10-Year fertilization alters soil C dynamics as indicated by amino sugar differentiation and oxidizable organic C pools in a greenhouse vegetable field of Tianjin, China

Loss of labile carbon (C) fractions yields information about the impact of land-use changes on sources of C inputs, pathways of C losses and mechanisms of soil C sequestration. This study dealt with the total organic C (TOC) and labile C pools in 40 surface soil samples (0–15 cm) collected from four land-use practices: uncultivated sites and rice–wheat, maize–wheat and sugarcane agro-ecosystems. Uncultivated soils had a higher total C pool than croplands. The soil inorganic C concentrations were in the range of 0.7–1.4 g kg–1 under different land-use practices. Strong correlations were found between TOC and all organic C pools, except water-extractable organic C and mineralisable C. The sensitivity index indicated that soil organic C pools were susceptible to changes in land-use practices. Discriminant function analysis showed that the nine soil variables could distinguish the maize–wheat and rice–wheat systems from uncultivated and sugarcane systems. Finally, we recommend crop rotation practices whereby planting sugarcane replenishes TOC content in soils.

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Spatial variability in terrestrial and aquatic carbon stocks and fluxes in boreal forested catchments

10.5194/egusphere-egu2020-5558 ◽

2020 ◽

Author(s):

Nora Casson ◽

Adrienne Ducharme ◽

Geethani Amarawansha ◽

Geoff Gunn ◽

Scott Higgins ◽

...

Keyword(s):

Spatial Variability ◽

Soil Depth ◽

Organic C ◽

Soil C ◽

C Pools ◽

Sampling Campaign ◽

C Stocks ◽

Doc Export ◽

Rain Events ◽

C Pools And Fluxes

<p>Canada&#8217;s boreal zone is a complex mosaic of forests, wetlands, streams and lakes.&#160; The pool of carbon (C) stored in each of these ecosystem components is vast, and significant to the global C balance.&#160; However, C pools and fluxes are heterogeneous in time and space, which contributes to uncertainty in predicting how a changing climate will affect the fate of C in these sensitive ecosystems. The objective of this study was to investigate factors controlling spatial variability in soil C stocks and stream C export and assess the sensitivity of these stocks and fluxes to climatic factors. We conducted a detailed examination of soil C stocks and stream dissolved organic C (DOC) export from a 320 ha boreal forested catchment located in northwestern Ontario, Canada. High-frequency stream chemistry and discharge samples were collected from three inflow streams during snowmelt and rain events from 2016-2017. An intensive soil C sampling campaign resulting in 47 surface (0 &#8211; 30 cm) samples were collected during the summer of 2019. Stream hysteresis analysis revealed marked differences in flowpaths among sub-catchments during snowmelt and rain events. In the wetland-dominated catchment, near-stream sources contributed most of the DOC export during both rainstorms and snowmelt events, but in upland-dominated catchments, the sources of DOC depended on antecedent moisture conditions. Rainstorms in these catchments following prolonged droughts resulted in DOC flushing from distal regions of the catchment. Soil C stocks were also highly spatially variable, with much of the variability being explained by local-scale factors (e.g. gravel content, soil depth, distance to the nearest ridge). Taken together, these two findings emphasize the need to consider sub-catchment scale variability when calculating C pools and fluxes in boreal catchments. This is also important when predicting how C dynamics will shift in the future as a result of shorter winters, longer droughts and more intense rainstorms.</p>

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Soil management effects on organic carbon in isolated fractions of a Gray Luvisol

Canadian Journal of Soil Science ◽

10.4141/s05-037 ◽

2006 ◽

Vol 86 (1) ◽

pp. 141-151 ◽

Cited By ~ 12

Author(s):

A. F. Plante ◽

C. E. Stewart ◽

R. T. Conant ◽

K. Paustian ◽

J. Six

Keyword(s):

