This study focused on metal release from technosols induced by synthetic root exudate(SRE).The effect of SRE composition on metal release was studied using six technosols.This was done by treating the technosols with ...This study focused on metal release from technosols induced by synthetic root exudate(SRE).The effect of SRE composition on metal release was studied using six technosols.This was done by treating the technosols with SRE solutions having varying concentrations of low molecular weight organic acids (LMWOAs),namely oxalic,citric,and malic acids.Consequently,the physico-chemical parameters (p H and electric conductivity),Ca,Mg,Fe,Zn,and Cu release (by atomic absorption spectroscopy,AAS),chemical changes (by Fourier transform infrared,FT-IR),and organic parameters (by fluorescence) were investigated.Metal release showed to be dependent on the SRE composition and technosol characteristics.Citric acid selectively released Ca,Mg,Zn,and Cu from technosols in a concentration-dependent manner;oxalic acid showed a significant role in the release of Mg and Fe.Under relatively high LMWOA concentrations,particulate organo-mineral complexes precipitated.Additionally,technosol weathering was seen by the dissolution of humic substances and ferriallophanes,which in turn caused metal release.However,re-precipitation of these phases showed to re-sorb metals,thus underestimating the role of LMWOAs in metal release.Therefore,the selective metal leaching was highly dependent on the SRE composition and LMWOA concentrations on one hand,and on the mineral,organic,and organo-mineral components of the technosols on the other.The understanding of such processes is crucial for proposing and implementing environmental management strategies to reduce metal leaching or for the beneficial re-usage of metals (e.g.,for agromining) from technosols.展开更多
Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest...Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.展开更多
基金financed by the research grant programs of the Lebanese University (le projet est soutenu par le programme de subvention de la recherche scientifique à l’Université Libanaise)。
文摘This study focused on metal release from technosols induced by synthetic root exudate(SRE).The effect of SRE composition on metal release was studied using six technosols.This was done by treating the technosols with SRE solutions having varying concentrations of low molecular weight organic acids (LMWOAs),namely oxalic,citric,and malic acids.Consequently,the physico-chemical parameters (p H and electric conductivity),Ca,Mg,Fe,Zn,and Cu release (by atomic absorption spectroscopy,AAS),chemical changes (by Fourier transform infrared,FT-IR),and organic parameters (by fluorescence) were investigated.Metal release showed to be dependent on the SRE composition and technosol characteristics.Citric acid selectively released Ca,Mg,Zn,and Cu from technosols in a concentration-dependent manner;oxalic acid showed a significant role in the release of Mg and Fe.Under relatively high LMWOA concentrations,particulate organo-mineral complexes precipitated.Additionally,technosol weathering was seen by the dissolution of humic substances and ferriallophanes,which in turn caused metal release.However,re-precipitation of these phases showed to re-sorb metals,thus underestimating the role of LMWOAs in metal release.Therefore,the selective metal leaching was highly dependent on the SRE composition and LMWOA concentrations on one hand,and on the mineral,organic,and organo-mineral components of the technosols on the other.The understanding of such processes is crucial for proposing and implementing environmental management strategies to reduce metal leaching or for the beneficial re-usage of metals (e.g.,for agromining) from technosols.
文摘Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.
