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1.
Sci Total Environ ; 775: 145672, 2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33618307

RESUMO

A few researchers have reported enhancing soil physicochemical properties and reducing greenhouse gas emission using biochar-compost mixture as an alternative method to address soil fertility, soil degradation and climate change. However, information about its effects on soil microbiome has rarely been studied. This investigation was on the impact of a combined biochar-compost application on soil physicochemical variables, fungal community composition, function and network patterns in maize at seedling stage (SS), reproductive stage (RS), and maturity stage (MS). The experimental design consists of five treatments: control (CNT), compost (CMP), composted biochar (CMB), compost fortified with biochar (CFWB), biochar (BCH). The results showed that CFWB, CMB, and CMP increased fungal diversity indices (Shannon, Sobs, and Chao) at the RS and MS stages respectively, compared to BCH and CNT. Distance-based redundancy analysis (db-RDA) at genus level indicated that the pH, available nitrogen, and soil organic matter at SS; available phosphorus at RS; Mg, Mn, Fe, and Zn at MS significantly and positively affected the fungi community. Based on the Linear discriminant analysis (LDA) and effect size (LEfSe) analysis, the results revealed that only Cystofilobasidiaceae and Guehomyces were the MS biomarkers; and significantly enriched in CFWB. FUNGuild analysis indicated that organic amendments (CFWB, CMB, CMP, and BCH) suppressed the abundance of plant pathogenic fungi (Edenia and Waitea) compared to CNT. Network analysis showed that CFWB and CMB had a high niche overlap and cross-feeding in their networks compared to other treatments. However, CMP network had more positive links with Saprotroph, Pathotroph-Saprotroph-Symbiotroph, Pathotroph and Pathotroph-Symbiotroph compared with other treatments. This study showed that applying biochar, compost and a mixture of both, positively affected soil fungal communities plus co-occurrence network pattern in a single cropping season. Thus, their application as soil amendments may improve the soil fungi ecosystem, soil health and quality and mitigate climate change.

2.
Bioresour Technol ; 323: 124572, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33370679

RESUMO

This study investigated nitrification process during cattle manure-maize straw (CM) and biochar (CMB) composting in terms of multi-variable interaction (MVI) among environmental parameters, ammonia-oxidizing archaea (AOA) and bacteria (AOB) community structure, nitrogen-related enzymes as well as substrates using structural equation model (SEM). Results showed that adding biochar significantly reduced potential ammonia oxidation rates. SEM analysis revealed that AOB was affected by temperature and pH, which stimulated the release of urease, increased NH4+-N concentration and finally exerted influence on nitrification in CM. Temperature (0.755) and NO2--N (-0.994) were identified as the main factors mediating nitrification in CM and CMB, respectively. Moreover, MVI analysis indicated that nitrification and denitrification occurred simultaneously. Mutual verification of SEM and quantitative analyses (RNA level) confirmed that AOB predominated nitrification. The above results indicated that nitrification could be better explained by MVI using SEM during composting.


Assuntos
Compostagem , Esterco , Amônia , Animais , Archaea , Bovinos , Carvão Vegetal , Nitrificação , Oxirredução , Solo , Microbiologia do Solo , Zea mays
3.
Sci Total Environ ; : 142738, 2020 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-33097264

RESUMO

Increasing salinity and sodicity have been recognized as threats to soil fertility and crop yield worldwide. In recent years, salt-affected soils have received great attentions due to the shortage of arable land. This study therefore aims to characterize soil bacterial community, assembly process and co-occurrence network along natural saline-sodic gradients across Songnen Plain, Northeast China. As revealed by Miseq sequencing, 8482 bacterial OTUs were annotated at 97% identity across 120 soil samples. Our results indicated that soil salinity-sodicity not only significantly decreased bacterial richness and but also impacted bacterial community composition. The dominant bacterial phyla included Proteobacteria (28.89%), Actinobacteria (19.96%) and Gemmatimonadetes (16.71%). By applying threshold indicator species analysis (TITAN), OTUs from Gemmatimonadetes were found to be the taxa with the most prevalent and strongest preference for high salinity-sodicity. Null model analysis revealed that the majority (76.4%) of ßNTI values were below -2 or above 2, indicating deterministic process was dominant across all samples. Notably, deterministic process contributed to a greater extent in higher saline-sodic soils. The bacterial co-occurrence network was more complex in slightly saline-sodic soils than in moderately and extremely saline-sodic soils, reflected by more nodes, more hubs and stronger connections, which was mainly driven by soil pH. These results provide strong evidence that salinity-sodicity was a key determinant in shaping soil bacterial community, assembly process and co-occurrence network pattern.

