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Wang X.,Yangzhou University | Wang X.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Liang G.,Jiangsu University
BioMed Research International | Year: 2014

We aimed to isolate and identify endophytic bacteria that might have efficacy against peanut bacterial wilt (BW) caused by Ralstonia solanacearum. Thirty-seven endophytic strains were isolated from healthy peanut plants in R. solanacearum-infested fields and eight showed antagonistic effects against R. solanacearum. Strain BZ6-1 with the highest antimicrobial activity was identified as Bacillus amyloliquefaciens based on morphology, biochemistry, and 16S rRNA analysis. Culture conditions of BZ6-1 were optimized using orthogonal test method and inhibitory zone diameter in dual culture plate assay reached 34.2 mm. Furthermore, main antimicrobial substances of surfactin and fengycin A homologues produced by BZ6-1 were analyzed by high performance liquid chromatography electrospray ionization tandem mass spectrometry. Finally, pot experiments were adopted to test the control efficiency of BZ6-1 against peanut BW. Disease incidence decreased significantly from 84.5% in the control to 12.1% with addition of 15 mL (108 cfu mL-1) culture broth for each seedling, suggesting the feasibility of strain BZ6-1 in the biological control of peanut plants BW. © 2014 Xiaobing Wang and Guobin Liang.


Song X.,Nanjing Agricultural University | Song X.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Liu M.,Nanjing Agricultural University | Liu M.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | And 13 more authors.
Waste Management | Year: 2014

A pilot-scale trial of four months was conducted to investigate the responses of heavy metal and nutrient to composting animal manure spiked with mushroom residues with and without earthworms. Results showed that earthworm activities accelerated organic matter mineralization (e.g. reduction in C/N ratio, increase in total concentrations of N, P, K) and humification (e.g. increase in humic acid concentration, humification ratio and humification index). Despite composting increased total heavy metal (i.e. As, Pb, Cu, Zn) concentrations irrespective of earthworm, the availability of heavy metals extracted by DTPA significantly (P< 0.05) decreased particularly in treatments with earthworms introduced. The shift from available to unavailable fractions of heavy metals was either due to earthworm bioaccumulation, as indicated by total heavy metal concentrations being higher in earthworm tissues, or due to the formation of stable metal-humus complexes as indicated by the promotion of humification. Our results suggest that vermicomposting process could magnify the nutrient quality but relieve the heavy metals risk of agricultural organic wastes. © 2014 Elsevier Ltd.


Wang Z.,Nanjing Agricultural University | Zheng G.,Nanjing Agricultural University | Zheng G.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Zhou L.,Nanjing Agricultural University | Zhou L.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization
Bioresource Technology | Year: 2015

Mechanisms responsible for the sludge dewaterability enhanced by filamentous fungi during fungal treatment of sludge were investigated in the present study. The filamentous fungus Mucor sp. GY-1, isolated from waste activated sludge, enhanced sludge dewaterability by 82.1% to achieve the lowest value of normalized sludge specific resistance to filtration (SRF), 8.18×1010m·L/kg·g-TSS. During the fungal treatment of sludge, 57.8% of slime extracellular polymeric substances (EPS) and 51.1% of polysaccharide in slime EPS were degraded, respectively, by Mucor sp. GY-1, contributing to the improvement of sludge dewaterability. Slime EPS is much more available for Mucor sp. GY-1 than either LB-EPS or TB-EPS that bound with microbial cells. In addition, filamentous fungus Mucor sp. GY-1 entrapped small sludge particles and inhibited the destruction of sludge flocs larger than 100μm, thus enhancing sludge dewaterability, during fungal treatment of sludge using Mucor sp. GY-1. © 2015 Elsevier Ltd.


Zhao J.,Key Laboratory of Plant Nutrition and Fertilization in Low Middle Reaches of the Yangtze River | Zhao J.,Nanjing Agricultural University | Zhang R.,Key Laboratory of Plant Nutrition and Fertilization in Low Middle Reaches of the Yangtze River | Zhang R.,Nanjing Agricultural University | And 13 more authors.
Microbial Ecology | Year: 2014

