Influence of plant roots on rhizosphere soil solution composition of long-term contaminated soils

Geoderma ◽  
2010 ◽  
Vol 155 (1-2) ◽  
pp. 86-92 ◽  
Author(s):  
Kwon-Rae Kim ◽  
Gary Owens ◽  
Ravi Naidu ◽  
Soon-lk Kwon
Keyword(s):  
Soil Solution ◽  
Contaminated Soils ◽  
Rhizosphere Soil ◽  
Plant Roots ◽  
Solution Composition

Soil solution composition and aggregate stability changes caused by long-term farming at four contrasting sites in South Australia

Soil Research ◽  
1996 ◽  
Vol 34 (4) ◽  
pp. 511 ◽  
Author(s):  
R Naidu ◽  
S Mcclure ◽  
NJ Mckenzie ◽  
RW Fitzpatrick
Keyword(s):  
Organic Matter ◽  
Soil Solution ◽  
South Australia ◽  
Aggregate Stability ◽  
Fungal Hypha ◽  
Organic Carbon Content ◽  
Solution Composition ◽  
Horizon Scanning ◽  
Undisturbed Soils

The effect of long-term farming on the cation exchange capacity (CEC), organic carbon content, soil solution composition, and aggregate stability was investigated using contrasting soils from 4 sites in the Mid North of South Australia. Undisturbed and farmed profiles were characterised at each site. Farming led to a 10–50% decrease, approximately, in organic matter and CEC in the surface horizon. Scanning electron microscopic study of the surface and selected subsurface soils revealed poor aggregation, compaction, reduced porosity, and a decrease in aggregate particle size in the farmed surface soils. Intra-aggregate binding in the undisturbed soils appeared to be largely due to fungal hypha, with the roots largely contributing to inter-aggregate binding of soil particles. Electrical conductivity (EC) of soil solutions was generally 2–3 times higher in the undisturbed soils than farmed soils, suggesting increased leaching of ions associated with loss of tree cover. This was also supported by a decrease in the concentrations of mobile ions such as Cl-and Na+ in the farmed soils. The concentrations of Na+ and K+ decreased with farming leading to a decrease in the Gapon selectivity constant for Na–Ca and K–Ca exchange. The changes in soil solution composition together with the decline in organic matter concentrations resulted in increased sensitivity of soils to dispersion.

Impact of long-term organic residue recycling in agriculture on soil solution composition and trace metal leaching in soils

2014 ◽  
Vol 499 ◽  
pp. 560-573 ◽  
Author(s):  
Philippe Cambier ◽  
Valérie Pot ◽  
Vincent Mercier ◽  
Aurélia Michaud ◽  
Pierre Benoit ◽  
...  
Keyword(s):  
Trace Metal ◽  
Soil Solution ◽  
Metal Leaching ◽  
Organic Residue ◽  
Solution Composition

scholarly journals Remediation of mercury-contaminated soils and sediments using biochar: a critical review

Biochar ◽  
2021 ◽  
Author(s):  
Qian Yang ◽  
Yongjie Wang ◽  
Huan Zhong
Keyword(s):  
Health Risks ◽  
Contaminated Soils ◽  
Functional Materials ◽  
Redox Conditions ◽  
Existing Problems ◽  
Soils And Sediments ◽  
Underlying Mechanisms ◽  
Biochar Amendment

AbstractThe transformation of mercury (Hg) into the more toxic and bioaccumulative form methylmercury (MeHg) in soils and sediments can lead to the biomagnification of MeHg through the food chain, which poses ecological and health risks. In the last decade, biochar application, an in situ remediation technique, has been shown to be effective in mitigating the risks from Hg in soils and sediments. However, uncertainties associated with biochar use and its underlying mechanisms remain. Here, we summarize recent studies on the effects and advantages of biochar amendment related to Hg biogeochemistry and its bioavailability in soils and sediments and systematically analyze the progress made in understanding the underlying mechanisms responsible for reductions in Hg bioaccumulation. The existing literature indicates (1) that biochar application decreases the mobility of inorganic Hg in soils and sediments and (2) that biochar can reduce the bioavailability of MeHg and its accumulation in crops but has a complex effect on net MeHg production. In this review, two main mechanisms, a direct mechanism (e.g., Hg-biochar binding) and an indirect mechanism (e.g., biochar-impacted sulfur cycling and thus Hg-soil binding), that explain the reduction in Hg bioavailability by biochar amendment based on the interactions among biochar, soil and Hg under redox conditions are highlighted. Furthermore, the existing problems with the use of biochar to treat Hg-contaminated soils and sediments, such as the appropriate dose and the long-term effectiveness of biochar, are discussed. Further research involving laboratory tests and field applications is necessary to obtain a mechanistic understanding of the role of biochar in reducing Hg bioavailability in diverse soil types under varying redox conditions and to develop completely green and sustainable biochar-based functional materials for mitigating Hg-related health risks.

VESSEL FOR LONG TERM SOIL-SOLUTION EQUILIBRATION

1968 ◽  
Vol 48 (2) ◽  
pp. 221-221
Author(s):  
J. S. Clark ◽  
R. G. Hill
Keyword(s):  
Soil Solution

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