Influences of Biochar Aging Processes by Eco-Environmental Conditions

Biochar is receiving increasing attention as a promising functional material in contaminated soil remediation. However, aging processes of biochar can usually take place and affect its remediation function, because surface properties of biochar are expected to change through a variety of biotic and abiotic processes. In this review, some important influencing factors of biochar aging processes were discussed, including temperature, and soil-physical, soil-chemical and soil-biological components. It pointed out that biochar aging processes may be promoted by high temperature, protected by soil components, particularly soil organic matter (SOM), and interactions with soil microorganisms. To further prolong application of biochar in nature, biochar aging can be mitigated by its influencing factors.

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Microbial necromass as a source for soil organic matter formation - implications for soil processes

10.5194/egusphere-egu2020-13094 ◽

2020 ◽

Author(s):

Anja Miltner ◽

Tiantian Zheng ◽

Chao Liang ◽

Matthias Kästner

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Microbial Biomass ◽

Surface Properties ◽

Soil Microorganisms ◽

Plant Litter ◽

Plant Residues ◽

Elemental Stoichiometry ◽

Stress Changes ◽

Cell Envelopes

The vital role of soil microorganisms as catalysts for soil organic matter (SOM) formation has long been recognised. Plant residues are now considered to be transformed by soil microorganisms who use the plant litter as a carbon source for microbial biomass formation. How much carbon is retained as microbial biomass during transformation of plant material, critically depends on substrate availability, carbon use efficiency of the microorganisms, and maximum microbial growth. In addition, microorganisms presumably recycle biomass building blocks from plant or microbial material to avoid energy expenditure for biomass synthesis. After cell death, a part of the microbial necromass is cycling through the microbial food web; the other part is stabilised in soil (Miltner et al., 2012). Potential stabilisation mechanisms are similar to those for SOM in general, with organo-mineral interactions, in particular encapsulation and physical isolation, being important mechanisms. Independent of which pathway the plant-derived carbon goes, SOM constitutes a continuum of plant and microbial necromass at various stages of decay. The contribution of microbial necromass to the topsoil organic matter pool has recently been estimated to range from 30 to 60% (Liang et al., 2019). Such high contributions of microbial necromass have a number of important implications for understanding SOM transformation and sequestration processes. Most obviously, the chemical identity of the organic material changes. For example, while retaining a substantial part of the carbon, the elemental stoichiometry changes substantially. Some microbial necromass materials are rather long-lasting in soil. In general, cell envelope residues have a higher stability than bulk biomass carbon. Proteins have also been shown to be rather persistent in soil, presumably due to conformational changes and the spatial arrangement of microbial necromass material, e.g. fragments of cell envelopes presumably pile up in multiple layers and the material forms clusters of macromolecular size. Residual electron-shuttle biomolecules (e.g. oxidoreductases, Fe-S-cluster, quinoid complexes of respiratory chains) may persist and retain some activity and thus contribute to redox reactions in soil. In addition, the necromass is expected to cover soil particle surfaces and thus determine the surface properties of these particles. In particular, these materials contribute to the water storage potential. They affect water retention and nutrient diffusion as well as microbial motility. Adaption of microbes to water stress changes their cell surface properties and molecular composition and thus may determine overall soil wettability. Knowledge on the contribution of microbial necromass to SOM would thus be essential for modelling SOM formation and optimising soil management practices for maintaining soil functions.&#160;References:Miltner A, Bombach P, Schmidt-Br&#252;cken B, K&#228;stner M (2012) SOM genesis: Microbial biomass as a significant source. Biogeochemistry 111: 41-55.Liang C, Amelung W, Lehmann J, K&#228;stner M (2019) Quantitative assessment of microbial necromass contribution to soil organic matter. Global Change Biology 25: 3578-3590.

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Potential of the soil microbial biomass C to tolerate and degrade persistent organic pollutants

Soil and Water Research ◽

10.17221/2096-swr ◽

2008 ◽

Vol 3 (No. 1) ◽

pp. 12-20 ◽

Cited By ~ 3

Author(s):

