scholarly journals Effects of root exudates of woody species on the soil anti-erodibility in the rhizosphere in a karst region, China

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3029 ◽  
Author(s):  
Zhen Hong Wang ◽  
Hong Fang ◽  
Mouhui Chen
Keyword(s):  
Organic Matter ◽  
Root Exudates ◽  
Woody Species ◽  
Interspecific Variation ◽  
Root Density ◽  
Gas Chromatography Mass Spectrometry ◽  
Karst Region ◽  
Soil Stability ◽  
Interspecific Differences

IntroductionRhizospheres, the most active interfaces between plants and soils, play a central role in the long-term maintenance of the biosphere. The anti-erodibility of soils (AES) regulated by the root exudates is crucial to the soil stability in the rhizospheres. However, scientists still debate (1) the key organic matter of the root exudates affecting the AES and (2) the interspecific variation of these root exudates.MethodsWe used an incubation of soils to test the effects of the root exudates from eight woody plant species on the change in soil aggregation and identified the organic matter in these root exudates with gas chromatography-mass spectrometry (GC-MS) and biochemical methods. Furthermore, the relationships between the organic matter in the exudates and the AES in the rhizospheres of 34 additional tree species were analyzed.ResultsThe water-stable aggregates of the soils incubated with the root exudates increased by 15%–50% on average compared with control samples. The interspecific differences were significant. The root exudates included hundreds of specific organic matter types; hydrocarbon, total sugar, total amino acids, and phenolic compounds were crucial to the AES. These organic matter types could explain approximately 20–75% of the variation in the total effect of the root exudates on the AES, which was quantified based on the aggregate status, degree of aggregation, dispersion ratio, and dispersion coefficient.DiscussionThe effects of the root exudates on the AES and the interspecific variation are as important as that of root density, litters, and vegetation covers. Many studies explored the effects of root density, litters, vegetation covers, and vegetation types on the AES, but little attention has been paid to the effects of the root exudates on the AES. Different plants secrete different relative contents of organic matter resulting in the variation of the effect of the root exudates on the AES. Our study quantified the causal relationships between the root exudates and the AES using modeling experiments in laboratory and field observations and indicated the interspecific variation of the AES and organic matter of the root exudates.ConclusionsMore organic compounds of the exudates related to the AES were recognized in this study. These results enhance the understanding of the soil stability at a slope and can be applied to ecosystem restoration.

scholarly journals Effects of root exudates of woody species on the soil anti-erodibility in the rhizosphere in a karst region, China

2017 ◽  
Author(s):  
Zhenhong Wang ◽  
Hong Fang ◽  
Mouhui Chen
Keyword(s):  
Organic Matter ◽  
Root Exudates ◽  
Woody Species ◽  
Interspecific Variation ◽  
Root Density ◽  
Karst Region ◽  
Interspecific Differences ◽  
The Stability ◽  
Term Maintenance

Introduction: Rhizospheres, the most active interfaces between plants and soils, play a central role in a long-term maintenance of the biosphere. The anti-erodibility of soils (AES) regulated by the root exudates is crucial to the stability of the rhizospheres. However, scientists still remain unclear regarding the key organic matter in the root exudates to affect the AES and interspecific variation. Methods: We used an incubation of soils to test the effects of the root exudates from 8 woody plant species on a change in soil aggregation, and identified the organic matter in these root exudates with gas chromatograph-mass spectrometer (GC-MS) and biochemical methods. Furthermore, the relationships between the organic matter in the exudates and the AES in the rhizosperes of the 34 additional tree species were analyzed. Results: The water-stable aggregates of the soils incubated with the root exudates increased by 15-50% on average compared with controls, and the interspecific differences were significant. The root exudates included hundreds of specific organic matter, in which hydrocarbon, total sugar, total amino acids and phenolic compounds were crucial to the AES. These types of the matter could explain about 20-75% of the variation in total effects of the root exudates on the AES quantified by aggregate status, degree of aggregation, dispersion ratio and dispersion coefficient. Discussion: Effects of the root exudates on the AES and the interspecific variation are as important as those of root density, litters and vegetation covers. A range of studies have explored the effects of root density, litters, vegetation covers and types on the AES, but little attention has been given to the effects of the root exudates on the AES. Different plants secrete the different relative contents of the organic matter resulting in the variation of the effects of the root exudates on the AES. Our study quantified the causal relationships between the root exudates and the AES from modeling experiments in laboratory to actual effects in the field, and indicated the interspecific variation of the AES and the organic matter in the root exudates. Conclusions: The study recognized more organic compounds in the exudates related to the AES. These results can enhance the understanding of the stability of the soils in a slope and be applied to ecosystem restoration.