Microbes are key components of the soil environment, playing an important role in maintaining soil health, sustainability, and productivity. The composition and structure of soil bacterial communities were examined in winter wheat-rice (WR) and winter wheat-maize (WM) cropping systems derived from five locations in the Low-Middle Yangtze River plain and the Huang-Huai-Hai plain by pyrosequencing of the 16S ribosomal RNA gene amplicons. A total of 102,367 high quality sequences were used for multivariate statistical analysis and to test for correlation between community structure and environmental variables such as crop rotations, soil properties, and locations. The most abundant phyla across all soil samples were Proteobacteria, Acidobacteria, and Bacteroidetes. Similar patterns of bacterial diversity and community structure were observed within the same cropping systems, and a higher relative abundance of anaerobic bacteria was found in WR compared to WM cropping systems. Variance partitioning analysis revealed complex relationships between bacterial community and environmental variables. The effect of crop rotations was low but significant, and interactions among soil properties, locations, and crop rotations accounted for most of the explained variation in the structure of bacterial communities. Soil properties such as pH, available P, and available K showed higher correlations (positive or negative) with the majority of the abundant taxa. Bacterial diversity (the Shannon index) and richness (Chao1 and ACE) were higher under WR than WM cropping systems. © 2013 Springer Science+Business Media New York.


Zhang D.,Nanjing Agricultural University | Zhang D.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Pan G.,Nanjing Agricultural University | Pan G.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | And 17 more authors.
Chemosphere | Year: 2016

Maize production plays an important role in global food security, especially in arid and poor-soil regions. Its production is also increasing in China in terms of both planting area and yield. However, maize productivity in rainfed croplands is constrained by low soil fertility and moisture insufficiency. To increase the maize yield, local farmers use NPK fertilizer. However, the fertilization regime (CF) they practice is unbalanced with too much nitrogen in proportion to both phosphorus and potassium, which has led to low fertilizer use efficiency and excessive greenhouse gases emissions. A two-year field experiment was conducted to assess whether a high yielding but low greenhouse gases emission system could be developed by the combination of balanced fertilization (BF) and biochar amendment in a rainfed farmland located in the Northern region of China. Biochar was applied at rates of 0, 20, and 40t/ha. Results show that BF and biochar increased maize yield and partial nutrient productivity and decreased nitrous oxide (N2O) emission. Under BF the maize yield was 23.7% greater than under CF. N2O emissions under BF were less than half that under CF due to a reduced N fertilizer application rate. Biochar amendment decreased N2O by more than 31% under CF, while it had no effect on N2O emissions under BF. Thus BF was effective at maintaining a high maize yield and reducing greenhouse gases emissions. If combined with biochar amendment, BF would be a good way of sustaining low carbon agriculture in rainfed areas. © 2015 Elsevier Ltd.


Yu D.,Nanjing Agricultural University | Yu D.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Yan Q.,Nanjing Agricultural University | Liu M.,Nanjing Agricultural University | Liu M.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization
ZooKeys | Year: 2016

Two new troglobitic species of Tomoceridae are described from Guizhou and Guangxi provinces, China. Tomocerus tiani sp. n. resembles Tomocerus kinoshitai Yosii, 1954, Tomocerus caecus Yu & Deharveng, 2015 and Tomocerus similis Chen & Ma, 1997 but differs from them mainly in the body colour, the cephalic chaetotaxy and the number of manubrial pseudopores. Monodontocerus cinereus sp. n. is similar to Monodontocerus mulunensis Yu, Deharveng & Zhang, 2014 but is different from the latter in the body colour, the length of antennae, the number of ungual teeth and the chaetotaxy on Abd. III and Abd. IV. Special remarks are made on the mesothoracic bothriotricha in Tomocerinae. © Daoyuan Yu et al..


Liu T.,Nanjing Agricultural University | Liu T.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Liu T.,McGill University | Chen X.,Nanjing Agricultural University | And 7 more authors.
Agriculture, Ecosystems and Environment | Year: 2016

