Mountain lakes increase organic matter decomposition rates in streams

2010 ◽  
Vol 29 (2) ◽  
pp. 521-529 ◽  
Author(s):  
Keli J. Goodman ◽  
Michelle A. Baker ◽  
Wayne A. Wurtsbaugh
Keyword(s):  
Organic Matter ◽  
Mountain Lakes ◽  
Organic Matter Decomposition ◽  
Decomposition Rates

scholarly journals Sensitivity analysis of six soil organic matter models applied to the decomposition of animal manures and crop residues

2016 ◽  
Vol 11 ◽  
Author(s):  
Daniele Cavalli ◽  
Pietro Marino Gallina ◽  
Luca Bechini
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Organic Matter Decomposition ◽  
Model Parameters ◽  
Monod Kinetics ◽  
Decomposition Rates ◽  
Mineral N ◽  
First Order ◽  
Inhibition Hypothesis ◽  
C Decomposition

Two features distinguishing soil organic matter simulation models are the type of kinetics used to calculate pool decomposition rates, and the algorithm used to handle the effects of N shortage on C decomposition. Compared to widely used first-order kinetics, Monod kinetics more realistically represent organic matter decomposition, because they relate decomposition to both substrate and decomposer size. Most models impose a fixed C to N ratio for microbial biomass. When N required by microbial biomass to decompose a given amount of substrate- C is larger than soil available N, carbon decomposition rates are limited proportionally to N deficit (N inhibition hypothesis). Alternatively, C-overflow was proposed as a way of getting rid of excess C, by allocating it to a storage pool of polysaccharides. We built six models to compare the combinations of three decomposition kinetics (first-order, Monod, and reverse Monod), and two ways to simulate the effect of N shortage on C decomposition (N inhibition and C-overflow). We conducted sensitivity analysis to identify model parameters that mostly affected CO<sub>2</sub> emissions and soil mineral N during a simulated 189-day laboratory incubation assuming constant water content and temperature. We evaluated model outputs sensitivity at different stages of organic matter decomposition in a soil amended with three inputs of increasing C to N ratio: liquid manure, solid manure, and low-N crop residue. Only few model parameters and their interactions were responsible for consistent variations of CO<sub>2</sub> and soil mineral N. These parameters were mostly related to microbial biomass and to the partitioning of applied C among input pools, as well as their decomposition constants. In addition, in models with Monod kinetics, CO<sub>2</sub> was also sensitive to a variation of the halfsaturation constants. C-overflow enhanced pool decomposition compared to N inhibition hypothesis when N shortage occurred. Accumulated C in the polysaccharides pool decomposed slowly; therefore model outputs were not sensitive to a variation of its decay constant. Six-month organic matter decomposition was generally higher for models implementing classical Monod kinetics, followed by models with first-order and reverse Monod kinetics, due to the effect of soil microbial biomass growth on decomposition rates. Moreover, models implementing Monod kinetics predicted positive priming effects of native organic matter after soil amendment, according to co-metabolism theory. Thus, priming was proportional to the increase of the microbial biomass and in turn to the decomposability of applied organic matter. We conclude that model calibration should focus only on the few important parameters.

scholarly journals Models of soil organic matter decomposition: the SOILR package, version 1.0

2012 ◽  
Vol 5 (2) ◽  
pp. 993-1039 ◽  
Author(s):  
C. A. Sierra ◽  
M. Müller ◽  
S. E. Trumbore
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Matter Decomposition ◽  
Important Process ◽  
Decomposition Rates ◽  
Modeling Framework ◽  
Soil Organic Matter Decomposition ◽  
The Earth ◽  
Decomposition Models ◽  
Model Structures

Abstract. Organic matter decomposition is a very important process within the Earth System because it controls the rates of mineralization of carbon and other biogeochemical elements, determining their flux to the atmosphere and the hydrosphere. SOILR is a modeling framework that contains a library of functions and tools for modeling soil organic matter decomposition under the R environment for computing. It implements a variety of model structures and tools to represent carbon storage and release from soil organic matter. In SOILR organic matter decomposition is represented as a linear system of ordinary differential equations that generalizes the structure of most compartment-based decomposition models. A variety of functions is also available to represent environmental effects on decomposition rates. This document presents the conceptual basis for the functions implemented in the package. It is complementary to the help pages released with the software.

