摘要:
Accurate prediction of heavy metal accumulation in soil ecosystems is crucial for maintaining healthy soil environments and ensuring high-quality agricultural products, as well as a challenging scientific task. In this study, we constructed a dataset containing 490 sets of multidimensional environmental covariate data and proposed prediction models for heavy metal concentrations (HMC) in a soil-rice system, EL-HMC (including RF-HMC and GBM-HMC), based on Random Forest (RF) and Gradient Boosting Machine (GBM) ensemble learning (EL) techniques. To reasonably evaluate the effectiveness of each model, Multiple linear and Bayesian regressions were selected as benchmark models (BM), and mean absolute error (MAE), root mean square error (RMSE), and determination coefficient R(2) were selected as evaluation indicators. In addition, sensitivity and spatial autocorrelation (SAC) analyses were used to examine the robustness of the model. The results showed that the R(2) values of RF-HMC and GBM-HMC for modeling available cadmium (Cd) concentrations in soil were 0.654 and 0.690, respectively, with an average increase of 48.0% compared to the BMs. The R(2) values of RF-HMC and GBM-HMC for predicting Cd, lead (Pb), chromium (Cr), and mercury (Hg) concentrations in rice ranged from 0.618 to 0.824 and 0.645 to 0.850, respectively, with an average increase of 58.2% compared with the BMs. The corresponding MAEs and RMSEs of RF-HMC and GBM-HMC had low error levels. Sensitivity analysis of the input features and the SAC of the prediction bias showed that the EL-HMC models have excellent robustness. Therefore, the EL technology-based prediction models for HMCs proposed herein are practical and feasible, demonstrating better accuracy and stability than the traditional model. This study verifies the application potential of EL technology in pollution ecology and provides a new perspective and solution for sustainable management and precise prevention of heavy metal pollution in farmland soil at the regional scale.
摘要:
Understanding the intricate interplay between Cd accumulation in plants and their rhizosphere micro-characteristics is important for the selection of plant species with profitable Cd phytoextraction and soil remediation efficiencies. This study investigated the differences in rhizosphere micro-ecological characteristics and Cd accumulation in chicory, Ixeris polycephala, sunflower, and Sedum alfredii in low-moderate Cd-contaminated soil. Data reveal that the dominant organic acids in rhizosphere soil that responded to Cd were oxalic and lactic acids in chicory and Ixeris polycephala, tartaric acid in sunflower, and succinic acid in Sedum alfredii. These unique organic acids could also influence the abundance of specific rhizobacterial communities in rhizosphere soil that were Sphingomonadaceae and Bradyrhizobiaceae in both Sedum alfredii (9.75 % and 2.56 %, respectively) and chicory (8.98 % and 2.82 %, respectively) rhizosphere soil, Xanthomonadaceae in both Sedum alfredii and Ixeris polycephala rhizosphere soil, and Gaiellaceae in chicory rhizosphere soil. In this case, the combined effects of the organic acids and unique rhizobacterial communities by plant species increased the bioavailable concentration of Cd in Sedum alfredii, Ixeris polycephala, and sunflower rhizosphere soil, while decreasing the Cd-DOM concentrations in chicory rhizosphere soil and the water-extractable Cd reduced by 88.02 % compared to the control. Though the capacity for Cd accumulation in the shoots of chicory was weaker than of Sedum alfredii but better than either Ixeris polycephala or sunflower, chicory presented better Cd translocation and harbored Cd mainly as the low toxic chemical form of pectates and proteins-bound Cd and Cd oxalate in its shoot. Generally, chicory, as an economic plant, is suitable for phytoremediation of low-moderate Cd-contaminated soil after Sedum alfredii.
摘要:
Soil microbial communities play essential roles in degraded soil ecosystems. The “emergent trait” indices (e.g., microbial biomass C and N, and enzyme activity) and specific soil microbiota associations have been intensively studied, but the responses of soil microbial composition and network complexities to land-use changes remain unclear. Using amplicon sequencing of 16S rRNA genes and internal transcribed spacer (ITS) regions, we assessed the response ratio of soil microbial genomic diversity, community structure, and network parameters to primary evergreen broadleaved forest (control) conversion to conifer plantations, orchards, sloping tillage, and paddy fields. Agricultural lands had a higher soil bacterial and lower fungal diversity than primary forest. Overall, primary forest conversion reduced microbial network complexity, except in the sloping tillage. Moreover, land-use changes shifted the microbial community composition by either decreasing or increasing the relative abundance of dominant and putative keystone associations. The mean response ratio (indicator response percentage to primary forest conversion) of the microbial index to the land-use change varied depending on the soil microbial alpha diversity, network topological parameters, and dominant and putative keystone associations. Alterations in soil microbial diversity, composition, and network complexity were related to reduced soil resource availability following land-use change. Our study suggested that primary forest conversion to agricultural lands did not always negatively influences soil microbial diversity, composition, network complexity, and putative keystone associations. In addition, specific soil microbial associations showed highly sensitive to land-use change.