scholarly journals Effects of root exudates of woody species on the soil anti-erodibility in the rhizosphere in a karst region, China

2016 ◽  
Author(s):  
Zhen Hong Wang ◽  
Hong Fang ◽  
Mouhui Chen
Keyword(s):  
Organic Matter ◽  
Root Exudates ◽  
Woody Species ◽  
Interspecific Variation ◽  
Root Density ◽  
Karst Region ◽  
Interspecific Differences ◽  
The Stability ◽  
Term Maintenance

Introduction: The rhizospheres, the most active interfaces between plants and soils, play a central role in a long-term maintenance of the biosphere. The anti-erodibility of soils (AES) regulated by the root exudates is crucial to the stability of the rhizospheres. However, scientists still remain unclear regarding the key organic matter in the root exudates to affect the AES and interspecific variation. Methods: We used an incubation of soils to test the effects of the root exudates from 8 woody plant species on a change in soil aggregation, and identified the organic matter in these root exudates with gas chromatograph-mass spectrometer (GC-MS) and biochemical methods. Furthermore, the relationships between the organic matter in the exudates and the AES in the rhizosperes of the 34 additional tree species were analyzed. Results: The water-stable aggregates of the soils incubated with the root exudates increased by 15-50% on average compared with controls, and the interspecific differences were significant. The root exudates included hundreds of specific organic matter, in which hydrocarbon, total sugar, total amino acids and phenolic compounds were crucial to the AES. These types of the matter could explain about 20-75% of the variation in total effects of the root exudates on the AES quantified by aggregate status, degree of aggregation, dispersion ratio and dispersion coefficient. Discussion: Effects of the root exudates on the AES and the interspecific variation are as important as those of root density, litters and vegetation covers. A range of studies have explored the effects of root density, litters, vegetation covers and types on the AES, but little attention has been given to the effects of the root exudates on the AES. Different plants secrete the different relative contents of the organic matter resulting in the variation of the effects of the root exudates on the AES. Our study quantified the causal relationships between the root exudates and the AES from modeling experiments in laboratory to actual effects in the field, and indicated the interspecific variation of the AES and the organic matter in the root exudates. Conclusions: The study recognized more organic compounds in the exudates related to the AES. These results can enhance the understanding of the stability of the soils in a slope and be applied to ecosystem restoration.

scholarly journals Effects of root exudates of woody species on the soil anti-erodibility in the rhizosphere in a karst region, China

2017 ◽  
Author(s):  
Zhenhong Wang ◽  
Hong Fang ◽  
Mouhui Chen
Keyword(s):  
Organic Matter ◽  
Root Exudates ◽  
Woody Species ◽  
Interspecific Variation ◽  
Root Density ◽  
Karst Region ◽  
Interspecific Differences ◽  
The Stability ◽  
Term Maintenance

Introduction: Rhizospheres, the most active interfaces between plants and soils, play a central role in a long-term maintenance of the biosphere. The anti-erodibility of soils (AES) regulated by the root exudates is crucial to the stability of the rhizospheres. However, scientists still remain unclear regarding the key organic matter in the root exudates to affect the AES and interspecific variation. Methods: We used an incubation of soils to test the effects of the root exudates from 8 woody plant species on a change in soil aggregation, and identified the organic matter in these root exudates with gas chromatograph-mass spectrometer (GC-MS) and biochemical methods. Furthermore, the relationships between the organic matter in the exudates and the AES in the rhizosperes of the 34 additional tree species were analyzed. Results: The water-stable aggregates of the soils incubated with the root exudates increased by 15-50% on average compared with controls, and the interspecific differences were significant. The root exudates included hundreds of specific organic matter, in which hydrocarbon, total sugar, total amino acids and phenolic compounds were crucial to the AES. These types of the matter could explain about 20-75% of the variation in total effects of the root exudates on the AES quantified by aggregate status, degree of aggregation, dispersion ratio and dispersion coefficient. Discussion: Effects of the root exudates on the AES and the interspecific variation are as important as those of root density, litters and vegetation covers. A range of studies have explored the effects of root density, litters, vegetation covers and types on the AES, but little attention has been given to the effects of the root exudates on the AES. Different plants secrete the different relative contents of the organic matter resulting in the variation of the effects of the root exudates on the AES. Our study quantified the causal relationships between the root exudates and the AES from modeling experiments in laboratory to actual effects in the field, and indicated the interspecific variation of the AES and the organic matter in the root exudates. Conclusions: The study recognized more organic compounds in the exudates related to the AES. These results can enhance the understanding of the stability of the soils in a slope and be applied to ecosystem restoration.

