scholarly journals Influences of land reclamation on soil bacterial communities of abandoned salt pans in the Yellow River Delta

Author(s):  
Yihao Zhu ◽  
Xiliang Song ◽  
Xiaoli Liu ◽  
Weifeng Chen ◽  
Xuchang Niu ◽  
...  

Reclamation has been widely accepted to restore abandoned lands. Most studies focused on the improvement of land reclamation in soil nutrients and microbial activities. However, the effects of reclamation time on bacterial communities of abandoned salt pans are still unclear. The object of this study is to: i) assess the successional change of soil physicochemical properties and bacterial communities in reclaimed abandoned salt pans with different reclamation histories, and ii) figure out the main limit factors on the improvement of soil quality in reclaimed abandoned salt pans. The soils in a farmland (RTBL) and six abandoned salt pans with 1 year (RT1), 2 years (RT2), 3 years (RT3), 4 years (RT4), 8 years (RT8), and 9 years (RT9) of reclamation were sampled to investigate the temporal variation of soil properties, heavy metal content, bacterial community composition, and diversity. Results showed that the soil bulk density (BD), total dissolved salt (SS), median particle size (MMAD) decreased with the increase of reclamation time, while soil nutrient (soil organic matter, total nitrogen, available phosphorus, available potassium) showed an opposite trend. The bacterial α-diversity increased first, then decrease. Land reclamation enhanced the relative abundances of Acidobacteria, Chloroflexi, and Actinobacteria but reduced the relative abundances of Proteobacteria, Gemmatimonadetes, and Bacteroidetes. Compared with RTBL, the soil nutrients and bacterial community structure in RT1, RT2, RT3, and RT4 showed a significant difference.Therefore, reclamation time is a vital driving force for restoring soil physicochemical properties and bacterial communities in abandoned

2020 ◽  
Vol 112 (5) ◽  
pp. 4358-4372
Author(s):  
Meiqi Chen ◽  
Jisheng Xu ◽  
Zengqiang Li ◽  
Bingzi Zhao ◽  
Jiabao Zhang

SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 595-609
Author(s):  
Zijun Zhou ◽  
Zengqiang Li ◽  
Kun Chen ◽  
Zhaoming Chen ◽  
Xiangzhong Zeng ◽  
...  

Abstract. Conservation tillage has attracted increasing attention over recent decades, mainly due to its benefits for improving soil organic matter content and reducing soil erosion. However, the effects of long-term straw mulching under a no-till system on soil physicochemical properties and bacterial communities at different soil depths are still unclear. In this 12-year experiment of straw removal (CK) and straw mulching (SM) treatments, soil samples were collected at 0–5, 5–10, 10–20, and 20–30 cm soil depths. The results showed that the contents of organic carbon (C), nitrogen (N), and phosphorus (P) fractions, and bacterial abundance significantly decreased, whereas pH significantly increased with soil depth. Compared with CK, SM significantly increased total N, inorganic N, available P, available potassium, and soil water content at 0–5 cm, total organic C content at 0–10 cm, and dissolved organic C and N contents at 0–20 cm. Regarding bacterial communities, SM increased the relative abundances of Proteobacteria, Bacteroidetes, and Acidobacteria but reduced those of Actinobacteria, Chloroflexi, and Cyanobacteria. Bacterial Shannon diversity and Shannon's evenness at 0–5 cm were reduced by SM treatment compared to CK treatment. Furthermore, SM increased the relative abundances of some C-cycling genera (such as Terracidiphilus and Acidibacter) and N-cycling genera (such as Rhodanobacter, Rhizomicrobium, Dokdonella, Reyranella, and Luteimonas) at 0–5 cm. Principal coordinate analysis showed that the largest difference in the composition of soil bacterial communities between CK and SM occurred at 0–5 cm. Soil pH and N and organic C fractions were the major drivers shaping soil bacterial communities. Overall, SM treatment is highly recommended under a no-till system because of its benefits to soil fertility and bacterial abundance.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9612
Author(s):  
Tong Jia ◽  
Tingyan Guo ◽  
Baofeng Chai