4.
PeerJ ; 8: e8844, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32341890

RESUMO

Organic fertilizer application could have an impact on the nitrogen cycle mediated by microorganisms in arable soils. However, the dynamics of soil ammonia oxidizers and denitrifiers in response to compost addition are less understood. In this study, we examined the effect of four compost application rates (0, 11.25, 22.5 and 45 t/ha) on soil ammonia oxidizers and denitrifiers at soybean seedling, flowering and mature stage in a field experiment in Northeast China. As revealed by quantitative PCR, compost addition significantly enhanced the abundance of ammonia oxidizing bacteria (AOB) at seedling stage, while the abundance of ammonia oxidizing archaea was unaffected across the growing season. The abundance of genes involved in denitrification (nirS, nirK and nosZ) were generally increased along with compost rate at seedling and flowering stages, but not in mature stage. The non-metric multidimensional scaling analysis revealed that moderate and high level of compost addition consistently induced shift in AOB and nirS containing denitrifers community composition across the growing season. Among AOB lineages, Nitrosospira cluster 3a gradually decreased along with the compost rate across the growing season, while Nitrosomonas exhibited an opposite trend. Network analysis indicated that the complexity of AOB and nirS containing denitrifiers network gradually increased along with the compost rate. Our findings highlighted the positive effect of compost addition on the abundance of ammonia oxidizers and denitrifiers and emphasized that compost addition play crucial roles in shaping their community compositions and co-occurrence networks in black soil of Northeast China.

5.
Sci Total Environ ; 721: 137759, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32172117

RESUMO

A better understanding of the microbial group influencing nitrogen (N) dynamics and cycling in composting matrix is critical in achieving good management to alleviate N loss and improve final compost quality. This study investigated the bacterial composition, structure, co-occurrence network patterns and topological roles of N transformation in cattle manure-maize straw composting using high-throughput sequencing. The two treatments used in this experiment were cattle manure and maize straw mixture (CM) and CM with 10% biochar addition (CMB). In both treatments, the bacterial community composition varied during composting and the major phyla included Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes and Chloroflexi. The phyla Actinobacteria and Proteobacteria were more abundant in CMB treatment while Firmicutes was abundant in CM piles. The metabolic functional profiles of bacteria was predicted using the "phylogenetic investigation of communities by reconstruction of unobserved states" (PICRUSt) which revealed that except for cellular processes pathway, CMB had slight higher abundance in metabolism, genetic information processing and environmental information processing than the CM. Pearson correlation revealed more significant relationship between the important bacteria communities and N transformation in CMB piles compared with CM. Furthermore, network pattern analysis revealed that the bacterial networks in biochar amended piles are more complex and harbored more positive links than that of no biochar piles. Corresponding agreement of multivariate analyses (correlation heatmap, stepwise regression, Path and network analyses) revealed that Psychrobacter, Thermopolyspora and Thermobifida in CM while Corynebacterium_1, Thermomonospora and Streptomyces in CMB were key bacterial genera affecting NH4+-N, NO3--N and total nitrogen (TN) transformation respectively during composting process. These results provide insight into nitrogen transformation and co-occurrence patterns mediating microbes and bacterial metabolism which could be useful in enhancing compost quality and mitigating N loss during composting.


Assuntos
Compostagem , Microbiota , Animais , Bovinos , Carvão Vegetal , Esterco , Nitrogênio , Filogenia , Solo , Zea mays
6.
Waste Manag ; 105: 190-197, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32078983

RESUMO

Analyzing diazotrophic community may help to understand nitrogen transformation in composting and improves the final compost quality. In this study, diazotrophic community dynamics were investigated in terms of nifH gene during dairy manure and corn straw composting with biochar addition using high-throughput sequencing. Biochar decreased the diversity of diazotrophic community and altered diazotroph community structure during composting. At phylum level, Proteobacteria, Actinobacteria and Firmicutes were dominant diazotrophic communities throughout composting process. Biochar addition registered higher correlation coefficient (R) between physicochemical factors (temperature, ammonium (NH4+-N) and nitrate (NO3--N)) and diazotroph community composition. Rhodopseudomonas and Pseudoxanthomonas was the key diazotrophic communities influencing NH4+-N transformation in control (CK) and biochar compost (BC), respectively, while for NO3--N transformation Clostridium and Bradyrhizobium in CK, Azospira and Methylocystis in BC served as predominant factors. These results indicated that addition of biochar altered the key diazotroph communities influencing nitrogen transformation. Furthermore, some diazotrophs (e.g. Rhodopseudomonas, Bradyrhizobium and Azospira) affecting NH4+-N and NO3--N transformation were also observed to be mediating total nitrogen (TN). Interestingly, interactions between diazotrophic communities were observed and these interactions could also influence nitrogen transformation.