Organic Matter ◽

Crop Production ◽

N Fertilization ◽

Residue Management ◽

Soil Organic C ◽

Organic C ◽

Straw Management ◽

Soil C ◽

C Pools

Agricultural management affects soil organic matter, which is important for sustainable crop production and as a greenhouse gas sink. Our objective was to determine how tillage, residue management and N fertilization affect organic C in unprotected, and physically, chemically and biochemically protected soil C pools. Samples from Breton, Alberta were fractionated and analysed for organic C content. As in previous reports, N fertilization had a positive effect, tillage had a minimal effect, and straw management had no effect on whole-soil organic C. Tillage and straw management did not alter organic C concentrations in the isolated C pools, while N fertilization increased C concentrations in all pools. Compared with a woodlot soil, the cultivated plots had lower total organic C, and the C was redistributed among isolated pools. The free light fraction and coarse particulate organic matter responded positively to C inputs, suggesting that much of the accumulated organic C occurred in an unprotected pool. The easily dispersed silt-sized fraction was the mineral-associated pool most responsive to changes in C inputs, whereas the microaggregate-derived silt-sized fraction best preserved C upon cultivation. These findings suggest that the silt-sized fraction is important for the long-term stabilization of organic matter through both physical occlusion in microaggregates and chemical protection by mineral association. Key words: Soil organic C, tillage, residue management, N fertilization, silt, clay

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Changes in organic C stability within soil aggregates under different fertilization patterns in a greenhouse vegetable field

Journal of Integrative Agriculture ◽

10.1016/s2095-3119(21)63646-8 ◽

2021 ◽

Vol 20 (10) ◽

pp. 2758-2771

Author(s):

Hao-an LUAN ◽

Shuo YUAN ◽

Wei GAO ◽

Ji-wei TANG ◽

Ruo-nan LI ◽

...

Keyword(s):

Soil Aggregates ◽

Organic C ◽

Vegetable Field ◽

Greenhouse Vegetable

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Heterogeneity of soil carbon pools and fluxes in a channelized and a restored floodplain section (Thur River, Switzerland)

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-8-1059-2011 ◽

2011 ◽

Vol 8 (1) ◽

pp. 1059-1091 ◽

Cited By ~ 14

Author(s):

E. Samaritani ◽

J. Shrestha ◽

B. Fournier ◽

E. Frossard ◽

F. Gillet ◽

...

Keyword(s):

Soil Respiration ◽

Spatial Heterogeneity ◽

Soil Properties ◽

Ecosystem Functions ◽

Flood Disturbance ◽

Organic C ◽

C Pools ◽

C Dynamics ◽

Wide Range ◽

Gravel Bars

Abstract. Due to their spatial complexity and dynamic nature, floodplains provide a wide range of ecosystem functions. However, because of flow regulation, many riverine floodplains have lost their characteristic heterogeneity. Restoration of floodplain habitats and the rehabilitation of key ecosystem functions has therefore become a major goal of environmental policy. Many important ecosystem functions are linked to organic carbon (C) dynamics in riparian soils. The fundamental understanding of the factors that drive the processes involved in C cycling in heterogeneous and dynamic systems such as floodplains is however only fragmentary. We quantified soil organic C pools (microbial C and water extractable organic C) and fluxes (soil respiration and net methane production) in functional process zones of adjacent channelized and widened sections of the Thur River, NE Switzerland, on a seasonal basis. The objective was to assess how spatial heterogeneity and temporal variability of these pools and fluxes relate to physicochemical soil properties on one hand, and to soil environmental conditions and flood disturbance on the other hand. Overall, factors related to seasonality and flooding (temperature, water content, organic matter input) affected soil C dynamics more than soil properties did. Coarse-textured soils on gravel bars in the restored section were characterized by low base-levels of organic C pools due to low TOC contents. However, frequent disturbance by flood pulses led to high heterogeneity with temporarily and locally increased pools and soil respiration. By contrast, in stable riparian forests, the finer texture of the soils and corresponding higher TOC contents and water retention capacity led to high base-levels of C pools. Spatial heterogeneity was low, but major floods and seasonal differences in temperature had additional impacts on both pools and fluxes. Soil properties and base levels of C pools in the dam foreland of the channelized section were similar to the gravel bars of the restored section. By contrast, spatial heterogeneity, seasonal effects and flood disturbance were similar to the forests, except for indications of high CH4 production that are explained by long travel times of infiltrating water favouring reducing conditions. Overall, the restored section exhibited both a larger range and a higher heterogeneity of organic C pools and fluxes as well as a higher plant biodiversity than the channelized section. This suggests that restoration has indeed led to an increase in functional diversity.

