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Long-term deposition of atmospheric pollutants emitted from coal combustion and their effects on the eco-environment have been extensively studied around coal-fired power plants. However, the effects of coal-fired power plants on soil microbial communities have received little attention through atmospheric pollutant deposition and coal-stacking. Here, we collected the samples of power plant soils (PS), coal-stacking soils (CSS) and agricultural soils (AS) around three coal-fired power plants and background control soils (BG) in Huainan, a typical mineral resource-based city in East China, and investigated the microbial diversity and community structures through a high-throughput sequencing technique. Coal-stacking significantly increased (p < 0.05) the contents of total carbon, total nitrogen, total sulfur and Mo in the soils, whereas the deposition of atmospheric pollutants enhanced the levels of V, Cu, Zn and Pb. Proteobacteria, Actinobacteria, Thaumarchaeota, Thermoplasmata, Ascomycota and Basidiomycota were the dominant taxa in all soils. The bacterial community showed significant differences (p < 0.05) among PS, CSS, AS and BG, whereas archaeal and fungal communities showed significant differences (p < 0.01) according to soil samples around three coal-fired power plants. The predominant environmental variables affecting soil bacterial, archaeal and fungal communities were Mo-TN-TS, Cu-V-Mo, and organic matter (OM)-Mo, respectively. Certain soil microbial genera were closely related to multiple key factors associated with stacking coal and heavy metal deposition from power plants. This study provided useful insight into better understanding of the relationships between soil microbial communities and long-term disturbances from coal-fired power plants. [Display omitted] [ABSTRACT FROM AUTHOR]

Spartina alterniflora, an invasive plant widely distributed in China's coastal regions, has had a significant impact on the stability of wetland ecosystems and elemental biogeochemical cycles. The invasion of S. alterniflora has been found to lead to the accumulation of sulfides in the soil. The cycling of sulfur and iron in the soil is closely interconnected. Coastal estuarine wetlands are influenced by both freshwater in rivers and seawater tides, as well as the frequent variations in redox conditions caused by tidal fluctuations, which makes the cycling of sulfur and iron in the soil invaded by S. alterniflora more intricate. In this study, field surveys and laboratory experiments were conducted to explore the effects of S. alterniflora invasion and hydrological changes on the cycling of sulfur and iron as well as related functional microorganisms in the soil. The invasion of S. alterniflora showed an increase in soil reduced inorganic sulfur (RIS) components in both high and low marshes of Jiuduansha wetland, with higher content observed in summer and autumn. The tidal simulation experiments revealed abundant sulfate in seawater tidal conditions could promote the formation of acid volatile sulfides (AVS) in the soil of low marshes invaded by S. alterniflora and ensuring the continuous increase in AVS content. Diffusive gradients in-thin-films (DGT) technology indicated the existence of high-concentration soluble S2− enrichment zones in the soil of low marshes invaded by S. alterniflora, which may be related to S. alterniflora root exudates. Tidal action increased the relative abundance of sulfur-reducing bacteria (SRB) in the soil of low marshes, and under the influence of seawater tidal action, SRB exhibited higher relative abundance. However, S. alterniflora might inhibit the activity of iron-reducing bacteria (FeRB) in the soil of low marshes. In conclusion, S. alterniflora may enhance the sulfate reduction rate and promote the formation of free sulfides in tidal salt marsh ecosystems by releasing root exudates that stimulate the activity of SRB, while concurrently inhibiting the activity of FeRB and reducing their competition with SRB. This effect is particularly pronounced in low marshes under seawater tidal conditions. Thus, S. alterniflora is capable of rapidly invading tidal salt marshes by utilizing sulfides effectively. [ABSTRACT FROM AUTHOR]

Purpose: The extensive invasion of Spartina alterniflora in coastal wetlands of China has posed a ruinous risk to biodiversity and ecosystem constancy. Sulfur is an essential nutrient, while sulfide is biologically toxic and could couple with iron. The influence of S. alterniflora invasion on sulfur and iron cycling in sediment remains poorly understood. Hence, the purpose of this study is to investigate how the invasion of S. alterniflora affects the sulfur and iron cycles in sediments in coastal wetlands. Methods: Field investigations were conducted in the Jiuduansha Wetland to examine the different sulfur and iron components, microbial communities, and functional genes related to the sulfur cycle in soils colonized by S. alterniflora and in native coenosis. Results: The invasion of S. alterniflora caused the accumulation of reduced inorganic sulfur (RIS) in the sediments, and the RIS components were stratified at different sediment depths. The activity of S. alterniflora roots and the presence of low-elevation tides promoted sulfate reduction and the accumulation of acid volatile sulfide (AVS), primarily through abiotic chemical processes. These processes facilitated the invasion and expansion of S. alterniflora. Meanwhile, S. alterniflora could promote sulfate reduction by altering sediment physicochemical properties, such as pH. However, the correlation between RIS components and salinity or Eh in the low-intertidal zones was not significant due to the influence of tidal action. Nevertheless, S. alterniflora could buffer sulfide by enriching Fe, rapidly reducing Fe(III) and forming pyrite, thus mitigating sulfide stress. Conclusion: The invasion of S. alterniflora in tidal environments increased sediment sulfide levels, while S. alterniflora is able to mitigate the effects of sulfide stress on itself by efficiently utilizing iron. [ABSTRACT FROM AUTHOR]