Assuntos
Compostagem , Carvão Vegetal , Esterco , Nitrogênio , Solo
7.
Ecotoxicol Environ Saf ; 191: 110161, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31954219

RESUMO

Denitrification and nitrification processes are the two prominent pathways of nitrogen (N) transformation in composting matrix. This study explored the dynamics of denitrifying and nitrifying bacteria at different composting stages of cow manure and corn straw using functional gene sequencing at DNA and cDNA levels. Corresponding agreement among OTUs, NMDS, mental test and network analyses revealed that functional bacteria community compositions and responses to physicochemical factors were different at DNA and cDNA levels. Specifically, some OTUs were detected at the DNA level but were not observed at cDNA level, differences were also found in the distribution patterns of nitrifying and denitrifying bacteria communities at both levels. Furthermore, co-occurrence network analysis indicated that Pseudomonas, Paracoccus and Nitrosomonas were identified as the keystone OTUs at the DNA level, while Paracoccus, Agrobacterium and Nitrosospira were keystone OTUs at the cDNA level. Mantel test revealed that TN, C/N and moisture content significantly influenced both the denitrifying bacteria and ammonia-oxidizing bacteria (AOB) communities at the DNA level. NO3--N, NH4+-N, TN, C/N, and moisture content only registered significant correlation with the nosZ-type denitrifiers and ammonia-oxidizing bacteria (AOB) communities at the cDNA level. Structural equation model (SEM) showed that TN, NH4+-N, and pH were direct and significantly influenced the gene abundance of denitrifying bacteria. Howbeit, TN, NH4+-N, and NO3--N had significant direct effects on amoA gene abundance.


Assuntos
Betaproteobacteria/isolamento & purificação , Compostagem , DNA Bacteriano/genética , DNA Complementar/genética , Esterco/microbiologia , Amônia/metabolismo , Animais , Betaproteobacteria/genética , Betaproteobacteria/metabolismo , Bovinos , China , Desnitrificação , Feminino , Microbiota/genética , Nitrificação , Nitrogênio/metabolismo , Oxirredução
8.
Biotechnol Appl Biochem ; 67(5): 799-811, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746033

RESUMO

In this study, nutrient loss, the direct and indirect relationship between period, compost types, temperature, total nitrogen (TN), nitrate nitrogen (NO3 - -N), ammonium nitrogen (NH4 + -N), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) were investigated during composting of cattle manure-maize straw mixture. This study findings revealed that biochar addition lowered NH4 + -N but did not increase NO3 - -N concentrations unlike no biochar piles during composting. The first-order kinetic models showed that biochar accelerated organic matter (OM) degradation and improved nitrogen mineralization, consequently reducing TN losses by 13.6% and OM losses by 12.66%. Transformation ratio of MBC/MBN, coupled with other chemical components of the entire microbial community, suggested a shift in the microbial succession and diversity during composting from the dominant bacteria and actinomycetes to fungi. The structural equation model and path coefficient revealed temperature to be the main factor mediating the evolution of MBC and MBN in composting. The physicochemical variables, phytotoxicity, and final product quality revealed that biochar incorporation to the composting feedstock is an ideal material for mitigating problems of TN and OM losses in composting and ultimately enhancing the fertility potential of the final compost product.

9.
Bioresour Technol ; 291: 121815, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31344636

RESUMO

In this study, mechanism of nitrogen transformation was investigated in terms of genetic associations (nitrogen-related gene groups) in co-composting of cattle manure and rice straw. Mutual validation among KEGG, Pearson correlation, stepwise regression, and Path analyses indicated that the functional genes synergistically affected on nitrogen transformation in composting process. NxrA/qnorB (0.9419 ±â€¯0.0334) and (amoA + anammox)/Bacteria (0.7187 ±â€¯0.0334) were the key functional gene groups mediating NH4+-N transformation. AmoA/(narG + napA) (-0.8400 ±â€¯0.0129), amoA/bacteria (0.8692 ±â€¯0.0273), and (nirK + nirS)/nosZ (1.1652 ±â€¯0.0089) determined NO3--N, NO2--N and N2O transformation, respectively. AmoA/(napA + narG) mediated both NO3--N and NO2--N transformation. AmoA/anammox (-0.7172 ±â€¯0.0591) and (nirK + nirS)/nosZ (-0.6626 ±â€¯0.0825) served as predominant factors for total nitrogen removal. These results provided a molecular-level insight that nitrification, anaerobic ammonia oxidation and denitrification (SNAD) might simultaneously contribute to nitrogen transformation during composting, rather than sequentially.