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Carbon input control over soil organic matter dynamics in a temperate grassland exposed to elevated CO<sub>2</sub> and warming

Biogeosciences Discussions ◽

10.5194/bgd-7-1575-2010 ◽

2010 ◽

Vol 7 (2) ◽

pp. 1575-1602 ◽

Cited By ~ 5

Author(s):

Y. Carrillo ◽

E. Pendall ◽

F. A. Dijkstra ◽

J. A. Morgan ◽

J. M. Newcomb

Keyword(s):

Climate Change ◽

Organic Matter ◽

Elevated Co2 ◽

Combined Effects ◽

Organic C ◽

Soil C ◽

C Storage ◽

C Pools ◽

Labile C ◽

Semi Arid

Abstract. Elevated CO2 generally increases soil C pools. However, greater available C concentrations can potentially stimulate soil organic matter (SOM) decomposition. The effects of climate warming on C storage can also be positive or negative. There is a high degree of uncertainty on the combined effects of climate warming and atmospheric CO2 increase on SOM dynamics and its potential feedbacks to climate change. Semi-arid systems are predicted to show strong ecosystem responses to both factors. Global change factors can have contrasting effects for different SOM pools, thus, to understand the mechanisms underlying the combined effects of multiple factors on soil C storage, effects on individual C pools and their kinetics should be evaluated. We assessed SOM dynamics by conducting long-term laboratory incubations of soils from PHACE (Prairie Heating and CO2 Enrichment experiment), an elevated CO2 and warming field experiment in semi-arid, native northern mixed grass prairie, Wyoming, USA. We measured total C mineralization and estimated the size of the labile pool and the decomposition rates of the labile and resistant SOM pools. To examine the role of plant inputs on SOM dynamics we measured aboveground biomass, root biomass, and soil dissolved organic C (DOC). Greater aboveground productivity under elevated CO2 translated into enlarged pools of readily available C (measured as total mineralized C, labile C pool and DOC). The effects of warming on the labile C only occurred in the first year of warming suggesting a transient effect of the microbial response to increased temperature. Experimental climate change affected the intrinsic decomposability of both the labile and resistant C pools. Positive relationships of the rate of decomposition of the resistant C with aboveground and belowground biomass and dissolved organic C suggested that plant inputs mediated the response by enhancing the degradability of the resistant C. Our results contribute to a growing body of literature suggesting that priming is a ubiquitous phenomenon that should be included in C cycle models.

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Energetic return on investment determines overall soil microbial activity.

10.21203/rs.3.rs-388050/v1 ◽

2021 ◽

Author(s):

Louis Dufour ◽

Anke Herrmann ◽

Julie Leloup ◽

Cédric Przybylski ◽

Ludovic Foti ◽

...