The sulfur biogeochemical cycle controls the sulfur dynamics in the soil. In contrast to almost all deposited sulfur leaching out in temperate catchments, approximately 80% of the deposited S is retained in the catchments in subtropical regions. However, the mechanisms for sulfur retention were unclear, hindering the understanding of potential threats of legacy sulfur with environmental changes. Here, we demonstrated that sulfate reduction (as sulfide fixed in soil) was a prominent yet overlooked mechanism for sulfur retention in addition to the widely recognized sulfate adsorption in soil, based on a study on soil sulfur storage and stable isotope signatures within entire soil profiles in a typical subtropical catchment in China. Using a dual‐isotopic model, the sulfate reduction flux was further determined to be 30% of the S deposition. Due to a lot of deposited sulfur fixed via sulfate reduction, the release of soil legacy sulfur would be less in response to decreasing sulfur deposition compared to the projections only considering adsorption. However, the remobilization of large amounts of reduced S should be regarded as a threat to the environment under climate change in the future. Plain Language Summary: Sulfur budget in catchments reveals substantial retention of around 80% of deposited sulfur in subtropical soils, mitigating acidification arising from heightened sulfur deposition. The substantial sulfur retention was previously ascribed to sulfate adsorption. However, our study unveils sulfate reduction as a prominent yet overlooked retention mechanism, evidenced by soil sulfur storage estimates and stable isotope signatures across complete soil profiles in a typical subtropical Chinese catchment. Sulfate adsorption displays reversibility with declining atmospheric deposition. However, sulfate reduction exhibits relatively stable except during periods of frequent drought attributed to climate change or the soil excavation induced by land‐use change. Key Points: A dual isotopic mass balance model was built to quantify the transformations of S in the ecosystemsSulfur retention accounted for approximately 80% of deposition based on the sulfur input–output budgets for 17 sites in subtropical ChinaSulfate reduction was a prominent mechanism for sulfur retention in addition to widely recognized sulfate adsorption [ABSTRACT FROM AUTHOR]

The sulfur (S) cycle is one of the geochemical element cycles in which microorganisms play a key driving role. The microbial function of soil S cycling in response to desert degradation, however, remains largely unknown. We used metagenomics to analyze the characteristics of microbial communities and their functional genes involved in the S cycles under natural water gradients with three typical halophytes shrubs in the Ebinur Lake basin Desert, China. Our results showed that the rhizosphere effect, water gradient, and halophyte type played a major role in shaping the S cycle. On the whole, in the rhizosphere type and low water environment, the functional genes involved in the S cycle had high abundance, and the sulfur oxidizing protein (SOX) system in Alhagi sparsifolia had a high expression level. In the S cycle network structure, as the soil water content decreased, the complexity in S gene networks increased, showing the characteristics of clustering and high connectivity. Indicates the strengthening mode in microbial interactions with the water content. Interestingly, the negative correlation of the network changed with the water content, and there was more competition among communities under the low water gradient and more cooperation under the high water gradient. Through the correlation between environmental factors and the network, nitrate (NO3−) and soil available S (AS) constrained most S gene ecology networks. The key species involved in the S cycle were halophilic microorganisms. These results can enhance the understanding of soil S biogeochemical processes and contribute to the mitigation of desertification by improving soil conservation. [ABSTRACT FROM AUTHOR]

Sulfur is an essential functional element in leaves, and it plays important roles in regulating plant growth, development and abiotic stress resistance in natural communities. However, there has been limited information on the spatial variation in leaf sulfur content (LSC) and adaptive characters on a large community scale. Sulfur in leaves of 2207 plant species from 80 widespread ecosystems (31 forests, 38 grasslands and 11 deserts) in China was measured. One-way analysis of variance with Duncan's multiple-range tests were used to evaluate the differences in LSC among different plant growth forms and ecosystems. We fitted the relationships of LSC to spatial and climate factors using regression. Structural equation modeling analysis and phylogenetic analysis helped us further explore the main factors of LSC variation. LSC ranged from 0.15 to 48.64 g kg–1, with an average of 2.13 ± 0.04 g kg–1 at the community scale in China. We observed significant spatial variation in LSC among different ecosystems and taxa. Overall, LSC was higher in arid areas and herbs. Furthermore, higher LSC was observed under environments of drought, low temperatures and intense ultraviolet radiation. Temperature, precipitation, radiation, soil sulfur content and aridity jointly regulated LSC, explaining 79% of the spatial variation. However, LSC was not significantly related to phylogeny. Our results demonstrate that LSC plays an important role in plant adaptations to extreme environments and further extend our understanding of the biological function of sulfur from the organ to the community level. These findings highlight the importance of sulfur metabolism for our understanding of the impact of global climate change on plants. [ABSTRACT FROM AUTHOR]

