scholarly journals Permafrost carbon−climate feedback is sensitive to deep soil carbon decomposability but not deep soil nitrogen dynamics

2015 ◽  
Vol 112 (12) ◽  
pp. 3752-3757 ◽  
Author(s):  
Charles D. Koven ◽  
David M. Lawrence ◽  
William J. Riley
Keyword(s):  
Soil Nitrogen ◽  
Carbon Balance ◽  
Nitrogen Availability ◽  
Nitrogen Dynamics ◽  
Permafrost Region ◽  
Deep Soil ◽  
Surface Soils ◽  
Permafrost Thaw ◽  
The Future ◽  
The Impact

Permafrost soils contain enormous amounts of organic carbon whose stability is contingent on remaining frozen. With future warming, these soils may release carbon to the atmosphere and act as a positive feedback to climate change. Significant uncertainty remains on the postthaw carbon dynamics of permafrost-affected ecosystems, in particular since most of the carbon resides at depth where decomposition dynamics may differ from surface soils, and since nitrogen mineralized by decomposition may enhance plant growth. Here we show, using a carbon−nitrogen model that includes permafrost processes forced in an unmitigated warming scenario, that the future carbon balance of the permafrost region is highly sensitive to the decomposability of deeper carbon, with the net balance ranging from 21 Pg C to 164 Pg C losses by 2300. Increased soil nitrogen mineralization reduces nutrient limitations, but the impact of deep nitrogen on the carbon budget is small due to enhanced nitrogen availability from warming surface soils and seasonal asynchrony between deeper nitrogen availability and plant nitrogen demands. Although nitrogen dynamics are highly uncertain, the future carbon balance of this region is projected to hinge more on the rate and extent of permafrost thaw and soil decomposition than on enhanced nitrogen availability for vegetation growth resulting from permafrost thaw.

Carbon and Nitrogen Dynamics in Mexican Management Forest: Simulation of Biomass Harvesting and C and N Amendments

2021 ◽  
Author(s):  
Maria-Cristina Ordoñez ◽  
Leopoldo Galicia ◽  
Karla Valladares-Samperio
Keyword(s):  
Forest Management ◽  
Aboveground Biomass ◽  
Nitrogen Availability ◽  
Organic Amendments ◽  
Residue Management ◽  
Mineral N ◽  
Soil Microbial ◽  
Silvicultural Management ◽  
The Future ◽  
The Impact

Abstract Sustainable silvicultural management requires the maintenance of long-term ecosystem processes. We used the CENTURY model to simulate the impact of wood extraction and organic amendments on aboveground biomass, carbon (C) storage, and the availability of nitrogen (N) in the two dominant silvicultural methods in Mexico: the silvicultural development method (SDM) and irregular forest management (IFM). The values of the mean absolute percentage error for the SDM and IFM were 2.1% and 3.3% for C in aboveground biomass, 5.7% and 5.0% for soil organic carbon (SOC), and 14.9% and 21.6% for N, respectively. Simulation for the SDM (1967–2068) suggested a reduction of ~7% in C in soil, microbial biomass, and litter, 9% in aboveground biomass C, and ~20% in the mineral N available. For IFM, the simulation (2009–2019) suggested a reduction of 14% in the accumulation of aboveground biomass and 13% in the mineral N available. Simulation of the adoption of management practices suggested that N mineral availability would increase by 2%–3% without drastically reducing the SOC, improving aboveground biomass production by ~7%, in each management system. Study Implications In Mexico, current silvicultural management is causing alterations in the biological and chemical processes of the soil, but the future impacts on the production of forest wood and loss of fertility cannot be estimated by direct measurements. We simulated two silvicultural management alternatives with two rotation cycles and measured the response in terms of SOC, nitrogen availability, and aboveground biomass. The model shows that improving forest residue management by adding organic amendments to the soil would counteract changes in soil microbial activity, nitrogen availability, SOC, and aboveground biomass in the future. Managers should consider this information to reorient current crop residue management to achieve the objectives and the sustainability of forest management in Mexican temperate forests.

scholarly journals Disentangling residence time and temperature sensitivity of microbial decomposition in a global soil carbon model

2014 ◽  
Vol 11 (23) ◽  
pp. 6999-7008 ◽  
Author(s):  
J.-F. Exbrayat ◽  
A. J. Pitman ◽  
G. Abramowitz
Keyword(s):  
Soil Carbon ◽  
Residence Time ◽  
Carbon Balance ◽  
Carbon Stocks ◽  
Historical Period ◽  
Microbial Decomposition ◽  
Total Soil ◽  
Industrial Soil ◽  
The Future ◽  
The Impact