Keyword(s):

Microbial Communities ◽

Return On Investment ◽

Metabolic Response ◽

Soil Microbial Activity ◽

Organic C ◽

Soil C ◽

Soil Microbial ◽

C Dynamics ◽

C Cycle ◽

Energetic Analysis

Abstract Microbial communities are a critical component of the soil carbon (C) cycle, as they are responsible for the decomposition of both organic inputs from plants and of soil organic C. However, there is still no consensus about how to explicitly represent their role in terrestrial C cycling. We suggest that a full understanding of microbial communities’ involvement in soil C dynamics can only be attained when the interaction between the properties of both available organic C and microbial communities are accounted for. Here, we show that the potential energetic return on investment, derived from an energetic analysis of available organic C, is strongly related to the overall metabolic response of microbial decomposers. We further show that microbial communities do not all obtain the same energetic return on investment when metabolising the same organic C, suggesting that the response also depends on the intrinsic properties of the microbial communities.

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Carbon pool trends and dynamics within a subtropical peatland during long-term restoration

10.1101/196907 ◽

2017 ◽

Author(s):

Paul Julian ◽

Stefan Gerber ◽

Alan L. Wright ◽

Binhe Gu ◽

Todd Z. Osborne

Keyword(s):

Water Conservation ◽

Temporal Trends ◽

Florida Everglades ◽

Nutrient Inputs ◽

Conservation Area ◽

Organic C ◽

C Pools ◽

C Dynamics ◽

Hydrologic Condition

AbstractBackgroundThe Florida Everglades has undergone significant ecological change spanning the continuum of disturbance to restoration. While the restoration effort is not complete and the ecosystem continues to experience short duration perturbations, a better understanding of long-term C dynamics of the Everglades is needed to facilitate new restoration efforts. This study evaluated temporal trends of different aquatic carbon (C) pools of the northern Everglades Protection Area over a 20-year period to gauge historic C cycling patterns. Dissolved inorganic C (DIC), dissolved organic C (DOC), particulate organic C (POC), and surface water carbon dioxide (pCO2(aq)) were investigated between May 1, 1994 and April 30, 2015.ResultsAnnual mean concentrations of DIC, DOC, POC, and pCO2(aq)significantly decreased through time or remained constant across the Water Conservation Areas (WCAs). Overall, the magnitude of the different C pools in the water column significantly differed between regions. Outgassing of CO2was dynamic across the Everglades ranging from 420 to 2001 kg CO2yr-1. Overall the historic trend in CO2flux from the marsh declined across our study area while pCO2(aq)largely remained somewhat constant with the exception of Water Conservation Area 2 which experienced significant declines in pCO2(aq). Particulate OC concentrations were consistent between WCAs, but a significantly decreasing trend in annual POC concentrations were observed.ConclusionsHydrologic condition and nutrient inputs significantly influenced the balance, speciation, and flux of C pools across WCAs suggesting a subsidy-stress response in C dynamics relative to landscape scale responses in nutrient availability. The interplay between nutrient inputs and hydrologic condition exert a driving force on the balance between DIC and DOC production via the metabolism of organic matter which forms the base of the aquatic foodweb. Along the restoration trajectory as water quality and hydrology continues to improve it is expected that C pools will respond accordingly.

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Assessing a new soil carbon model to simulate the effect of temperature increase on the soil carbon cycle in three eastern Canadian forest types characterized by different climatic conditions

Canadian Journal of Soil Science ◽

10.4141/s05-080 ◽

2006 ◽

Vol 86 (Special Issue) ◽

pp. 187-202 ◽

Cited By ~ 5

Author(s):

Guy R. Larocque ◽

Robert Boutin, David Paré ◽

Gilles Robitaille ◽

Valérie Lacerte

Keyword(s):