The microbial community structures, sulfur speciation, and their correlations in soil samples in and around Xiangtan Liejiaqiao Coal Gangue Dump in Hunan province south of China were analyzed with gene sequencing, sulfur K-edge X-ray absorption near edge structure spectroscopy (XANES), and principal components analysis (PCA). The gene sequencing results showed that the microbes in soil samples fell into six phyla, i.e., Nitrospira, Actinobacteria, Firmicutes, Proteobacteria, Deferribacteres, and Ktedonobacteria. The dominant bacteria species in the four samples were Moorella glycerini, Escherichia coli, Leptospirillum ferriphilum, Ferrimicrobium acidiphilum, Sulfobacillus benefaciens, and Desulfomonile tiedjei. According to the XANES results, sulfur speciation in soil samples was composed of sulfate, sulfite, thiosulfate, and organic sulfur. The PCA analysis among physicochemical characteristics, sulfur speciation, and distributions of microbes showed that oxidation-reduction potential (ORP) was correlated to the bacterial population of Proteobacteria, while pH was correlated to Ktedonobacteria. Furthermore, the correlation between sulfur speciation (sulfate and thiosulfate) and microbes (Deferribacteres, Nitrospira, and Actinobacteria) was particularly significant. Sulfite and glutathione also presented a strong correlation with Ktedonobacteria and Proteobacteria. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the spatial variability and the degree of abundance and deficiency of medium and micronutrient element contents in typical paddy soils of China, and to develop the best fertilization management for improving rice yields. Based on 289 monitoring points of paddy soils distributed across the northeast, Yangtze River delta, the middle of the Yangtze River, the southwest and south of China, soil samples collected in 2016 were determined for the contents of available medium and micronutrient elements (calcium, magnesium, sulfur, iron, manganese, copper, zinc, boron and molybdenum) in paddy soils. The spatial variability of these elements across the five regions was assessed. Combined with the critical values for limiting rice growth due to deficiency of available medium and micronutrient elements, the abundance and deficiency degree of available medium and micronutrient elements in the paddy soils were evaluated. The results showed that the contents of exchangeable magnesium and available boron in the northeast of China were much higher than those in the other regions, while the contents of available zinc in paddy soils were the lowest among the five regions. The highest average content of available manganese and the lowest average content of available sulfur in the paddy soils were both found in Yangtze River delta. The highest average content of available copper but the lowest average content of available iron, manganese and molybdenum among paddy soils was observed in middle of the Yangtze River. As compared with the other areas, the exchangeable calcium content of the paddy soils in the southwest of China was significantly higher (P<0.05), while the available copper content was significantly lower (P<0.05). Compared with the other areas, the contents of available iron and molybdenum in the south of China were significantly higher (P<0.05), while the contents of exchangeable calcium and magnesium were significantly lower (P<0.05). Critical values for evaluation of these elements were summarized based on practices and previous studies. The critical values for exchangeable calcium, exchangeable magnesium and available sulfur were 400, 50 and 16 mg/kg, respectively. The critical values for available iron, manganese, copper, zinc, boron and molybdenum were 4.5, 10, 2, 1.5, 0.5 and 0.15 mg/kg, respectively. The soils would be lack of the corresponding element if the contents of these elements were below the critical values and thereby the rice growth may be limited. Based on the critical values, the exchangeable calcium and magnesium contents in paddy soils of the five regions were rich in China. The contents of available sulfur in paddy soils were abundance for rice growth in the northeast, the middle of the Yangtze River, and the southwest of China, while 42.2% and 41.8% of monitoring points in Yangtze River delta and south of China were lack of available sulfur. The contents of available iron, manganese and copper were abundance in all the paddy soils. The proportions of monitoring points with lower contents of available zinc than its critical value were 75.0%, 52.3%, 31.9%, 53.2% and 10.4% in the northeast, Yangtze river delta, the middle of the Yangtze River, the southwest, and south of China, respectively. The proportions of monitoring points with lower contents of available boron than its critical value were 38.5%, 65.2%, 92.2%, 88.6% and 78.3% in the northeast, Yangtze river delta, the middle of the Yangtze River, the southwest, and south of China, respectively. The proportions of monitoring points with lower contents of available molybdenum than its critical value were 28.6%, 60.4%, 82.6%, 42.0% and 33.4% in the northeast, Yangtze river delta, the middle of the Yangtze River, the southwest, and south of China, respectively. It indicated that the contents of calcium, magnesium, iron, manganese and copper in the paddy soils of typical areas in China were abundance for rice growth. Sulfur fertilizer was needed in some areas of Yangtze River delta and southwest of China. The available zinc, boron and molybdenum in most of paddy soils were deficiency, and additional micronutrient element fertilizers were needed for rice growth, especially for zinc in the northeast, zinc, boron and molybdenum in Yangtze River delta, boron and molybdenum in middle of the Yangtze River, boron in southwest, and boron in south of China. And the medium and micronutrient element fertilizers should be included as part of fertilization management in practice for improving rice yields. [ABSTRACT FROM AUTHOR]

