scholarly journals Those who can don’t want to, and those who want to can’t: eco-evolutionary constraints to decomposition explain soil carbon persistence

2021 ◽  
Author(s):  
Mark Bonner ◽  
Oskar Franklin ◽  
Shun Hasegawa ◽  
Torgny Näsholm
Keyword(s):  
Mathematical Model ◽  
Organic Matter ◽  
Land Management ◽  
Nitrogen Addition ◽  
Evolutionary Constraints ◽  
Mycelial Fungi ◽  
Proof Of Concept ◽  
Typical Composition ◽  
Physical Limitations ◽  
Geometrically Constrained

Reliable manipulation of soil organic matter (SOM) – a necessity for optimal land management – is constrained by our limited mechanistic understanding of SOM formation. Here we add to existing frameworks a novel mechanistic element that may underpin SOM dynamics, based on evolutionary-ecological rather than chemical or physical limitations to decomposition. We argue that decomposition of some substrates may be ecologically constrained in mycelial fungi, evolutionarily constrained in co-operating bacteria, and geometrically constrained in unicellular microbes. We describe and test a mathematical model based on our framework, providing a proof-of-concept that substrate can plausibly be spared decomposition and accumulate even when it is physically and chemically accessible. Our framework can explain a variety of SOM dynamics, including priming and the suppression of decomposition by nitrogen addition, as well as the typical composition of SOM. An augmented mechanistic framework for understanding SOM dynamics can help guide targeted empirical study, which in turn can contribute to more optimised land management.

Modelling of experiments with colloidal organic matter in biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 479-486 ◽  
Author(s):  
T. A. Larsen ◽  
P. Harremoës
Keyword(s):  
Mathematical Model ◽  
Organic Matter ◽  
Bulk Liquid ◽  
Native Starch ◽  
Trickling Filters ◽  
Biofilm Reactors ◽  
Removal Capacity

A mathematical model for the degradation of colloidal organic matter in biofilm reactors has been developed. Contradictory to existing theories, the model includes bulk liquid hydrolysis as the first important step in the degradation sequence. This leads to unexpected effects of different reactor configurations. The model was successfully verified with native starch as a model substrate. Observed differences in colloid removal capacity between trickling filters and RBC-reactors are well explained by the model.

scholarly journals Land Management Impacts on Soil Water Erosion and Loss of Nutrients

Proceedings ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 35 ◽  
Author(s):  
Telak ◽  
Bogunovic ◽  
Rodrigo-Comino
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Land Management ◽  
Sediment Yield ◽  
Management Practices ◽  
Overland Flow ◽  
Organic Matter Content ◽  
Nutrient Loss ◽  
Plant Residues ◽  
Significant Difference

Humans are the driving factor of soil erosion and degradation. Therefore, sustainable land management practices should be developed and applied. The aim of this study was to determine land management impacts on soil properties, soil loss and nutrient loss in 3 different treatments; grass-covered vineyard (GCV), tilled vineyard (TV), and tilled hazelnut orchard (HO). The study area is located in Orahovica, Croatia (45°31′ N, 17°51′ E; elevation 230 m) on ~7° slope. The soil under the study area was classified as a Stagnosol. 8 rainfall simulations (58 mm h−1, during 30 min, over 0.785 m2 plots) were performed at each treatment where the next data were noted: ponding time, runoff time, and collection of overland flow. Soil samples were taken for determination of mean weight diameter (MWD), water stable aggregates (WSA), P2O5 content, and organic matter content. Analyses of sediment revealed concentrations of P2O5 and N. All three treatments had significantly different values of MWD (GCV 3.30 mm; TV 2.94 mm; HO 2.16 mm), while WSA and organic matter significantly differs between GCV and HO. The infiltration rate showed no significant difference between treatments. Sediment yield was significantly the highest at the TV (21.01 g kg−1 runoff), while no significant difference was noted between GCV (2.91) and HO (6.59). Sediments of GCV treatment showed higher concentrations of P2O5 and N, compared to TV and HO. Nutrients loss was highest in the TV (450.3 g P2O5 ha−1; 1891.7 g N ha−1) as a result of highest sediment yield, despite the fact GCV had the highest nutrients concentrations. Results indicate that land management (and/or tillage) affects soil properties and their stability. Even tough HO was tilled and had the lowest values of organic matter, WSA, and MWD, measurements were performed immediately after tillage where the plant residues reduced potential erodibility of the soil. Such results reveal that tillage should be avoided in vineyard and hazelnut production in order to prevent soil and nutrient losses.