Soil Respiration ◽

Soil Carbon ◽

Abies Balsamea ◽

Litter Production ◽

Forest Types ◽

Organic C ◽

Soil C ◽

C Pools ◽

C Cycle ◽

Process Based Models

The predictive capacity of process-based models on the carbon (C) cycle in forest ecosystems is limited by the lack of knowledge on the processes involved. Thus, a better understanding of the C cycle may contribute to the development of process-based models that better represent the processes in C cycle models. A new soil C model was developed to predict the effect of an increase in the temperature regime on soil C dynamics and pools in sugar maple (Acer saccharum Marsh.), balsam fir [Abies balsamea (L.) Mill.] and black spruce [Picea mariana (Mill.) B.S.P.] forest types in Eastern Canada. Background information to calibrate the model originated from the experimental sites of the ECOLEAP project as well as from a companion study on laboratory soil incubation. Different types of litter were considered in the model: foliage, twigs, understory species, other fine detritus and fine roots. A cohort approach was used to model litter mineralization over time. The soil organic C in the organic (F and H) and mineral layers (0–20 cm) was partitioned into active, slow and passive pools and the rates of C transfer among the different pools and the amount of CO2 respired were modelled. For each forest type, there was a synchrony of response of the C pools to soil temperature variation. The results of the simulations indicated that steady state conditions were obtained under current temperature conditions. When mean annual soil temperatures were gradually increased, the litter and active and slow C pools decreased substantially, but the passive pools were minimally affected. The increase in soil respiration resulting from a gradual increase in temperature was not pronounced in comparison to changes in mineralization rates. An increase in litter production during the same period could contribute to reducing net C losses. Key words: Soil organic matter, litter, soil respiration, climate change

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Heterogeneity of soil carbon pools and fluxes in a channelized and a restored floodplain section (Thur River, Switzerland)

Hydrology and Earth System Sciences ◽

10.5194/hess-15-1757-2011 ◽

2011 ◽

Vol 15 (6) ◽

pp. 1757-1769 ◽

Cited By ~ 37

Author(s):

E. Samaritani ◽

J. Shrestha ◽

B. Fournier ◽

E. Frossard ◽

F. Gillet ◽

...

Keyword(s):

Soil Respiration ◽

Spatial Heterogeneity ◽

Soil Properties ◽

Ecosystem Functions ◽

Flood Disturbance ◽

Organic C ◽

C Pools ◽

C Dynamics ◽

Wide Range ◽

Gravel Bars

Abstract. Due to their spatial complexity and dynamic nature, floodplains provide a wide range of ecosystem functions. However, because of flow regulation, many riverine floodplains have lost their characteristic heterogeneity. Restoration of floodplain habitats and the rehabilitation of key ecosystem functions, many of them linked to organic carbon (C) dynamics in riparian soils, has therefore become a major goal of environmental policy. The fundamental understanding of the factors that drive the processes involved in C cycling in heterogeneous and dynamic systems such as floodplains is however only fragmentary. We quantified soil organic C pools (microbial C and water extractable organic C) and fluxes (soil respiration and net methane production) in functional process zones of adjacent channelized and widened sections of the Thur River, NE Switzerland, on a seasonal basis. The objective was to assess how spatial heterogeneity and temporal variability of these pools and fluxes relate to physicochemical soil properties on one hand, and to soil environmental conditions and flood disturbance on the other hand. Overall, factors related to seasonality and flooding (temperature, water content, organic matter input) affected soil C dynamics more than soil properties did. Coarse-textured soils on gravel bars in the restored section were characterized by low base-levels of organic C pools due to low TOC contents. However, frequent disturbance by flood pulses led to high heterogeneity with temporarily and locally increased C pools and soil respiration. By contrast, in stable riparian forests, the finer texture of the soils and corresponding higher TOC contents and water retention capacity led to high base-levels of C pools. Spatial heterogeneity was low, but major floods and seasonal differences in temperature had additional impacts on both pools and fluxes. Soil properties and base levels of C pools in the dam foreland of the channelized section were similar to the gravel bars of the restored section. By contrast, spatial heterogeneity, seasonal effects and flood disturbance were similar to the forests, except for indications of high CH4 production that are explained by long travel times of infiltrating water favoring reducing conditions. Overall, the restored section exhibited both a larger range and a higher heterogeneity of organic C pools and fluxes as well as a higher plant biodiversity than the channelized section. This suggests that restoration has indeed led to an increase in functional diversity.

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