Soil communities are intricately linked to ecosystem functioning, and a predictive understanding of how communities assemble in response to environmental change is of great ecological importance. Little is known about the assembly processes governing abundant and rare fungal communities across agro‐ecosystems, particularly with regard to their environmental adaptation. By considering abundant and rare taxa, we tested the environmental thresholds and phylogenetic signals for ecological preferences of fungal communities across complex environmental gradients to reflect their environmental adaptation, and explored the factors influencing their assembly based on the large‐scale soil survey in agricultural fields across eastern China. We found that the abundant taxa exhibited remarkably broader response thresholds and stronger phylogenetic signals for the ecological preferences across environmental gradients compared to the rare taxa. Neutral processes played a key role in shaping the abundant subcommunity compared to the rare subcommunity. Null model analysis revealed that the abundant subcommunity was less clustered phylogenetically and governed primarily by dispersal limitation, while homogeneous selection was the major assembly process in the rare subcommunity. Soil available sulfur was the major factor mediating the balance between stochastic and deterministic processes of both the abundant and rare subcommunities, as indicated by an increase in stochasticity with higher available sulfur concentration. Based on macroecological spatial scale datasets, our study revealed the potential broader environmental adaptation of abundant fungal taxa compared to rare fungal taxa, and identified the factors mediating their distinct community assembly processes in agricultural fields. These results contribute to our understanding of the mechanisms underlying the generation and maintenance of fungal diversity in response to global environmental change. [ABSTRACT FROM AUTHOR]

• Continuous tracking for soil sulfur storage with a maximum of 13 years based on the invasion time of exotic Spartina alterniflora. • Changes for soil sulfur storage in different seasons with the invasion of Spartina alterniflora. • Varieties for soil sulfur storage in different depths. • Compared with the soil sulfur storage between exotic Spartina alterniflora , native species S. mariqueter and unvegetated mudflats. • Explored the relationships between sulfur and environmental factors. With an aim to determine whether Spartina alterniflora actively changes the habitat environment, thus facilitating its successful competition over native species, a field experiment was carried out at the Jiuduansha Wetland National Nature Reserve. Sulfur concentrations in the soil sediments were compared among wetlands dominated by the exotic Spartina alterniflora , the co-occurring native species S. mariqueter and unvegetated mudflat. The results show that the soil sulfur concentrations in the Spartina alterniflora community showed significant spatiotemporal variability with the years since invasion. The S. alterniflora community contained the highest concentrations of sulfur in the soil sediment. Moreover, the sulfur concentrations were higher in the initial invasion area than at the edges of the invading area. The was little difference in soil sulfur concentrations between communities containing native species S. mariqueter and unvegetated mudflat. There were significant correlations between soil sulfur concentrations and carbon and nitrogen concentrations; the soil nitrogen concentrations were negatively correlated with the sulfur concentrations, and the carbon concentrations were positively correlated with the sulfur concentrations. In different seasons, the concentration of sulfur is relatively higher in spring than which in other seasons. Furthermore, the sulfur concentrations at different soil depths also exhibited significant changes with depths. In addition, the soil sulfur concentrations associated with S. alterniflora also showed a trend of increasing first and then decreasing with depth, the soil sulfur concentrations in S. alterniflora soils were obviously higher than those in the S. mariqueter community and unvegetated mudflat, the maximum concentrations in S. alterniflora soils occurred at the depth of 40–60 cm. The findings of this study indicate that S. alterniflora increases wetland sulfur storage, which may explain the mechanism of expansion of S. alterniflora in the Jiuduansha Wetland. [ABSTRACT FROM AUTHOR]

