scholarly journals Organic Amendments Alter Long-Term Turnover and Stability of Soil Carbon: Perspectives from a Data-Model Integration

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2134
Author(s):  
Guocheng Wang ◽  
Zhongkui Luo
Keyword(s):  
Carbon Sequestration ◽  
Soil Carbon ◽  
Agricultural Soils ◽  
Organic Amendments ◽  
Climate Conditions ◽  
Local Soil ◽  
Microbial Carbon ◽  
Use Efficiency

Organic amendment (OA) additions may profoundly regulate the turnover behaviours of soil organic carbon (SOC). Explicit understanding of such role of OA is crucial for accurately assessing the potential of carbon sequestration in agricultural soils. To explore the effects of OA additions on the detailed SOC stabilization and destabilization processes, we collected SOC measurements from 29 trials with experimental duration ranging from 14 to 85 years across the globe. Using these datasets, we constrained a soil carbon model to analyse SOC turnover and built-up processes as impacted by OA additions. We found that OA generally decreases microbial carbon use efficiency (CUE) and the fraction of inert SOC that is resistant to decomposition (finert), but has divergent effects on the decay rate of humic SOC (khum). Across the sites, there was great variability in the effects of OA on CUE, khum, and finert, which can be largely explained by local soil and climate conditions and the quantity and quality of OA. Long-term simulations suggested that, without considering the effects of OA on CUE, khum, and finert, the effectiveness of OA additions for carbon sequestration could be largely overestimated. Our results suggest that the strong site-specific regulations of OA on SOC dynamics as demonstrated in this study must be properly considered and better constrained by observational data when assessing SOC sequestration in agricultural soils under the management of OA additions.

scholarly journals Long-term pattern and magnitude of soil carbon feedback to the climate system in a warming world

Science ◽  
2017 ◽  
Vol 358 (6359) ◽  
pp. 101-105 ◽  
Author(s):  
J. M. Melillo ◽  
S. D. Frey ◽  
K. M. DeAngelis ◽  
W. J. Werner ◽  
M. J. Bernard ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Microbial Community Composition ◽  
Climate System ◽  
Carbon Loss ◽  
Soil Warming ◽  
Carbon Dioxide Fluxes ◽  
Microbial Carbon ◽  
Use Efficiency ◽  
Warming World

In a 26-year soil warming experiment in a mid-latitude hardwood forest, we documented changes in soil carbon cycling to investigate the potential consequences for the climate system. We found that soil warming results in a four-phase pattern of soil organic matter decay and carbon dioxide fluxes to the atmosphere, with phases of substantial soil carbon loss alternating with phases of no detectable loss. Several factors combine to affect the timing, magnitude, and thermal acclimation of soil carbon loss. These include depletion of microbially accessible carbon pools, reductions in microbial biomass, a shift in microbial carbon use efficiency, and changes in microbial community composition. Our results support projections of a long-term, self-reinforcing carbon feedback from mid-latitude forests to the climate system as the world warms.

The impact of porosity on organic matter cycling in a two-dimensional porous medium 

2021 ◽  
Author(s):  
Hanbang Zou ◽  
Pelle Ohlsson ◽  
Edith Hammer
Keyword(s):  
Porous Medium ◽  
Organic Matter ◽  
Carbon Sequestration ◽  
Soil Carbon ◽  
Pore Network ◽  
Pore Scale ◽  
Decomposition Of Organic Matter ◽  
Organic Matter Cycling ◽  
The Impact

<p>Carbon sequestration has been a popular research topic in recent years as the rapid elevation of carbon emission has significantly impacted our climate. Apart from carbon capture and storage in e.g. oil reservoirs, soil carbon sequestration offers a long term and safe solution for the environment and human beings. The net soil carbon budget is determined by the balance between terrestrial ecosystem sink and sources of respiration to atmospheric carbon dioxide. Carbon can be long term stored as organic matters in the soil whereas it can be released from the decomposition of organic matter. The complex pore networks in the soil are believed to be able to "protect" microbial-derived organic matter from decomposition. Therefore, it is important to understand how soil structure impacts organic matter cycling at the pore scale. However, there are limited experimental studies on understanding the mechanism of physical stabilization of organic matter. Hence, my project plan is to create a heterogeneous microfluidic porous microenvironment to mimic the complex soil pore network which allows us to investigate the ability of organisms to access spaces starting from an initial ecophysiological precondition to changes of spatial accessibility mediated by interactions with the microbial community.</p><p>Microfluidics is a powerful tool that enables studies of fundamental physics, rapid measurements and real-time visualisation in a complex spatial microstructure that can be designed and controlled. Many complex processes can now be visualized enabled by the development of microfluidics and photolithography, such as microbial dynamics in pore-scale soil systems and pore network modification mimicking different soil environments – earlier considered impossible to achieve experimentally. The microfluidic channel used in this project contains a random distribution of cylindrical pillars of different sizes so as to mimic the variations found in real soil. The randomness in the design creates various spatial availability for microbes (preferential flow paths with dead-end or continuous flow) as an invasion of liquids proceeds into the pore with the lowest capillary entry pressure. In order to study the impact of different porosity in isolation of varying heterogeneity of the porous medium, different pore size chips that use the same randomly generated pore network is created. Those chips have the same location of the pillars, but the relative size of each pillar is scaled. The experiments will be carried out using sterile cultures of fluorescent bacteria, fungi and protists, synthetic communities of combinations of these, or a whole soil community inoculum. We will quantify the consumption of organic matter from the different areas via fluorescent substrates, and the bio-/necromass produced. We hypothesise that lower porosity will reduce the net decomposition of organic matter as the narrower pore throat limits the access, and that net decomposition rate at the main preferential path will be higher than inside branches</p>