This study analyzed Imperata cylindrica litter to determine variation in bacterial community composition and function along with enzyme activity as phytoremediation progresses. We found significant differences in physical and chemical properties of soil and litter in the different sub-dams investigated. The Actinobacteria, Gammaproteobacteria and Alphaproteobacteria were the dominant bacteria found in the litter of the different sub-dams. The alpha diversity (α-diversity) of litter bacterial community increased over as phytoremediation progressed, while total soil carbon and total litter carbon content were positively correlated to bacterial α-diversity. Total litter carbon and total nitrogen were the key factors that influenced bacterial community structure. Heavy metal can influence the degradation of litters by altering the composition of the microbial community. Furthermore, bacterial communities encoded with alpha-amylase (α-amylase) dominated during the initial phytoremediation stage; however, bacterial communities encoded with hemicellulase and peroxidase gradually dominated as phytoremediation progressed. Findings from this study provide a basis for exploring litter decomposition mechanisms in degraded ecosystems, which is critically important to understand the circulation of substances in copper tailings dams.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 954
Author(s):  
Saiyaremu Halifu ◽  
Xun Deng ◽  
Xiaoshuang Song ◽  
Yuning An ◽  
Ruiqing Song

Pinus sylvestris var. mongolica is an important tree species for ecological construction and environmental restoration owing to its rapid growth rate and excellent stress resistance. Pinus sylvestris var. mongolica sphaeropsis blight is a widespread disease caused by Sphaeropsis sapinea. This study was focused on non-infected (CK) and infected (SS) Pinus sylvestris var. mongolica plants in Zhanggutai area, Liaoning Province, China. Illumina high-throughput sequencing based on the templates of sequencing-by-synthesis working with reversible terminators is a widely used approach. In the present study, systematic differences in relationships among rhizosphere soil physicochemical properties, bacterial community structure, diverse bacterial genera, and alpha diversity indices between the two categories were evaluated. The current findings are as follows: (1) Shannon’s index of SS soil was significantly higher than CK, and it was significantly lower in May than July and September (p < 0.05). (2) Non-metric multidimensional scaling (NMDS) showed a difference in bacterial community structure during May (spring), July (summer), and September. (3) At the phylum level, no significant difference was found in the bacterial genera between CK and SS soil for three seasons; however, at the genus level, there were about 19 different bacterial genera. The correlation studies between 19 different bacterial genera and environmental factors and α-diversity indicated that bacterial genera of non-infected and infected Pinus sylvestris var. mongolica were distributed differently. The bacterial genera with CK were positively correlated with soil physicochemical properties, while a negative correlation was found for SS. In conclusion, the differences in nutrient and microbial community structure in the rhizosphere soil of Pinus sylvestris var. mongolica are the main causes of shoot blight disease.


2020 ◽  
Author(s):  
Han Li ◽  
Luyun Luo ◽  
Bin Tang ◽  
Huanle Guo ◽  
Zhongyang Cao ◽  
...  

Abstract Although rhizosphere microorganisms have been studied for a long time, rhizosphere microbial communities based on monoculture and intercropping soybean and maize have rarely been studied. To define the effect of crop monoculture and intercropping on soil physicochemical properties and rhizosphere bacterial communities, field experiments were conducted using maize and soybean cultivars at five different crop growth stages, including monoculture maize, monoculture soybean and maize-soybean intercropping. The rhizosphere bacterial communities were analyzed by using the 16S rRNA Illumina sequencing. The pH and soil organic matter (SOM) were the key factors affecting crop rhizosphere soil bacterial communities. The intercropping soybean-maize increased the available phosphorus (AP) content at five different crop growth stages. And the available potassium (AK) content in the intercropping soybean soil samples was higher than corresponding monoculture soil samples. The content of available cadmium (ACd) in monoculture soybean rhizosphere soil samples decreased and then increased, but the intercropping soybean soil samples indicated an opposite trend. Proteobacteria, Chloroflexi, Acidobacteria, Actinobacteria and Firmicutes were the dominant phyla in the soybean and maize rhizosphere soil samples. Crops of the same plant species showed little difference in the bacterial community diversity under the two planting modes. The results indicated the intercropping planting pattern altered the absorption of ACd in the maize and soybean soil since the S2 stage and showed a different change in different crop growth stages. And the maize-soybean intercropping system also changed the bacterial community and soil physicochemical properties.