Sulfur (S) availability plays a vital role in driving functions of terrestrial ecosystems, which can be largely affected by soil inorganic S fractions and pool size. Enhanced nitrogen (N) input can significantly affect soil S availability, but it still remains largely unknown if the N effect varies with frequency of N addition and mowing management in grasslands. To investigate changes in the soil S pool and inorganic S fractions (soluble S, adsorbed S, available S, and insoluble S), we conducted a field experiment with different frequencies (two times per year vs. monthly additions per year) and intensities (i.e., 0, 1, 2, 3, 5, 10, 15, 20, and 50 g N m -2 yr -1) of NH4NO3 addition and mowing (unmown vs. mown) over 6 years in a temperate grassland of northern China. Generally, N addition frequency, N intensity, and mowing significantly interacted with each other to affect most of the inorganic S fractions. Specifically, a significant increase in soluble S was only found at high N frequency with the increasing intensity of N addition. Increasing N addition intensity enhanced adsorbed S and available S concentrations at low N frequency in unmown plots; however, both fractions were significantly increased with N intensity at both N frequencies in mown plots. The high frequency of N addition increased the concentrations of adsorbed S and available S in comparison to the low frequency of N addition only in mown plots. Changes in soil S fractions were mainly related to soil pH, N availability, soil organic carbon (SOC), and plant S uptake. Our results suggested that N input could temporarily replenish soil-available S by promoting dissolution of soil-insoluble S with decreasing soil pH and mineralization of organic S due to increasing plant S uptake. However, the significant decrease in organic S and total S concentrations with N addition intensity in mown plots indicated that N addition together with biomass removal would eventually cause soil S depletion in this temperate grassland in the long term. Our results further indicated that using large and infrequent N additions to simulate N deposition can overestimate the main effects of N deposition and mowing management on soil S availability in semiarid grasslands. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flow-sediment regulation can enhance soil net sulfur mineralization rate (R NSM). • Higher R NSM values were observed in the seasonal flooding wetlands. • Soil properties in three wetlands were changed during flow-sediment regulation. • Both Aryl and MBN showed different seasonal fluctuations in three wetland soils. • Soil EC and microbial activity significantly affected R NSM in three wetlands. Soil organic sulfur mineralization can provide absorbable sulfate for plants. However, little is known about the influencing mechanisms of hydrological conditions on soil organic sulfur mineralization in coastal wetlands. Here, an in-situ incubation experiment was conducted to identify the seasonal characteristics of organic sulfur mineralization rates (R NSM) from April to October in surface soils in the seasonal flooding wetlands (SEW), the short-term flooding wetlands (SHW) and the tidal flooding wetlands (TIW) affected by flow-sediment regulation. The results showed lower electrical conductivity (EC) and sand contents and higher water content, and silt and clay contents in SEW, SHW and TIW soils after flow-sediment regulation. The dehydrogenase enzyme activity values in three wetland soils increased from May to August and then decreased after August. Generally, the microbial biomass carbon levels in three wetland soils decreased firstly from May to June and then increased from June to September. However, both arylsulfatase enzyme activity and microbial biomass nitrogen showed different seasonal fluctuations in three wetland soils. The R NSM values in three wetland soils were obviously enhanced during the regulation, but higher R NSM values were observed in SEW soils. Soil properties such as EC and microbial activity were the main factors influencing the R NSM values in these wetland soils. These findings of this study can provide an in-deep understanding of organic sulfur mineralization in wetland soils of the ecotone formed by the interaction between freshwater and seawater in the large river deltas. [ABSTRACT FROM AUTHOR]

Limited information existed about the transformation of sulfur (S) in black soil in northeast China, and its benefit to maize. The objectives of this study were to characterize the S forms in black soil, to correlate the content of various S forms in soil with maize S uptake, and reveal the availability of different S forms to maize based on two pot experiments. One group of soil samples was collected from farmlands in three representative black soil sites: Gongzhuling, Hailun, and Bei'an in northeast China, and another group of soil samples, including no fertilization (CK), manure (M), chemical fertilizers (NPK), chemical fertilizers plus manure (MNPK), was collected from the Black Soil Ecological Experiment Station, Heilongjiang Academy of Sciences, Harbin, Heilongjiang Province. The results showed that maize S uptake was correlated with the content of water-soluble sulfur (H2O-S), organic S (Org-S), and available S (Avai-S). Maize S uptake gradually decreased during three maize growing periods in all soils when no S fertilizer was applied, and the largest decrease was observed in the third period. Maize S uptake increased under treatments that received S fertilizer and decreased in the order of MNPK > M > NPK > CK. Total soil S content decreased in CK, NPK, and MNPK, and showed no change in M when maize was continuously planted without S fertilizer. However, soil total S content increased in response to S fertilizer, and the most when manure was applied. [ABSTRACT FROM AUTHOR]

Abstract: Several million hectares of salt-affected land in the western Songnen Plain, in northeast China, is characterized as hard saline-sodic soils because of their poor physical and chemical properties. Desulfurized gypsum, a by-product of thermal power plants for removal of sulfur from coal, may be used as an external source of Ca2+ for reclamation of saline-sodic soil in this plain because it is comparatively cheap, generally available, and has a high gypsum content (>900gkg−1). In the present study, the effects of desulfurized gypsum on physical and chemical properties of saline-sodic soil and growth and yield of rice (Oriza sativa L.) were assessed in a soil column experiment. Desulfurized gypsum was added to the saline-sodic soil (ECe =26.00dSm−1, SARe =397.22 (mmolc L−1)1/2, pH=10.48) at rates of 0.00gkg−1 (control), 15.00gkg−1 (100% gypsum requirement (GR) treatment) and 30.00gkg−1 (200% GR treatment). The results demonstrated that desulfurized gypsum significantly increased the wet stability of macro-aggregates (>0.25mm), the IR and the K s of the saline-sodic soil. Soil salinity (ECe), sodicity (SARe) and pH decreased to 2.72dsm−1, 8.65 (mmolc L−1)1/2, and 8.05 in the 200% GR treatment, and 4.93dsm−1, 24.74 (mmolc L−1)1/2 and 8.75 in the 100% GR treatment from 24.65dsm−1, 390.60 (mmolc L−1)1/2 and 10.28 in the control, respectively. The yield of rice (O. sativa L.) increased from 0.0gplant−1 in control to 1.83gplant−1 and 2.45gplant−1 in 100% GR treatment and 200% GR treatment, respectively. Desulfurized gypsum is an effective amendment for saline-sodic soil in the west of Songnen Plain, northeast China. [Copyright &y& Elsevier]