Abstract. Recent studies have identified the first-order representation of microbial decomposition as a major source of uncertainty in simulations and projections of the terrestrial carbon balance. Here, we use a reduced complexity model representative of current state-of-the-art models of soil organic carbon decomposition. We undertake a systematic sensitivity analysis to disentangle the effect of the time-invariant baseline residence time (k) and the sensitivity of microbial decomposition to temperature (Q10) on soil carbon dynamics at regional and global scales. Our simulations produce a range in total soil carbon at equilibrium of ~ 592 to 2745 Pg C, which is similar to the ~ 561 to 2938 Pg C range in pre-industrial soil carbon in models used in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). This range depends primarily on the value of k, although the impact of Q10 is not trivial at regional scales. As climate changes through the historical period, and into the future, k is primarily responsible for the magnitude of the response in soil carbon, whereas Q10 determines whether the soil remains a sink, or becomes a source in the future mostly by its effect on mid-latitude carbon balance. If we restrict our simulations to those simulating total soil carbon stocks consistent with observations of current stocks, the projected range in total soil carbon change is reduced by 42% for the historical simulations and 45% for the future projections. However, while this observation-based selection dismisses outliers, it does not increase confidence in the future sign of the soil carbon feedback. We conclude that despite this result, future estimates of soil carbon and how soil carbon responds to climate change should be more constrained by available data sets of carbon stocks.

scholarly journals Disentangling residence time and temperature sensitivity of microbial decomposition in a global soil carbon model

2014 ◽  
Vol 11 (3) ◽  
pp. 4995-5021 ◽  
Author(s):  
J.-F. Exbrayat ◽  
A. J. Pitman ◽  
G. Abramowitz
Keyword(s):  
Soil Carbon ◽  
Residence Time ◽  
Carbon Balance ◽  
Coupled Model ◽  
Historical Period ◽  
Microbial Decomposition ◽  
Total Soil ◽  
Industrial Soil ◽  
The Future ◽  
The Impact

Abstract. Recent studies have identified the first-order parameterization of microbial decomposition as a major source of uncertainty in simulations and projections of the terrestrial carbon balance. Here, we use a reduced complexity model representative of the current state-of-the-art parameterization of soil organic carbon decomposition. We undertake a systematic sensitivity analysis to disentangle the effect of the time-invariant baseline residence time (k) and the sensitvity of microbial decomposition to temperature (Q10) on soil carbon dynamics at regional and global scales. Our simulations produce a range in total soil carbon at equilibrium of ~ 592 to 2745 Pg C which is similar to the ~ 561 to 2938 Pg C range in pre-industrial soil carbon in models used in the fifth phase of the Coupled Model Intercomparison Project. This range depends primarily on the value of k, although the impact of Q10 is not trivial at regional scales. As climate changes through the historical period, and into the future, k is primarily responsible for the magnitude of the response in soil carbon, whereas Q10 determines whether the soil remains a sink, or becomes a source in the future mostly by its effect on mid-latitudes carbon balance. If we restrict our simulations to those simulating total soil carbon stocks consistent with observations of current stocks, the projected range in total soil carbon change is reduced by 42% for the historical simulations and 45% for the future projections. However, while this observation-based selection dismisses outliers it does not increase confidence in the future sign of the soil carbon feedback. We conclude that despite this result, future estimates of soil carbon, and how soil carbon responds to climate change should be constrained by available observational data sets.

Pengaruh Budaya Terhadap Akuntansi, Auditing Dan Praktik Akuntansi Internasional

2016 ◽  
Vol 3 (1) ◽  
pp. 78-95
Author(s):  
Priyastiwi Priyastiwi
Keyword(s):  
Cultural Values ◽  
Leadership Style ◽  
Financial Reporting ◽  
National Level ◽  
Deep Understanding ◽  
Cultural Dimensions ◽  
Financial Disclosure ◽  
Cross Cultural Differences ◽  
The Future ◽  
The Impact

The purpose of this article is to provide the basic model of Hofstede and Grays’ cultural values that relates the Hofstede’s cultural dimensions and Gray‘s accounting value. This article reviews some studies that prove the model and develop the research in the future. There are some evidences that link the Hofstede’s cultural values studies with the auditor’s judgment and decisions by developing a framework that categorizes the auditor’s judgments and decisions are most likely influenced by cross-cultural differences. The categories include risk assessment, risk decisions and ethical judgments. Understanding the impact of cultural factors on the practice of accounting and financial disclosure is important to achieve the harmonization of international accounting. Deep understanding about how the local values may affect the accounting practices and their impacts on the financial disclosure are important to ensure the international comparability of financial reporting. Gray’s framework (1988) expects how the culture may affect accounting practices at the national level. One area of the future studies will examine the impact of cultural dimensions to the values of accounting, auditing and decision making. Key word : Motivation, leadership style, job satisfaction, performance

A Study on the Impact of Family-friendly Certification on Financial Performance of SMEs: Focusing on the Manufacturing Industry

2019 ◽  
Vol 118 (2) ◽  
pp. 7-12
Author(s):  
Ok-Hee Park ◽  
Kwan-sik Na ◽  
Seok-Kee Lee
Keyword(s):  
Financial Performance ◽  
Family Life ◽  
Manufacturing Industry ◽  
Work And Family ◽  
Family Friendly ◽  
The Future ◽  
The Impact

Background/Objectives: The purpose of the paper is to examine how family-friendly certificates introduced to pursue the compatibility of work and family life affect the financial performance of small and medium-sized manufacturers, and to provide useful information to companies considering the introduction of this system in the future.

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