2021 ◽  
Author(s):  
Zijun Zhou ◽  
Zengqiang Li ◽  
Kun Chen ◽  
Zhaoming Chen ◽  
Xiangzhong Zeng ◽  
...  

Abstract. Conservation tillage has attracted increasing attention over recent decades, mainly due to its benefits in improving soil organic matter content and reducing soil erosion. Under intensive conventional tillage systems, some studies have focused on the responses of soil properties in the topsoil to straw retention. However, long-term straw mulching effects on soil physicochemical properties and bacterial communities among different soil depths under a no-till system are still obscure. One twelve-year experiment was conducted that included straw removal (CK) and straw mulching (SM) treatments. Soil samples were collected at 0–5, 5–10, 10–20, and 20–30 cm soil depths. Most soil physicochemical properties and the relative abundances of bacterial phyla were varied with soil depth. Compared with CK, SM increased soil total nitrogen and organic carbon, available phosphorus and potassium, dissolved organic carbon and nitrogen, and water content. SM increased soil bacterial abundance but reduced the Shannon diversity of the bacterial community at 0–5 cm depth. SM increased the relative abundances of Proteobacteria, Bacteroidetes, and Acidobacteria but reduced those of Actinobacteria, Chloroflexi, and Cyanobacteria. SM had different effects on the relative abundances of some C- and N-cycling genera, for instance, increasing Rhodanobacter, Rhizomicrobium, and Terracidiphilus, and reducing Anaeromyxobacter, Mycobacterium, and Syntrophobacter. A principal coordinate analysis indicated that SM largely affected soil bacterial communities at topsoil depth. Soil pH and different nitrogen and organic carbon fractions were the major drivers shaping soil bacterial community. Overall, straw mulch is highly recommended for use under a no-till system because of its benefits to soil fertility and bacterial abundance. However, inorganic nitrogen fertilizer levels may be reduced under straw mulching to maintain or increase soil bacterial Shannon diversity in future studies.


2019 ◽  
Vol 11 (5) ◽  
pp. 1395 ◽  
Author(s):  
Junda Zhang ◽  
Suyan Li ◽  
Xiangyang Sun ◽  
Jing Tong ◽  
Zhen Fu ◽  
...  

Soil bacterial communities play a key role in nutrient cycling and ecosystem functioning. This study aims to reveal how green space type impacts soil quality and the bacterial community, which finally contributes to suggesting strategies for managing sustainable environments in urban areas. For this purpose, urban green space soils in this study are divided into four different types; park green space (PARK), street green space (STREET), attached green space (ATTACH) and residential green space (RESID). Results showed that significant differences were observed for soil physicochemical properties. Soil organic matter, total nitrogen, soil moisture content and available nitrogen in the ATTACH and PARK soils were significantly higher than in the STREET and RESID soils. Across the four green space types, the structure of bacterial communities was dominated by Proteobacteria, Actinobacteria and Chloroflexi at the phylum level. The diversity and richness of bacteria were significantly higher in the PARK and ATTACH soils than in the RESID and STREET soils. Results of principal component analysis (PCoA) showed that soil bacterial communities could be clustered into four different groups according to different green space types. In addition, analysis of similarities (ANOSIM) also implied that soil samples differed significantly from others. Redundancy analysis (RDA) and Spearman correlation analysis both showed that the contents of soil organic matter, total nitrogen, soil moisture and pH had great influence on the structures of bacterial communities. In summary, these results suggest that soil physicochemical properties and bacterial communities can be strongly affected by green space types, and thus, objective assessment of a particular measure can be provided to land managers and policy makers for informed decision-making in urban development and sustainability.