G. Mühlbachová

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Microbial Biomass ◽

Contaminated Soil ◽

Soil Microorganisms ◽

Soil Microbial Biomass ◽

Microbial Biomass C ◽

Microbial Activities ◽

Soil Microbial Biomass C ◽

Soil Microbial

A 12-day incubation experiment with the addition of glucose to soils contaminated with persistent organic pollutants (POPs) was carried out in order to estimate the potential microbial activities and the potential of the soil microbial biomass C to degrade 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT), polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAHs). The microbial activities were affected in different ways depending on the type of pollutant. The soil organic matter also played an important role. The microbial activities were affected particularly by high concentrations of PAHs in the soils. Soil microorganisms in the PAHs contaminated soil used the added glucose to a lesser extent than in the non-contaminated soil, which in the contaminated soil resulted in a higher microbial biomass content during the first day of incubation. DDT, DDD and DDE, and PCB affected the soil microbial activities differently and, in comparison with control soils, decreased the microbial biomass C during the incubation. The increased microbial activities led to a significant decrease of PAH up to 44.6% in the soil long-term contaminated with PAHs, and up to 14% in the control soil after 12 days of incubation. No decrease of PAHs concentrations was observed in the soil which was previously amended with sewage sludges containing PAHs and had more organic matter from the sewage sludges. DDT and its derivates DDD and DDE decreased by about 10%, whereas the PCB contents were not affected at all by microbial activities. Studies on the microbial degradation of POPs could be useful for the development of methods focused on the remediation of the contaminated sites. An increase of soil microbial activities caused by addition of organic substrates can contribute to the degradation of pollutants in some soils. However, in situ biodegradation may be limited because of a complex set of environmental conditions, particularly of the soil organic matter. The degradability and availability of POPs for the soil microorganisms has to be estimated individually for each contaminated site.

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Fractionation of Heavy Metals in Multi-Contaminated Soil Treated with Biochar Using the Sequential Extraction Procedure

Biomolecules ◽

10.3390/biom11030448 ◽

2021 ◽

Vol 11 (3) ◽

pp. 448

Author(s):

Mahrous Awad ◽

Zhongzhen Liu ◽

Milan Skalicky ◽

Eldessoky S. Dessoky ◽

Marian Brestic ◽

...

Keyword(s):

Heavy Metals ◽

Organic Matter ◽

Soil Organic Matter ◽

Soil Ph ◽

Contaminated Soil ◽

Contaminated Soils ◽

Extraction Procedure ◽

Sequential Fractionation ◽

Relationship Of ◽

The Relationship

Heavy metals (HMs) toxicity represents a global problem depending on the soil environment’s geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.

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Assimilation of CO2 by soil microorganisms and transformation into soil organic matter

Organic Geochemistry ◽

10.1016/j.orggeochem.2004.05.001 ◽

2004 ◽

Vol 35 (9) ◽

pp. 1015-1024 ◽

Cited By ~ 71

Author(s):

Anja Miltner ◽

Hans-Hermann Richnow ◽

Frank-Dieter Kopinke ◽

Matthias Kästner

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Microorganisms

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Heavy Metal Retention by Soil Organic Matter under Changing Environmental Conditions

Biogeodynamics of Pollutants in Soils and Sediments ◽

10.1007/978-3-642-79418-6_3 ◽

1995 ◽

pp. 53-85 ◽

Cited By ~ 16

Author(s):

R. Schulin ◽

G. Geiger ◽

G. Furrer

Keyword(s):

Heavy Metal ◽

Organic Matter ◽

Soil Organic Matter ◽

Environmental Conditions ◽

Metal Retention

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Soil microorganisms, soil organic matter and soil fertility

The Role of Organic Matter in Modern Agriculture ◽

10.1007/978-94-009-4426-8_7 ◽

1986 ◽

pp. 159-168 ◽

Cited By ~ 8

Author(s):

Y. Henis

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Fertility ◽

Soil Microorganisms

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Ethalfluralin Activity in Cucumber (Cucumis sativus)

Weed Science ◽

10.1017/s0043174500041059 ◽

1982 ◽

Vol 30 (5) ◽

pp. 498-502 ◽

Cited By ~ 2

Author(s):

Jeffrey F. Derr ◽

Thomas J. Monaco

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Weed Control ◽

Cucumis Sativus ◽

Environmental Conditions ◽

Heavy Rain ◽

Field Studies ◽

Herbicidal Activity ◽

Fresh Weight ◽

Fresh Market

In greenhouse studies, soil organic matter reduced the herbicidal activity of ethalfluralin (N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine). Fifty percent inhibition (I5.0) values for barnyardgrass [Echinochloa crus-galli(L.) Beauv.] stand, injury, and shoot fresh weight increased as the soil organic-matter level increased. No difference in ethalfluralin tolerance was found among 16 cucumber (Cucumis sativusL.) cultivars. When grouped according to market type, fresh market cultivars tended to be injured more than pickling cultivars by excess ethalfluralin. Both shoots and roots of cucumber absorbed the herbicide, but exposure of roots to ethalfluralin was more toxic than exposure of shoots. Field studies indicated that with certain edaphic and environmental conditions, cucumbers can be injured by preemergence applications of ethalfluralin. Injury was greatest in a low organic-matter soil following a heavy rain. Ethalfluralin at 1.3 kg/ha gave adequate weed control in 1 and 3% organic-matter soils, but not in a 9% organic-matter soil.

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