Particulate Organic Carbon Content and Potential Mineralization as Affected by Tillage and Texture

1997 ◽  
Vol 61 (5) ◽  
pp. 1382-1386 ◽  
Author(s):  
A. J. Franzluebbers ◽  
M. A. Arshad
2021 ◽  
Vol 39 ◽  
Author(s):  
Eloísa A. Guerra-Hernández ◽  
Gerardo Cruz-Flores ◽  
Jorge D. Etchevers-Barra

Overexploitation of hydric resources and lack knowledge of interactions between riparian vegetation, water and soil, generates loss of environmental services and ecological degradation in many mountainous riparian environments. In order to characterizing riparian-soils and non-riparian soils, soil organic carbon content and particulate carbon was evaluated as ecological degradation indicators and also degree of association between physical and chemical water properties with those of riparian soils. Twenty sites were selected in lotic systems between 1900-3900 m on slopes Western in Iztaccíhuatl-Popocatépetl National-Park and influence zone. Also variability soil organic carbon content was evaluated at 1 and 5 m from stream (riparian soils) and also at more than 5 m from river (non-riparian soils) in different types of land use. Results showed signif icant relationships between soil organic carbon, electrical conductivity, pH, total nitrogen and available phosphorus with water properties (temperature, pH, conductivity, nitrates, ammonia, total phosphorus, dissolved oxygen, biochemical oxygen demand and particulate organic carbon). An inverse relationship was observed between soil organic carbon content of with particulate organic carbon, nitrates and nitrites, conductivity and dissolved oxygen. No signif icant differences were found in riparian-soils organic carbon (1 and 5 m), but there were signif icant differences in non-riparian soils organic carbon. Both soil organic carbon and water organic carbon particulate contents showed signif icant differences with respect to land use. Organic carbon contents in preserved riparian soils were higher than 240 Mg SOC ha-1 but in riparian-soils of degraded sites almost f ifty times smaller (5 Mg SOC ha-1).


2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop

Author(s):  
Emmanuelle Vaudour ◽  
Cécile Gomez ◽  
Philippe Lagacherie ◽  
Thomas Loiseau ◽  
Nicolas Baghdadi ◽  
...  

2021 ◽  
Author(s):  
Christoph Rosinger ◽  
Michael Bonkowski

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.


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