Nitrogen addition affects chemical compositions of plant tissues, litter and soil organic matter

Ecology ◽  
2016 ◽  
Vol 97 (7) ◽  
pp. 1796-1806 ◽  
Author(s):  
Jun Liu ◽  
Nana Wu ◽  
Hui Wang ◽  
Jianfei Sun ◽  
Bo Peng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nitrogen Addition ◽  
Plant Tissues ◽  
Chemical Compositions

Modeling of anaerobic treatment of wastewater in ponds

2007 ◽  
Vol 55 (11) ◽  
pp. 47-56 ◽  
Author(s):  
B.K. Rajbhandari ◽  
A.P. Annachhatre ◽  
J.L. Vasel
Keyword(s):  
Mathematical Model ◽  
Organic Matter ◽  
Biological Activity ◽  
Reduction Process ◽  
Anaerobic Treatment ◽  
Sediment Layer ◽  
Digestion Process ◽  
Sulphate Removal ◽  
Soluble Components ◽  
Good Agreement

A mathematical model to simulate the performance of anaerobic ponds was developed incorporating both settling of particulate components and the biological anaerobic digestion process. The biological activity includes solubilization of particulate organic matter; methanogenesis and the sulphate reduction process. The model considers that an anaerobic pond comprises a series of equal size columns. Each column has three compartments viz. liquid layer, active sediment layer and inert sediment layer. The existence of organic matter and sulphate removal mechanisms both in the bulk as well as sediment layer of the ponds and the exchange of the soluble components between the layers has been included in the model. The model was transferred to a computer program using VisSim Basic software. The model was verified by comparing simulated results with full-scale as well as with laboratory-scale anaerobic pond performance data. A good agreement between the simulated and the observed pond performance was achieved.

Effect of nitrogen addition on Miscanthus  × giganteus yield, nitrogen losses, and soil organic matter across five sites

GCB Bioenergy ◽  
2014 ◽  
Vol 7 (6) ◽  
pp. 1222-1231 ◽  
Author(s):  
Morgan P. Davis ◽  
Mark B. David ◽  
Thomas B. Voigt ◽  
Corey A. Mitchell
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nitrogen Addition ◽  
Nitrogen Losses ◽  
Miscanthus Giganteus

scholarly journals Combined effects of nitrogen addition and organic matter manipulation on soil respiration in a Chinese pine forest

2016 ◽  
Vol 23 (22) ◽  
pp. 22701-22710 ◽  
Author(s):  
Jinsong Wang ◽  
L. Wu ◽  
Chunyu Zhang ◽  
Xiuhai Zhao ◽  
Wensheng Bu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Respiration ◽  
Nitrogen Addition ◽  
Pine Forest ◽  
Combined Effects ◽  
Chinese Pine ◽  
Chinese Pine Forest

scholarly journals Influenza emergence in the face of evolutionary constraints

2011 ◽  
Vol 279 (1729) ◽  
pp. 645-652 ◽  
Author(s):  
Adam Kucharski ◽  
Julia R. Gog
Keyword(s):  
Mathematical Model ◽  
Fitness Cost ◽  
Antigenic Drift ◽  
Evolutionary Constraints ◽  
The Face ◽  
Antigenic Evolution ◽  
Cross Immunity ◽  
Rate Of Emergence

Different influenza subtypes can evolve at very different rates, but the causes are not well understood. In this paper, we explore whether differences in transmissibility between subtypes can play a role if there are fitness constraints on antigenic evolution. We investigate the problem using a mathematical model that separates the interaction of strains through cross-immunity from the process of emergence for new antigenic variants. Evolutionary constraints are also included with antigenic mutation incurring a fitness cost. We show that the transmissibility of a strain can become disproportionately important in dictating the rate of antigenic drift: strains that spread only slightly more easily can have a much higher rate of emergence. Further, we see that the effect continues when vaccination is considered; a small increase in the rate of transmission can make it much harder to control the frequency at which new strains emerge. Our results not only highlight the importance of considering both transmission and fitness constraints when modelling influenza evolution, but may also help in understanding the differences between the emergence of H1N1 and H3N2 subtypes.

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