scholarly journals Models of soil organic matter decomposition: the SoilR package, version 1.0

2012 ◽  
Vol 5 (4) ◽  
pp. 1045-1060 ◽  
Author(s):  
C. A. Sierra ◽  
M. Müller ◽  
S. E. Trumbore
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Matter Decomposition ◽  
Important Process ◽  
Decomposition Rates ◽  
Modeling Framework ◽  
Soil Organic Matter Decomposition ◽  
The Earth ◽  
Decomposition Models ◽  
Model Structures

Abstract. Soil organic matter decomposition is a very important process within the Earth system because it controls the rates of mineralization of carbon and other biogeochemical elements, determining their flux to the atmosphere and the hydrosphere. SoilR is a modeling framework that contains a library of functions and tools for modeling soil organic matter decomposition under the R environment for computing. It implements a variety of model structures and tools to represent carbon storage and release from soil organic matter. In SoilR, organic matter decomposition is represented as a linear system of ordinary differential equations that generalizes the structure of most compartment-based decomposition models. A variety of functions is also available to represent environmental effects on decomposition rates. This document presents the conceptual basis for the functions implemented in the package. It is complementary to the help pages released with the software.

Temperature and soil organic matter decomposition rates - synthesis of current knowledge and a way forward

2011 ◽  
Vol 17 (11) ◽  
pp. 3392-3404 ◽  
Author(s):  
Richard T. Conant ◽  
Michael G. Ryan ◽  
Göran I. Ågren ◽  
Hannah E. Birge ◽  
Eric A. Davidson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Current Knowledge ◽  
Organic Matter Decomposition ◽  
Decomposition Rates ◽  
Soil Organic Matter Decomposition

Influence of carbon and nitrogen on cellulose and lignin degradation in forest soils

1995 ◽  
Vol 25 (8) ◽  
pp. 1231-1236 ◽  
Author(s):  
James A. Entry ◽  
Carole B. Backman
Keyword(s):  
Organic Matter ◽  
Soil Type ◽  
Fungal Biomass ◽  
Lignin Degradation ◽  
Cellulose Degradation ◽  
Bacterial Biomass ◽  
Terrestrial Ecosystems ◽  
Organic Matter Decomposition ◽  
Decomposition Rates ◽  
C And N

The concentration of lignin in plant tissue is a major factor controlling organic matter decomposition rates in terrestrial ecosystems. Microcosms were used to determine the influence of C and N additions on active bacterial and active fungal biomass, cellulose degradation, and lignin degradation at 4, 8, and 12 weeks in soils from the Tuskeege National Forest in southern Alabama. Active bacterial and active fungal biomass was determined by direct microscopy; cellulose and lignin degradation were measured radiometrically. The experimental design was a 33 latin square. Treatments were as follows: soil type, soil C (soils amended with the equivalent of 0, 400, or 800 kg C•ha−1 as cellulose), and soil N (soils amended with the equivalent of 0, 250, or 500 kg N•ha−1 as NH4NO3). Active bacterial biomass, active fungal biomass, and cellulose and lignin degradation did not differ with soil type. Active bacterial biomass was not affected by N or C additions. As C and N concentrations increased, active fungal biomass as well as cellulose and lignin degradation increased. The concentration of C and N (together) in the soil correlated with both cellulose and lignin degradation (r2 = 0.76, p < 0.001; r2 = 0.44, p < 0.001, respectively). Active fungal biomass correlated curvilinearly with both cellulose and lignin degradation (r2 = 0.38, p < 0.001; r2 = 0.33, p < 0.001, respectively). The lignin:N ratio is often used to predict organic matter decomposition rates in terrestrial ecosystems. These results lead us to conclude that a cellulose:lignin:N ratio may be a more accurate predictor of organic matter decomposition rates than C:N ratio or lignin:N ratios.

ORGANIC MATTER DECOMPOSITION RATES IN ARCTIC SOILS

Soil Science ◽  
1959 ◽  
Vol 88 (6) ◽  
pp. 305-312 ◽  
Author(s):  
L. A. DOUGLAS ◽  
J. C. F. TEDROW
Keyword(s):  
Organic Matter ◽  
Organic Matter Decomposition ◽  
Decomposition Rates ◽  
Arctic Soils
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