Current (C) and previous year (C + 1) needles and soils (organic horizon, 0–10 cm and 10–20 cm mineral depth) of Masson pine ( Pinus massoniana L.) trees were sampled at four forested sites (Huang Pu industrial district, HP; South China Botanical Garden, BG; Mao Feng Mt., MF; and Nan Kun Mt., NK) in Guangzhou along a urban-rural gradient and analyzed for sulfur (S) and heavy metals (Cu, Zn, Ni, Cd, Cr and Pb) concentrations. Needle concentrations of all the elements were significantly higher at industrial HP than at other three sites, except for Cu and Pb which were highest at the traffic site (BG). The C + 1 needles generally had higher Cu, Cd, Pb, Zn, Cr than the C needles while the opposite was for Ni and S. Total and available Cd, Pb, Zn in soils peaked at the urban sites (HP and BG) and decreased at suburban MF and rural NK. Heavy metals were generally higher in the organic soils than in the mineral soils at all sites. Zinc and Pb at all sites, and Cd, S and Cu at the urban sites (HP and BG) in soils or pine needles were above or near their respective natural background levels, implying that threats resulted from these toxic elements occurred on local particularly urban forests, but did not for Cr and Ni due to their presence below their background values. Our results demonstrated that elements concentrations in needles and soils had reflected the variability of pollutants and the environmental quality change along the urban–rural transect, and were efficient as biomonitors to assess the influence of anthropogenic activities along the urbanization course on forest health. [ABSTRACT FROM AUTHOR]

It was the objective of this study to compare the suitability of different extractants for predicting the availability of sulfur (S) in natural grassland in a sulfur response trial on three different soil types in the Inner Mongolia steppe of China. For soil analysis, seven different extractants have been employed. The inorganic SO4–S concentration was determined by ion chromatography. Additionally, in the Ca(H2PO4)2 extract the total soluble S was determined employing turbidimetry. Weak salt solutions (0.15% CaCI2, Ca(H2PO4)2, and KH2PO4) extracted similar amounts of SO4–S. Extraction with 0.025 M KCI provided the lowest SO4–S values. Deionized water dissolved significantly more SO4–S in the control plots than most weak salt extractants. The concentration of soluble organic S decreased in the control plots after 100 days of plant growth, indicating that the organic Spool contributed significantly to the S nutrition of the forage crops. Significant relationships among the SO4–S in the soil determined in different extracts and crop yield, sulfur content in the forage, and total sulfur uptake were only found for the Ca(H2PO4)2 extract. In general, the correlation coefficients proved to be unsatisfactory for field experimentation. [ABSTRACT FROM AUTHOR]

Common wild rice ( Oryza rufipogon Griff.), known as the ancestor of Asian cultivated rice ( Oryza sativa L.), is the most important germplasm for rice improvement. The first male sterility gene was found in the wild rice, and introduced to the cultivated rice, which launched the fast development of the high-yielding hybrid rice. Other agronomically beneficial traits in the wild rice, such as rice tungro virus resistance, bacterial leaf blight ( Xa21 gene) resistance and acid sulfate soil tolerance, have played important roles in rice breeding. China has the northernmost distribution area of wild rice possessing great genetic diversity. However, most of the populations of this species have disappeared in China over the last three decades, mainly caused by habitat loss, fragmentation and other human disturbances. Unfortunately, the decline of existing populations still continues. In the present study, we reviewed studies on genetic diversity and conservation of this wild rice in China, concentrating on population structure, pollen competition, pollen/gene flow from cultivated rice to wild rice, and ecological restoration in relation to in situ conservation. The relatively high genetic diversity of populations of O. rufipogon in China suggests that there is great value for conservation. Considerable gene flow from cultivated rice to wild rice may alter the genetic structure of natural populations of O. rufipogon and eventually lead to its genetic erosion. Pollen competition between wild and cultivated rice has caused a low rate of crop-to-wild gene flow, but it does not completely prevent gene flow from the crop. Effective isolation measures should be undertaken in the regions where in situ conservation of O. rufipogon is carried out. Reintroduction is an important alternative for the in situ conservation of wild rice species. As wild rice is an important genetic resource, both in situ and ex situ conservation strategies are needed. [ABSTRACT FROM AUTHOR]