2009 ◽  
Vol 75 (15) ◽  
pp. 5111-5120 ◽  
Author(s):  
Christian L. Lauber ◽  
Micah Hamady ◽  
Rob Knight ◽  
Noah Fierer

ABSTRACT Soils harbor enormously diverse bacterial populations, and soil bacterial communities can vary greatly in composition across space. However, our understanding of the specific changes in soil bacterial community structure that occur across larger spatial scales is limited because most previous work has focused on either surveying a relatively small number of soils in detail or analyzing a larger number of soils with techniques that provide little detail about the phylogenetic structure of the bacterial communities. Here we used a bar-coded pyrosequencing technique to characterize bacterial communities in 88 soils from across North and South America, obtaining an average of 1,501 sequences per soil. We found that overall bacterial community composition, as measured by pairwise UniFrac distances, was significantly correlated with differences in soil pH (r = 0.79), largely driven by changes in the relative abundances of Acidobacteria, Actinobacteria, and Bacteroidetes across the range of soil pHs. In addition, soil pH explains a significant portion of the variability associated with observed changes in the phylogenetic structure within each dominant lineage. The overall phylogenetic diversity of the bacterial communities was also correlated with soil pH (R2 = 0.50), with peak diversity in soils with near-neutral pHs. Together, these results suggest that the structure of soil bacterial communities is predictable, to some degree, across larger spatial scales, and the effect of soil pH on bacterial community composition is evident at even relatively coarse levels of taxonomic resolution.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5508 ◽  
Author(s):  
Yan Li ◽  
Yan Kong ◽  
Dexiong Teng ◽  
Xueni Zhang ◽  
Xuemin He ◽  
...  

BackgroundRecently, researches have begun to investigate the microbial communities associated with halophytes. Both rhizobacterial community composition and the environmental drivers of community assembly have been addressed. However, few studies have explored the structure of rhizobacterial communities associated with halophytic plants that are co-occurring in arid, salinized areas.MethodsFive halophytes were selected for study: these co-occurred in saline soils in the Ebinur Lake Nature Reserve, located at the western margin of the Gurbantunggut Desert of Northwestern China. Halophyte-associated bacterial communities were sampled, and the bacterial 16S rDNA V3–V4 region amplified and sequenced using the Illumina Miseq platform. The bacterial community diversity and structure were compared between the rhizosphere and bulk soils, as well as among the rhizosphere samples. The effects of plant species identity and soil properties on the bacterial communities were also analyzed.ResultsSignificant differences were observed between the rhizosphere and bulk soil bacterial communities. Diversity was higher in the rhizosphere than in the bulk soils. Abundant taxonomic groups (from phylum to genus) in the rhizosphere were much more diverse than in bulk soils. Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Planctomycetes were the most abundant phyla in the rhizosphere, while Proteobacteria and Firmicutes were common in bulk soils. Overall, the bacterial community composition were not significantly differentiated between the bulk soils of the five plants, but community diversity and structure differed significantly in the rhizosphere. The diversity ofHalostachys caspica,Halocnemum strobilaceumandKalidium foliatumassociated bacterial communities was lower than that ofLimonium gmeliniiandLycium ruthenicumcommunities. Furthermore, the composition of the bacterial communities ofHalostachys caspicaandHalocnemum strobilaceumwas very different from those ofLimonium gmeliniiandLycium ruthenicum. The diversity and community structure were influenced by soil EC, pH and nutrient content (TOC, SOM, TON and AP); of these, the effects of EC on bacterial community composition were less important than those of soil nutrients.DiscussionHalophytic plant species played an important role in shaping associated rhizosphere bacterial communities. When salinity levels were constant, soil nutrients emerged as key factors structuring bacterial communities, while EC played only a minor role. Pairwise differences among the rhizobacterial communities associated with different plant species were not significant, despite some evidence of differentiation. Further studies involving more halophyte species, and individuals per species, are necessary to elucidate plant species identity effects on the rhizosphere for co-occurring halophytes.


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