scholarly journals Additional Benefits of Community Managed Forest: A Case Study of Champadevi Community Forest

2012 ◽  
Vol 12 ◽  
pp. 127-132
Author(s):  
Bhanu B Panthi
Keyword(s):  
Carbon Sequestration ◽  
Significant Contribution ◽  
Research Area ◽  
Environmental Benefits ◽  
Managed Forests ◽  
Managed Forest ◽  
Community Based

This research attempts to identify the existing condition of the community managed forest based on the assumption that it will serve as a proxy for the condition of other forests in the mid hills region of Nepal. The research area has an atypical variation in altitude and diverse pattern of vegetation. This study mainly focuses on estimating carbon content in the forest and identifying the species that has more carbon storage capacity. The research signifies the role of forests in mitigation of ‘Global warming’ and ‘Climate change’ by storing carbon in tree biomass. These types of community based forest management programs are significant for their additional carbon sequestration through the avoidance of deforestation and degradation. The carbon sequestration have a significant contribution to environmental benefits, any shrinkage of forests have an enormous impact on CO2 emission with long term consequences. Thus, the development and expansion of community managed forests provide many benefits to the adjacent community and globally at large.DOI: http://dx.doi.org/10.3126/njst.v12i0.6490 Nepal Journal of Science and Technology 12 (2011) 127-32 

Soil carbon sequestration through crops rotation in a Mediterranean Cambisols: measurement and modelling

2021 ◽  
Author(s):  
Enrico Balugani ◽  
Martina Maines ◽  
Denis Zannoni ◽  
Alessandro Buscaroli ◽  
Diego Marazza
Keyword(s):  
Carbon Sequestration ◽  
Soil Carbon ◽  
Crop Rotation ◽  
Soil Carbon Sequestration ◽  
Crop Rotations ◽  
Subtropical Climate ◽  
Sequestration Potential ◽  
Rothc Model ◽  
Periodic Fluctuations

<p>Soil carbon sequestration (SCS) has been identified by the IPCC as one of the most promising and cheap methodology to reduce atmospheric CO<sub>2</sub>. Moreover, an increase in soil organic carbon (SOC) levels improves soil quality by increasing soil structure (and, hence, resistance to erosion) and promoting soil ecosystems services like water retention, productivity, and biodiversity. Various agricultural techniques are available to increase SOC; among them, crop rotation can improve SOC through soil coverage, changes in water regimes, increase in both carbon inputs, and increase in soil aggregates formation.</p><p>SOC dynamic models, such as RothC, have been suggested by the IPCC as a way to evaluate the SCS potentials of different soils. Such models could also be used to evaluate the sequestration potential of different agricultural practices. Moreover RothC allows to estimate the time within which the SOC variation, due to a certain agronomic management, can be considered significant as measurable above a threshold value.</p><p>In this study, we evaluated the SOC changes for different crop rotations through direct measurements and RothC modelling, with the objective of: (a) estimating their SCS potential, and (b) propose a robust monitoring methodology for SCS practices. We performed the study in an agricultural field close to Ravenna (Italy) characterized by Cambisols and humid subtropical climate. Soil carbon content was assessed before the setup of the crop rotation, and after 3 years of rotation. A RothC model was calibrated with field data, and used to estimate SOC dynamics to 50 years, in order to assess long-term SCS. The model results were also used to assess the best methodology to estimate the SOC variation significance.</p><p>The measured SOC was similar to the equilibrium SOC predicted by the RothC model, on average, for the crop rotations. The measurements showed that the SOC, already low at the beginning of the experiment, further decreased due to the crop rotation practice. Of those tested, the best for SCS involves the following crops: corn, soybeans, wheat on tilled soil, and soybeans; while the worst is with corn, wheat on tilled soil, and wheat on untilled soil. However, the SOC variations predicted by RothC for the various rotations were too small to be observable in the field during experimentation. This could be due both to the uncertainty associated with SOC sampling and analysis, and to the short duration of the experiment. The moving average computations on the simulation values allowed us to assess the time required to measure the long-term trend of SOC variation as significant with respect to the environmental background, instrumental error, and SOC periodic fluctuations. That time was estimated to range from 8 to 50 years, changing depending on the rotation type. Periodic fluctuations in SOC should be carefully considered in a monitoring protocol to assess SCS.</p>

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