Sulphur fractionation and availability to plants are poorly understood in calcareous soils. Sixty-four calcareous soils containing varying amounts of CaCO3 were collected from ten provinces in China and their S fractions determined. Organic S was the predominant fraction of S, accounting for on average 77% of the soil total S. The amounts of adsorbed sulphate were found to be negligible. 1 M HCl extracted substantially more sulphate than either 0.01 M CaCl2 or 0.016 M KH2PO4, indicating the existence of water-insoluble but acid-soluble sulphate, probably in the form of sulphate co-precipitated with CaCO3. The concentrations of water-insoluble sulphate correlated positively with the contents of CaCO3 and accounted for 0.03-40.3% (mean 11.7%) of soil total S. To test the bioavailability of water-insoluble sulphate, a sulphate-CaCO3 co-precipitate labelled with35S was prepared and added to a calcareous soil in a pot experiment with either NHor NOas the N source. In 29 days, wheat plants took up 10.6% and 3.0% of the35S added to the soil in the NHand NOtreatments, respectively. At the end of the pot experiment, the decrease of water-insoluble, acid-soluble, sulphate was more apparent in the NHthan in the NOtreatment. The results indicate that sulphate co-precipitated with CaCO3 in calcareous soils may become partly available for plant uptake, depending on rhizosphere pH, if the field precipitate is similar to the laboratory prepared sample studied. [ABSTRACT FROM AUTHOR]

Reports on Rhodococcus erythropolis LSSE8-1, a biodesulfurization strain from the soil of Chishui gas field, Guizhou Provinces, China. Analysis of its metabolism product; Finding that the strain is a biocatalyst that can oxidize dibenothiophene (DBT) to 2-hydroxydiphenyl (HBP); Implication for the sulfur in DBT; Mention of DBTO2 (dibenzothiophene 5.5-dioxide) as substrate; Finding that DBT and HBP in the culture, which indicates the reaction from DBT to DBTO2 is reversible in the cell; Conditions that have a poisonous effect on the cell; The reason for DBTO2 accumutation in the process of biodesulfurization; How the strain's plasmid DNA is treated by lysozine and isolated by alkaline method to be used as the template of PCR reaction; Amplification of dsz gene fragments 1.3, 1.0 and 1.2 kb; Indication that each fragment is ligate with PGEM-T vector, and cloned into E. coli DH5a; Sequencing of the clone DNA, which shows dsz-related genes are highly conservative; The identities of various dsz with respect to IGTS8.

The sulphur status of four soils and 122 forage plants from the Inner Mongolia steppe was determined. The organic sulphur concentration ranged from 17 μg g–1 in the 0·2–0·4 m soil layer to 397 μg g–1 in the topsoil. The mean sulphate-S concentrations were <10 μg g–1 ; greater concentrations were found only in the chernozem soil. Biomass-S accounted for 0·018–0·028 of total S in four soils. Three-quarters of plant samples examined had <1·6 g kg–1 S, and >0·80 of them had an N:S ratio >14:1. More than 0·80 of the plants were deficient in S. There was a close relationship between plant-available soil sulphur concentrations and total plant sulphur concentrations. It was concluded that sulphur deficiency is widespread in the Inner Mongolia steppe and that sulphur fertilizer requirements should be evaluated. [ABSTRACT FROM AUTHOR]

A new soil test method for determining soil available sulfur (S) using an anion exchange resin strip, a specially pretreated anion exchange membrane encased in a plastic applicator-Plant Root Simulator Probe, was evaluated. Samples of 18 China soils were collected from the 0-20 cm layer, dried, sieved, and analyzed for available S using four chemical extracting solutions: 0.01 mol calcium chloride (CaCl[SUB2]) L[SUP-1], 0.01 mol calcium dihydrogen phosphate [Ca (H[SUB2]PO[SUB4])[SUB2] L[SUP-1], 0.016 mol potassium dihydrogen phosphate (KH[SUB2]PO[SUB4]) L[SUP-1], and 0.5 mol sodium bicarbonate (NaHCO[SUB3]) L[SUP-1] (pH 8.5). Available S in soils was also extracted by a resin strip method with 24-hour and 2-week burial times. Pot experiments were conducted to compare plant response to determined soilavailable S. Results showed that soil-available S extracted by the resin strips at 24 hour and 2 week burial times was significantly correlated with S extracted by the chemical methods, especially highly and significantly correlated with available S by 0.01 mol Ca (H[SUB2]PO[SUB4])[SUB2] L[SUP-1] (r[SUP2]=0.725*** and r[SUP2]=0.600***) and 0.016 mol KH[SUB2]PO[SUB4] L[SUP-1] (r[SUP2]=0.706*** and r[SUP2]=0.540***), respectively. Resuits also showed significant correlation between S availability by the resin strips at the two burial times and plant S uptake (r[SUP2]= 0.594***, r[SUP2]=0.401** for corn and r[SUP2]=0.773***, r[SUP2]=0.546*** for rice). Furthermore, results showed significant correlation between determined S by the resin strip at the 24 hour burial time and relative dry matter yield for corn (r[SUP2]=0.494**) and rice (0.687***), respectively. An anion exchange resin strip was found to be a suitable alternative method in the evaluation of S bioavailability in soils. [ABSTRACT FROM AUTHOR]