摘要:
Remediation of CdAs co-contaminated soils has long been considered a difficult problem to solve, as Cd and As have distinctly different metallic characters. Amending contaminated soils with traditional single passivation materials may not always work well in the stabilization of both Cd and As. Here, we reported that analog soil organo-ferrihydrite composites made with either living or non-living organics (bacterial cells or humic acid) could achieve stabilization of both Cd and As in contaminated soils. BCR and Wenzel sequential extractions showed that organo-ferrihydrite, particularly at 1wt% loading, shifted liable Cd and As to more stable phases. Organo-ferrihydrite amendments significantly (p<0.05) increased soil urease, alkaline phosphatase and catalase enzyme activities. With organo-ferrihydrite amendments, the bioavailable fraction of Cd decreased to 35.3% compared with the control (65.1%), while the bioavailable As declined from 29.4% to 12.4%. Soil pH, microbial community abundance and diversity were almost unaffected by organo-ferrihydrite. Ferrihydrite and organo fractions both contributed to direct Cd-binding, while the organo fraction probably maintained the Fe-bound As via lowering ferrihydrite phase transformation. Compared to pure ferrihydrite, organo-ferrihydrite composites performed better not only in reducing liable Cd and As, but also in maintaining soil quality and ecosystem functions. This study demonstrates the applications of organo-ferrihydrite composites in eco-friendly remediation of CdAs contaminated soils, and provides a new direction in selecting appropriate soil amendments.
通讯机构:
[Huilin Yang; Zinan Luo; Dengwang Liu] C;College of Resources and Environment, Hunan Agriculture University, Changsha, Hunan, China<&wdkj&>College of Agriculture, Hunan Agricultural University, Changsha, Hunan, China<&wdkj&>Arid Land Crop Research Institute, Hunan Agricultural University, Changsha, Hunan, China<&wdkj&>College of Agriculture, Hunan Agricultural University, Changsha, Hunan, China<&wdkj&>Arid Land Crop Research Institute, Hunan Agricultural University, Changsha, Hunan, China
摘要:
Peanut is vulnerable under waterlogging stress, and it is important to explore efficient agronomic practices to reduce adverse effects induced by waterlogging stress. In this study, the effects of waterlogging stress on plant morphology, physiological and biochemical characters in peanut seedlings were studied. It was founded waterlogging stress posted adverse effects on plant growth and development and triggered the activities of antioxidant enzymes and osmotic adjustment substances to improve the plant tolerance under stress. It was also found that exogenous calcium fertilization could significantly improved root growth and development under stress. Moreover, higher dose of calcium fertilizer (1600 mg/kg) showed better performance on improving waterlogging tolerance than lower dose one (800 mg/kg) in peanut seedlings. This study explored positive effects of exogenous calcium on recovering damages especially in roots caused by waterlogging stress, providing a theoretical guidance in agronomic practice to improve waterlogging tolerance, and laying a foundation for agronomic practice when further discovering molecular mechanisms in response to waterlogging stress.
摘要:
Cadmium (Cd) is one of the dominant metal pollutants present in the aquatic environment that affects ion homeostasis, oxidative stress (OS) and immune responses of aquatic organisms. Given the physicochemical similarities between Cd(2+) and calcium (Ca(2+)) ions, their antagonism may facilitate the mitigation of Cd-induced toxicity. To better understand the role of Ca in protecting against Cd-induced toxicity in teleosts, juvenile grass carp were exposed to Cd (measured concentration 3μg/L) and a gradient of Ca concentrations (measured concentration 1.5mg/L, 2.5mg/L, 3.0mg/L, and 3.5mg/L in the control (CTL) group, low calcium (LCA) group, medium calcium (MCA) group, and high calcium (HCA) group, respectively) for 30 days. Inductively coupled plasma mass spectrometry (ICP-MS) data analyses showed that simultaneous exposure to Ca impaired the accumulation of Cd in all tested tissues. Besides, Ca addition maintained the plasma ion (Na(+), K(+), Cl(-)) homeostasis, alleviated Cd-induced oxidative stress (OS), and regulated the activities and transcriptional levels of ATPase. Furthermore, transcriptional heatmap analysis demonstrated that several indicator genes for OS and calcium signaling pathway were found to be significantly modulated by Ca addition. This work delineates a protective effect of Ca against Cd-induced toxicity in grass carp, providing new insight into the possible solutions to Cd pollution issues in aquaculture industry.