Organic fertilizer applications that boost soil fertility and crop production are expected to enhance soil biodiversity, making ecosystems more resilient to stress. Numerous studies have compared biodiversity in soil receiving organic fertilizer to soil under other fertilizer regimes (inorganic fertilizers, unfertilized), yet the data were not analyzed systematically across studies. We evaluated fertilizer effects on soil nematode communities with a meta-analysis of more than 229 data points from 54 studies around the world that were published between 1996 and 2015. Data were from cropland and considered five fertilizer regimes. These regimes include unfertilized soils and those receiving inorganic fertilizers (2 regimes), as well as organic fertilizers (2 regimes). Species richness and total nematode abundance increased with increasing carbon (C) inputs from fertilizers, whereas greater nitrogen (N) application rates from fertilizers significantly reduced the species richness, Shannon's diversity (H′), maturity index (MI) and omnivore-predator nematode abundance. This could indicate that high fertilizer N inputs simplifies the nematode community structure and functions. Species richness, omnivore-predator nematode abundance and structural index (SI) increased with the organically-fertilized regime and declined in inorganically-fertilized regimes, suggesting that organic fertilizers can buffer stresses and sustain soil food web functions. Furthermore, organic fertilizers differed in their impact on soil nematodes, as those with C-rich crop residues supported larger free-living nematode populations and greatly promoted H′, SI and enrichment index (EI), whereas N-rich animal manure was more effective in controlling plant-feeding nematodes. Our review suggests that the application of C-rich crop residues is the most effective practice to enhance soil biodiversity in intensively managed agroecosystems, highlighting the importance of regular applications of straw and other C-rich residues to preserve the ecological resilience of cropland. © 2016 Elsevier B.V.


Zhou J.,Nanjing Agricultural University | Zhou J.,Nanjing University of Technology | Zheng G.,Nanjing Agricultural University | Zheng G.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | And 3 more authors.
PLoS ONE | Year: 2014

Extracellular polymeric substances (EPS) play important roles in regulating the dewaterability of sludge. This study sought to elucidate the influence of EPS on the dewaterability of sludge during bioleaching process. Results showed that, in bioleaching system with the co-inoculation of Acidithiobacillus thiooxidans TS6 and Acidithiobacillus ferrooxidans LX5 (A. t+A. f system), the capillary suction time (CST) of sludge reduced from 255.9 s to 25.45 s within 48 h, which was obviously better than the controls. The correlation analysis between sludge CST and sludge EPS revealed that the sludge EPS significantly impacted the dewaterability of sludge. Sludge CST had correlation with protein content in slime and both protein and polysaccharide contents in TB-EPS and Slime+LB +TB layers, and the decrease of protein content in slime and decreases of both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers improved sludge dewaterability during sludge bioleaching process. Moreover, the low sludge pH (2.92) and the increasing distribution of Fe in the solid phase were another two factors responsible for the improvement of sludge dewaterability during bioleaching. This study suggested that during sludge bioleaching the growth of Acidithiobacillus species resulted in the decrease of sludge pH, the increasing distribution of Fe in the solid phase, and the decrease of EPS content (mainly including protein and/or polysaccharide) in the slime, TB-EPS, and Slime+LB+TB layers, all of which are helpful for sludge dewaterability enhancement. © 2014 Zhou et al.


Yu D.,Nanjing Agricultural University | Yu D.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Li Y.,Guangxi Normal University
Zootaxa | Year: 2016

Three new troglobitic species of Tomocerus are described from the southwestern karsts of China. All of them have well developed postantennal organs. Tomocerus dong sp. nov. is similar to Tomocerus postantennalis Yu, Zhang & Deharveng and Tomocerus deharvengi sp. nov., but is different from them mainly in the number of prelabral chaetae and the dorsal body chaetotaxy. T. deharvengi sp. nov. is very similar to T. postantennalis but differs from the latter in the cephalic chaetotaxy, the number of manubrial pseudopores and the number of dental spines. T. cthulhu sp. nov. is peculiar for the multi-furcated vesicles of ventral tube, and is different from the three aforementioned species mainly in the dorsal body chaetotaxy. The position of the new species and the relationships between them are discussed. Copyright © 2016 Magnolia Press.


Huo M.,Nanjing Agricultural University | Zheng G.,Nanjing Agricultural University | Zheng G.,Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization | Zhou L.,Nanjing Agricultural University
Bioresource Technology | Year: 2014

Contribution rates of factors controlling sludge dewaterability during bioleaching, such as sludge pH, microbial quantity, extracellular polymeric substances (EPS), etc., were investigated in this study. Results showed that the dewaterability of bioleached sludge was jointly enhanced by the growth of Acidithiobacillus sp., the increase of Fe3+ concentration, the decreases of sludge pH, heterotrophic microorganism quantity change, and the decreases of EPS and bound water contents. Ridge regression analysis further revealed that the contribution rates of microbial quantity change, bound water content and slime EPS content on sludge dewaterability enhancement were 32.50%, 24.24%, and 22.37%, respectively, all of which are dominant factors. Therefore, the enhancement of sludge dewaterability was mainly controlled by microbial quantity change and the decrease of bound water and slime EPS contents during bioleaching. © 2014 Elsevier Ltd.

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