Anthropogenic emissions of nitrogen- (N) and sulfur (S)-containing pollutants have declined across China in recent years. However, the responses of N and S depositions and dynamics in soil remain unclear in subtropical forests. In this study, the wet and throughfall depositions of dissolved inorganic N (DIN) and SO42− were continuously monitored in a mildly polluted subtropical forest in Southeast China in 2017 and 2018. Moreover, these solutes in soil water along the soil profile were monitored in 2018. Throughfall deposition of DIN and S decreased by 59% and 53% in recent 3 years, respectively, which can be majorly attributed to the decreases in wet depositions of NO3− and SO42−. Meanwhile, NH4+ deposition remained relatively stable at this site. Even though N deposition in 2018 was below the N saturation threshold for subtropical forests, significant N leaching still occurred. Excess export of N occurred in the upper soil layer (0–15 cm), reaching 6.86 ± 1.54 kg N/ha/yr, while the deeper soil (15–30 cm) was net sink of N as 8.29 ± 1.71 kg N/ha/yr. Similarly, S was excessively exported from the upper soil with net flux of 14.7 ± 3.15 kg S/ha/yr, while up to 6.37 ± 3.18 kg S/ha/yr of S was retained in the deeper soil. The significant N and S leaching under declined depositions suggested that this site possibly underwent a transition state, recovering from historically high acid deposition. Furthermore, the rainfall intensity remarkably regulated leaching and retention of SO42− and DIN at this site. The impacts of climate changes on N and S dynamics require further long-term monitoring in subtropical forests. [ABSTRACT FROM AUTHOR]

• Soil TS, TIS and all IS fractions increased after invasion except HVS. • Conversion of sulfur state from precipitated to dissolved was promoted by invasion. • S. alterniflora improved supply capacity of sulfur and reduced its toxicity. • Effect of S. alterniflora on soil TS level tend to reinforce as latitude decrease. With immense impact on coastal ecosystems' function, especially on nutrient cycle, Spartina alterniflora has become the most importantly invasive species in coastal wetland of China. However, the alternation of sulfur level and transformation between different inorganic sulfur (IS) fractions caused by the plant are poorly understood. In order to study the effect of S. alterniflora invasion and growth on soil IS components, we used space-for-time substitution method and examined a whole year dynamics of different sulfur components in 0–60 cm soil of S. alterniflora tidal flat and mudflat at Jiaozhou Bay. Results indicated S. alterniflora improved soil sulfur level and its bio-availability, increased the contents of soil TS, total inorganic sulfur (TIS) and all of the IS fractions except hydrochloric acid volatile sulfur (HVS). But only the rate of soil adsorbed sulfur (AS) to TIS raised following invasion. In addition, S. alterniflora elevated the accumulation sites of soil Hydrochloric acid soluble sulfur (HSS) and HVS from deep soil to rhizosphere in spring. Key impact factors on IS fractions altered as invasion from soil physicochemical factors to plant fctors. Further, S. alterniflora encouraged the transformation of sulfur state from precipitation (HSS, HVS) to dissolved (HS, AS). This implies that the plant induced to an elevation of sulfur provided capacity and a reduction of sulfur toxicity in soil, which has vitally ecological significance for its expansion in costal wetlands. Now, S. alterniflora has occupied large area mudflat and was competing for habitat with native species in Jiaozhou Bay. [ABSTRACT FROM AUTHOR]

• Phosphorus fertilization decreased soil sulfur availability in two tropical forest. • Phosphorus fertilization increased resource allocation of soil microbe for sulfur demand. • Nitrogen fertilization has no effect on microbial sulfur and soil sulfur availability. • Nitrogen fertilization decreased the resource allocation of soil microbe for sulfur relative to other nutrients. • Phosphorus fertilization as forest management practice may be used more careful as sulfur deposition decreased. Understanding how phosphorus (P) and nitrogen (N) fertilization influence the dynamics of other nutrients [particularly sulfur (S)] is essential for improving the integrated nutrient management of tropical plantations. This study investigated how adding P and N fertilizers would affect S dynamics in the soils of two tropical forest plantations. Specifically, we tested whether the addition of P and N alters the availability of exchangeable S and microbial biomass S (MBS) and, hence, arylsulfatase activity (AS) and ratios of AS to C- and/or N-acquiring enzyme activity in the 0–5 cm soil layer were measured. The sites contained both control plots (no fertilizer application) and plots with 6-year continuous fertilizer (P and N) application. Soil exchangeable S clearly decreased, while AS activity marginally increased in P-fertilized plots. The ratios of soil AS activity to C- and/or N-acquiring enzyme activity tended to increase, possibly because the requirements of microbes for S relative to C and N were elevated, with P fertilization exacerbating shortages in S. In comparison, N fertilization did not influence exchangeable S, soil pH, and MBS. This lack of response might be attributed to continuous deposition of high levels of background N at the study sites. Soil AS activity and the ratios of soil AS activity to C- and/or N-acquiring enzyme activity tended to be lowered by N fertilization; thus, AS activity might be more sensitive to N fertilization than to soil pH. In conclusion, P fertilization must be carefully managed in tropical forest plantations to minimize its negative impact on soil S availability. [ABSTRACT FROM AUTHOR]