摘要:
Cadmium (Cd) pollution in agricultural soils has been a worldwide problem that threatens eco-environmental sustainability and exerts a negative influence on plant growth. The effects of nitrification inhibitors (NIs)—namely, dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP)—on Cd phytoavailability have been reported in some studies, but the underlying mechanisms driving the changes in Cd uptake and accumulation in rice (Oryza sativa L.) seedlings are not well understood. Here, rice seedlings were transplanted into Cd-contaminated paddy soil, treated with urea and NIs (DCD or DMPP), and cultivated for 21days. Pot experiments showed that NIs treatments significantly inhibited the ammoxidation process and increased the rhizospheric pH, thereby reducing the DTPA-extracted Cd concentration in soil and decreasing Cd accumulation in rice tissues. Besides, hydroponic culture experiments were performed to explore the impacts of NIs on Cd uptake and translocation in rice seedlings and identify the underlying mechanisms. It was found that adding urea combined with NIs weakened Cd uptake by rice roots through supplying a large amount of NH4+. Furthermore, NIs applications significantly limited net Cd2+ influx and down-regulated the transcription of Cd uptake-related genes in roots via increasing NH4+, thereby decreasing the movement of Cd2+ into roots and Cd accumulation in rice. However, DMPP treatments also promoted Cd root-to-shoot translocation, likely due to the DMPP-induced increase in the expression of the OsHMA2 and OsNRAMP1 genes. Our results suggested that the application of appropriate ratios of NIs and nitrogen fertilizer can inhibit Cd uptake and accumulation in rice. • Cd accumulation in rice was driven by multiple factors through NIs application. • Cd uptake in rice was mainly affected by NIs altering soil pH and Cd availability. • N forms was also regulated by NIs thus influencing Cd uptake in rice. • Urea + DMPP inhibited the expressions of NRAMP5 in rice roots. • Urea + DMPP elevated Cd translocation by promoting the HMA2 and NRAMP1 transcription.
通讯机构:
[Si Luo] C;College of Resources and Environment, Hunan Agricultural University, Changsha, People’s Republic of China
关键词:
Cadmium and arsenic;Straw return;Soil;Speciation;Bioavailability;Bacterial community
摘要:
PurposeStraw return is a common agronomic practice for improving soil fertility and sustaining crop productivity. This paper considers the potential impacts of contaminated straw return on the availability of metal(loid)s and on microbial activity in paddy soils. MethodsCadmium (Cd) and arsenic (As) co-contaminated soils were collected and incorporated with contaminated rice straw (RS) or coupled with straw-decomposing microbial inoculants (SD), and were incubated for 75 days under laboratory-controlled conditions. ResultsThe results showed that addition of straws (both RS and SD) increased soil total Cd and As concentrations by 0.07-0.11 and 1.83-1.89 mg & BULL;kg(-1), respectively. In contrast to the control treatment (no straws, CK), RS and SD treatments significantly increased soil-available As concentrations throughout the incubation period, whereas available Cd concentrations decreased from day 10 to day 45. A remarkable rise in all Cd fractions was observed in the straw-applied treatments compared with CK. The easily soluble, Ca-associated and residual fractions of As were decreased and changed into Al-associated and Fe-oxyhydroxides As fractions. Compared with RS treatment, applying SDMIs accelerated the decomposition process of the straw and the transformation of Cd and As, and increased the richness and diversity of the bacterial community. Based on redundancy analysis, pH and dissolved organic carbon (DOC) were identified as the most important controlling factors for redistribution of Cd and As fractions during straw decomposition. ConclusionsThese results highlight that we should be cautious when returning co-contaminated rice straw to paddy fields, as this practice may increase the risk of more As production. SDMI utilization is an effective strategy to immobilize Cd, but it may enhance the availability of As.
