Soil organic carbon content: decreases partly attributed to dilution by increased depth of cultivation in southern Ontario

2020 ◽  
pp. 1-4
Author(s):  
C.J. Warren ◽  
D.D. Saurette ◽  
A.W. Gillespie
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Carbon Stocks ◽  
Soil Survey ◽  
Organic Carbon Content ◽  
Southern Ontario ◽  
Ap Horizon ◽  
Soil Carbon Stocks ◽  
Carbon Concentrations

Soil organic carbon contents and depths of Ap horizons (i.e., cultivated topsoil) from Ontario soil survey reports were reviewed, analyzed, and compared from 1950 to 2019. Organic carbon concentrations have declined from 2.85% to 2.34% in Ap horizons, whereas depths have increased by 40%. Considering the entire Ap horizon depth, we show that soil carbon stocks (kg C·ha−1) may be constant or increasing. Losses of organic carbon due to cultivation should not be discounted; however, dilution of organic carbon within a deeper plow layer may contribute significantly to observed decreases in organic carbon concentrations in topsoil.

scholarly journals Correlations between soil organic carbon, land use and soil type in Serbia

2020 ◽  
pp. 9-18
Author(s):  
Dragana Vidojevic ◽  
Maja Manojlovic ◽  
Aleksandar Djordjevic ◽  
Ljiljana Nesic ◽  
Tihomir Predic
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Soil Type ◽  
Carbon Stocks ◽  
Organic Carbon Content ◽  
Corine Land Cover ◽  
Soil Layers ◽  
Mean Values

Correlation between soil organic carbon (SOC) and land use and soil type were investigated in the soils of the Republic of Serbia. The database included a total of 1,140 soil profiles. To establish the correlation between organic carbon content and soil type, a soil map of Serbia was adapted to the WRB classification and divided into 15,437 polygons (map units). The SOC stock values were calculated for each reference soil group based on mean values of SOC at 0-30 and 0-100 cm and their areas. The largest SOC stocks for the soil layers 0-30 cm were found in Cambisol 194.76 x 1012 g and Leptosol 186.43 x 1012 g and for the soil layers 0-100 cm in Cambisol 274.87 x 1012 g and Chernozem 230.43 x 1012 g. Using the Corine Land Cover (CLC) database, the major categories of land use were defined. Based on the obtained mean values of organic carbon content for the soil layers 0-30 and 0-100 cm and the areas indicated by Corine Land Cover categories of land use, the organic carbon stocks in agricultural soil, forest soil, semi-natural areas, and artificial areas were calculated. The correlation of organic carbon stocks and the different land use categories, soil reference group, and soil depth was studied for reference groups that occupy the major part of central Serbia, such as Cambisol (taking up 37.76% of the territory) and Leptosol (22.22% of the territory), and have a sufficient number of sites that were required for this type of analysis.

Space-time monitoring of soil organic carbon content across a semi-arid region of Australia

2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Arid Region ◽  
Space Time ◽  
Organic Carbon Content ◽  
Soil Organic Carbon Content ◽  
Semi Arid Region ◽  
Semi Arid

scholarly journals Soil age and soil organic carbon content shape biochemical responses to multiple freeze–thaw events in soils along a postmining agricultural chronosequence

2021 ◽  
Author(s):  
Christoph Rosinger ◽  
Michael Bonkowski
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Organic Carbon Content ◽  
Freeze Thaw ◽  
Biochemical Responses ◽  
Microbial Responses ◽  
Soil Age ◽  
Carbon Losses

AbstractFreeze–thaw (FT) events exert a great physiological stress on the soil microbial community and thus significantly impact soil biogeochemical processes. Studies often show ambiguous and contradicting results, because a multitude of environmental factors affect biogeochemical responses to FT. Thus, a better understanding of the factors driving and regulating microbial responses to FT events is required. Soil chronosequences allow more focused comparisons among soils with initially similar start conditions. We therefore exposed four soils with contrasting organic carbon contents and opposing soil age (i.e., years after restoration) from a postmining agricultural chronosequence to three consecutive FT events and evaluated soil biochgeoemical responses after thawing. The major microbial biomass carbon losses occurred after the first FT event, while microbial biomass N decreased more steadily with subsequent FT cycles. This led to an immediate and lasting decoupling of microbial biomass carbon:nitrogen stoichiometry. After the first FT event, basal respiration and the metabolic quotient (i.e., respiration per microbial biomass unit) were above pre-freezing values and thereafter decreased with subsequent FT cycles, demonstrating initially high dissimilatory carbon losses and less and less microbial metabolic activity with each iterative FT cycle. As a consequence, dissolved organic carbon and total dissolved nitrogen increased in soil solution after the first FT event, while a substantial part of the liberated nitrogen was likely lost through gaseous emissions. Overall, high-carbon soils were more vulnerable to microbial biomass losses than low-carbon soils. Surprisingly, soil age explained more variation in soil chemical and microbial responses than soil organic carbon content. Further studies are needed to dissect the factors associated with soil age and its influence on soil biochemical responses to FT events.

scholarly journals The southern Brazilian grassland biome: soil carbon stocks, fluxes of greenhouse gases and some options for mitigation

2012 ◽  
Vol 72 (3 suppl) ◽  
pp. 673-681 ◽  
Author(s):  
VD Pillar ◽  
CG Tornquist ◽  
C Bayer
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Greenhouse Gases ◽  
Soil Carbon ◽  
Carbon Stocks ◽  
Soil Tillage ◽  
Nitrous Oxide Emissions ◽  
Greenhouse Gases Emissions ◽  
Soil Carbon Stocks ◽  
Grassland Biome

The southern Brazilian grassland biome contains highly diverse natural ecosystems that have been used for centuries for grazing livestock and that also provide other important environmental services. Here we outline the main factors controlling ecosystem processes, review and discuss the available data on soil carbon stocks and greenhouse gases emissions from soils, and suggest opportunities for mitigation of climatic change. The research on carbon and greenhouse gases emissions in these ecosystems is recent and the results are still fragmented. The available data indicate that the southern Brazilian natural grassland ecosystems under adequate management contain important stocks of organic carbon in the soil, and therefore their conservation is relevant for the mitigation of climate change. Furthermore, these ecosystems show a great and rapid loss of soil organic carbon when converted to crops based on conventional tillage practices. However, in the already converted areas there is potential to mitigate greenhouse gas emissions by using cropping systems based on no soil tillage and cover-crops, and the effect is mainly related to the potential of these crop systems to accumulate soil organic carbon in the soil at rates that surpass the increased soil nitrous oxide emissions. Further modelling with these results associated with geographic information systems could generate regional estimates of carbon balance.

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