scholarly journals Plant rhizodeposition: A key factor for soil organic matter formation in stable fractions

2021 ◽  
Vol 7 (16) ◽  
pp. eabd3176
Author(s):  
Sebastián H. Villarino ◽  
Priscila Pinto ◽  
Robert B. Jackson ◽  
Gervasio Piñeiro
Keyword(s):  
Organic Carbon ◽  
Root Biomass ◽  
Carbon Formation ◽  
Decomposition Rates ◽  
Tracer Studies ◽  
Isotope Tracer ◽  
Key Factor ◽  
Organic Carbon Fractions ◽  
Soil Organic Matter Formation ◽  
Formation Efficiency

Soil organic carbon formation remains poorly understood despite its importance for human livelihoods. Uncertainties remain for the relative contributions of aboveground, root, and rhizodeposition inputs to particulate (POC) and mineral-associated (MAOC) organic carbon fractions. Combining a novel framework with isotope tracer studies, we quantified POC and MAOC formation efficiencies (% of C-inputs incorporated into each fraction). We found that rhizodeposition inputs have the highest MAOC formation efficiency (46%) as compared to roots (9%) or aboveground inputs (7%). In addition, rhizodeposition unexpectedly reduced POC formation, likely because it increased decomposition rates of new POC. Conversely, root biomass inputs have the highest POC formation efficiency (19%). Therefore, rhizodeposition and roots appear to play opposite but complementary roles for building MAOC and POC fractions.

Organic carbon fractions in temperate mangrove and saltmarsh soils

Soil Research ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 34
Author(s):  
V. N. L. Wong ◽  
R. E. Reef ◽  
C. Chan ◽  
K. S. Goldsmith
Keyword(s):  
Organic Carbon ◽  
Coastal Wetlands ◽  
Soil Moisture Content ◽  
Vertical Displacement ◽  
Size Fractionation ◽  
Decomposition Rates ◽  
Recalcitrant Carbon ◽  
Organic Carbon Fractions ◽  
Ingrowth Bags ◽  
Soc Stocks

Coastal wetlands, such as mangrove and saltmarsh environments, can store significant amounts of soil organic carbon (SOC); however, most studies focus on tropical and subtropical environments. We assessed SOC stocks and fractions in temperate mangrove (two sites) and saltmarsh (sites SM1, SM2 and SM3) environments in southern Australia. The SOC fractions were separated according to particulate organic carbon (POC), humic carbon (HC) and recalcitrant carbon (RC) by size fractionation. Saltmarsh sites generally had the highest SOC content (up to 12.4% SOC). The POC fraction was the highest at the surface in the saltmarsh site and decreased relative to the HC and RC fractions with depth. Conversely, the proportion of POC at the mangrove sites did not decrease with depth, forming up to 76% of the SOC. The vertical displacement of soil of up to 5.8 mm year–1 at the saltmarsh sites, measured using root ingrowth bags, suggest significant contributions of POC via root materials. Retention of these POC inputs are likely to be related to waterlogging, which decreases decomposition rates – with much lower soil moisture content at SM1, where the lowest POC content occurred below the surface, compared with SM2 and SM3.

scholarly journals Changes in organic carbon fractions and sources in deltaic topsoil and subsoil layers: autochthonous and allochthonous inputs

2021 ◽  
Author(s):  
Yuan Li ◽  
Chuancheng Fu ◽  
Lin Zeng ◽  
Qian Zhou ◽  
Haibo Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Fractions ◽  
Allochthonous Inputs ◽  
Organic Carbon Fractions

Soil organic matter formation is controlled by the chemistry and bioavailability of organic carbon inputs across different land uses

2021 ◽  
Vol 770 ◽  
pp. 145307
Author(s):  
Mohammad Bahadori ◽  
Chengrong Chen ◽  
Stephen Lewis ◽  
Sue Boyd ◽  
Mehran Rezaei Rashti ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Land Uses ◽  
Soil Organic Matter Formation

Effects of nitrogen deposition on soil organic carbon fractions in the subtropical forest ecosystems of S China

2012 ◽  
Vol 175 (6) ◽  
pp. 947-953 ◽  
Author(s):  
Xiaomei Chen ◽  
Yuelin Li ◽  
Jiangming Mo ◽  
Dennis Otieno ◽  
John Tenhunen ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Nitrogen Deposition ◽  
Forest Ecosystems ◽  
Subtropical Forest ◽  
Carbon Fractions ◽  
Organic Carbon Fractions ◽  
Soil Organic Carbon Fractions

Landuse impacts on soil organic carbon fractions in different rainfall areas of a subtropical dryland

2017 ◽  
Vol 63 (10) ◽  
pp. 1337-1345 ◽  
Author(s):  
Sara Niaz ◽  
Shahzada Sohail Ijaz ◽  
Asma Hassan ◽  
Muhammad Sharif
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Fractions ◽  
Organic Carbon Fractions ◽  
Soil Organic Carbon Fractions
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