作者机构:
[Marco Race] Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, Italy;[Yaoyu Zhou] College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China;[Avelino Núñez-Delgado] Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University Santiago de Compostela, 27002 Lugo, Spain;[Zhien Zhang] Department of Chemical and Biomedical Engineering, West Virginia University, Morgantown, WV 26506, USA;[Mario Coccia] Research Institute on Sustainable Economic Growth, National Research Council of Italy (CNR), Turin Research Area of the CNR, 10135 Turin, Italy
通讯机构:
[Avelino Núñez-Delgado] D;Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University Santiago de Compostela, 27002 Lugo, Spain
摘要:
With the Topic “New Research on Detection and Removal of Emerging Pollutants” (https://www [...]
摘要:
Dissolved organic matter (DOM) can clearly reflect composting components changes, thus it is supposed to indicate the humification process during composting. To demonstrate this, three compost mixtures and two techniques were arranged. DOM evolution was detected by three spectral techniques. X-ray diffraction (XRD) showed that the crystal structure substances decreased gradually during the composting, including cellulose, struvite, sylvine, quartz, and calcite; Specifically, the struvite was found, which was conducive to the fixation of nitrogen and phosphorus. Fourier transform infrared spectroscopy (FTIR) and three-dimensional fluorescence spectroscopy (3D-EEM) further showed that pig manure-based mixtures, added cabbage, and windrow composting are beneficial to sugar, protein, fulvic acid, and soluble microbial by-products decompose and humic acids produce. This process was closely related to the change of physical-chemical parameters (temperature; pH; moisture content; and NH4+-N content) and maturity index (C/N ratio, E4/E6 and GI). Therefore, DOM evolution could quickly reflect the maturity process of compost. In subsequent research, the quantitative analysis of DOM components can be considered to modify DOM spectral parameters, or to build a model, so as to achieve rapid evaluation of compost maturity.
摘要:
Identifying suitable plants for phytoremediation of Cd (cadmium) contaminated agricultural soil is critical. In this study, whether chicory (Cichorium intybus L.) qualified as an ideal accumulator for phytoremediation was investigated. The hydroponic and pot experiments showed that Cd concentration in chicory leaves exceeded 100mgkg(-1) (BCF >1, TF >1) with 40mgkg(-1) Cd in pot; No significant effects on chicory growth, leaf protein and physiological and biochemical aspects when treated with ≤20μM or 40mgkg(-1) Cd, because chicory could relieve Cd toxicity by increasing activities of photoprotection mechanisms, the reactive oxygen species scavenging system and concentrations of functional groups in plant tissues. In field experiment, 16.2 and 26.6t ha(-1) of chicory leaves was harvested in winter and summer, respectively. The highest Cd concentration in leaves was close to 25.0mgkg(-1) (BCF >1, TF >1) from the acid soil with 0.980mgkg(-1) Cd. Over 320gha(-1) Cd was extracted from soil by harvesting chicory leaves both in winter and summer, with 9.24% and 12.9% of theoretical phytoremediation efficiency. Therefore, chicory can be as an ideal Cd-accumulator for phytoremediation of slight-to-moderate Cd-contaminated agricultural soil in any season.
通讯机构:
[Hui Fu] E;Ecology Department, College of Resources & Environments, Hunan Provincial Key Laboratory of Rural Ecosystem Health in Dongting Lake Area, Hunan Agricultural University, Changsha, People’s Republic of China
摘要:
Functional traits of individuals and not just species can regulate ecological interactions with biotic and abiotic environments, yet how individual-level functional diversity (FDind) mediates the environmental effects on community properties (e.g., interaction patterns, connectivity and productivity) remains largely unexplored. Here, we assembled 4432 individuals from 30 macrophyte species across 26 lakes in south China and measured six functional traits -shoot height, specific leaf area, lamina thickness, leaf dry mass content, stem diameter and stem dry mass content-for each individual. We estimated FDind for macrophyte community in each plot using trait probability density framework. Path analysis revealed that functional richness promoted negative interactions (the absolute value of negative: positive cohesion as proxy of community interaction patterns) and thus community productivity at lower total phosphorus (TP) and shallower water, while functional divergence/redundancy reduced negative interaction and thus community productivity at shallower water, lower TP and higher altitude. Functional evenness decreased community productivity at higher TP and deeper water. Functional dissimilarity reduced community connectivity (total cohesion) and thus community productivity at deeper water and higher altitude. Our results highlight that FDind could modify the environmental effects (from local to regional) on the interaction patterns, network connectivity and productivity of macrophyte community.
通讯机构:
[Yaocheng Deng] C;College of Resources & Environment, Hunan Agricultural University, Changsha, China
摘要:
1. The main criticism of Filella (2022) against us is that we confuse the types of organic germanium and the lack of a clear definition and discussion of organic germanium. Earlier in the discussio...