and contaminated area. Six soil hydropedological groups; (recharge (deep), recharge (shallow), responsive (shallow), responsive (saturated), interflow (A/B), and interflow (soil/bedrock)) were identified to determine the vertical distribution of the SOC stocks and assess the variation among the soil groups. The carbon (C) content, bulk density, and soil depth were determined for all soil groups, and thereafter the SOC stocks were calculated. Organic C stocks in the A horizon ranged, on average, from 33.55 ± 21.73 t C ha−1 for recharge (deep) soils to 17.11 ± 7.62 t C ha−1 for responsive (shallow) soils. Higher C contents in some soils did not necessarily indicate higher SOC stocks due to the combined influence of soil depth and bulk density. Additionally, the total SOC stocks ranged from 92.82 ± 39.2 t C ha−1 for recharge (deep) soils to 22.81 ± 16.84 t C ha−1 for responsive (shallow) soils. Future studies should determine the SOC stocks in urban areas, taking diverse land-uses and the presence of iron (Fe) oxides into consideration. This is crucial for understanding urban ecosystem functions.

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