scholarly journals Long-term watershed management is an effective strategy to reduce organic matter export and disinfection by-product precursors in source water

2019 ◽  
Vol 28 (10) ◽  
pp. 804 ◽  
Author(s):  
Hamed Majidzadeh ◽  
Huan Chen ◽  
T. Adam Coates ◽  
Kuo-Pei Tsai ◽  
Christopher I. Olivares ◽  
...  
Keyword(s):  
Organic Matter ◽  
South Carolina ◽  
Watershed Management ◽  
Management Practices ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Long Term Effects ◽  
Pyrolysis Gas ◽  
Water Extracts

Watershed management practices such as prescribed fire, harvesting and understory mastication can alter the chemical composition and thickness of forest detritus, thus affecting the quantity and quality of riverine dissolved organic matter (DOM). Long-term effects of watershed management on DOM composition were examined through parallel field and extraction-based laboratory studies. The laboratory study was conducted using detritus samples collected from a pair of managed and unmanaged watersheds in South Carolina, USA. Results showed that dissolved organic carbon (DOC), total dissolved nitrogen (TDN) and ammonium (NH4+-N) concentrations were higher in water extracts from the unmanaged watershed than from the managed watershed (P<0.01). Pyrolysis gas chromatography–mass spectrometry analysis showed that water extracts from the unmanaged watershed contained more aromatic compounds than extracts from the managed watershed. For the field study, monthly water samples were collected for 1 year (2015) from the paired watersheds. DOC and TDN concentrations, as well as DOM aromaticity, were significantly higher in the unmanaged watershed than in the managed watershed for most of the year (P<0.05) and were linked to detrital thickness, precipitation and flow patterns. The formation potential of two regulated disinfection by-products was lower in the unmanaged watershed for most of 2015 (P<0.05). From this study, it appears that long-term watershed management practices may alter detrital mass and chemistry in ways that improve water quality.

scholarly journals Simple Derivatization–Gas Chromatography–Mass Spectrometry for Fatty Acids Profiling in Soil Dissolved Organic Matter

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5278
Author(s):  
Neil Yohan Musadji ◽  
Claude Geffroy-Rodier
Keyword(s):  
Fatty Acids ◽  
Gas Chromatography ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Climate Change Impacts ◽  
Major Change ◽  
Terrestrial Ecosystems ◽  
Gas Chromatography Mass Spectrometry ◽  
Global Carbon

Dissolved organic matter is an important component of the global carbon cycle that allows the distribution of carbon and nutrients. Therefore, analysis of soil dissolved organic matter helps us to better understand climate change impacts as it is the most dynamic and reactive fraction in terrestrial ecosystems. Its characterization at the molecular level is still challenging due to complex mixtures of hundreds of compounds at low concentration levels in percolating water. This work presents simple methods, such as thermochemolysis– or derivatization–gas chromatography, as an alternative for the analysis of fatty acids in dissolved organic matter without any purification step. The variables of the protocols were examined to optimize the processing conditions for the C9–C18 range. As a proof of concept, fatty acid distributions of soil percolating water samples from a long-term field experiment were successfully assessed. The variability of dissolved organic acid distributions was pronounced through depth profile and soil treatment but no major change in composition was observed. However, although the optimization was done from C9 to C18, detection within the C6-C32 fatty acids range was performed for all samples.

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