Assuntos
Compostagem , Oryza , Animais , Bovinos , Desnitrificação , Esterco , Nitrificação , Nitrogênio
10.
Waste Manag ; 92: 59-67, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31160027

RESUMO

Insight to nitrogen transformation and cycling during composting is vital in developing management strategies that improve nitrogen content and quality of the end product. In this study, a positive ventilation device was constructed and used to elucidate nitrogen transformation and microbial community structures during the composting of cow manure and rice straw. Bacterial community successions were analyzed during the composting process by examining the change in their structural dynamics using high-throughput sequencing technique. The results revealed that dominant phyla, included Acidobacter, Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, and Actinobacteria. Furthermore, a positive strong correlation was observed between the key bacterial communities and nitrogen transformation. Analyses of functional genera, Spearman correlation and Path showed that Thermomonospora_curvata_DSM_43183 followed by Luteimonas and Simiduia, Brevundimonas and Tamlana, Pseudomonas followed by Brevundimonas and Flavobacterium were the key bacterial communities affecting NH4+-N, NO3--N, and NO2--N transformation, respectively. Thauera followed by Pseudomonas_putida_NBRC_14164 played a dominant role in N2O transformation.


Assuntos
Compostagem , Microbiota , Animais , Bovinos , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Esterco , Nitrogênio , Solo
11.
Front Microbiol ; 10: 529, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30936861

RESUMO

In composting system, the composition of microbial communities is determined by the constant change in the physicochemical parameters. This study explored the dynamics of bacterial and fungal communities during cow manure and corn straw composting using high throughput sequencing technology. The relationships between physicochemical parameters and microbial community composition and abundance were also evaluated. The sequencing results revealed the major phyla included Proteobacteria, Bacteroidetes, Firmicutes, Chloroflexi and Actinobacteria, Ascomycota, and Basidiomycota. Linear discriminant analysis effect size (LEfSe) illustrated that Actinomycetales and Sordariomycetes were the indicators of bacteria and fungi in the maturation phase, respectively. Mantel test showed that NO3 --N, NH4 +-N, TN, C/N, temperature and moisture content significantly influenced bacterial community composition while only TN and moisture content had a significant effect on fungal community structure. Structural equation model (SEM) indicated that TN, NH4 +-N, NO3 --N and pH had a significant effect on fungal abundance while TN and temperature significantly affected bacterial abundance. Our finding increases the understanding of microbial community succession in cow manure and corn straw composting under natural conditions.

12.
Can J Microbiol ; 65(6): 436-449, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30861347

RESUMO

This study applied high-throughput sequencing technology and PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved state) to examine the microbial population dynamics during the composting of dairy manure and rice straw in a static (without turning) composting system. The results showed that the composition of the bacterial community varied significantly during the composting process. The dominant phyla included Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi. Biodiversity indices showed that bacterial community diversity had the peak value during the mesophilic phase. Redundancy analysis indicated that nitrogen was the most important factor in the distribution of genera during the composting process. Finally, the Pearson correlation results suggested that Thermomonospora and Thermopolyspora could be the biomarkers of the composting maturation phase. The metabolic characteristics of the bacterial communities were predicted by PICRUSt. The result showed that metabolism of amino acids, lipids, and most of the carbohydrates increased during the whole composting treatment. However, methane metabolism, carbon fixation pathways in prokaryotes, and nucleotide metabolism decreased after the thermophilic phase. The present study provides a better understanding for bacterial community composition and function succession in dairy manure composting.


Assuntos
Bactérias/isolamento & purificação , Compostagem , Esterco/microbiologia , Microbiologia do Solo , Animais , Bactérias/classificação , Biodiversidade , Bovinos , Nitrogênio , Oryza/microbiologia , Filogenia
13.
Front Microbiol ; 9: 169, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29467752

RESUMO

Arbuscular mycorrhizal (AM) fungi form symbiotic associations with most crop plant species in agricultural ecosystems, and are conspicuously influenced by various agricultural practices. To understand the impact of compost addition on AM fungi, we examined effect of four compost rates (0, 11.25, 22.5, and 45 Mg/ha) on the abundance and community composition of AM fungi in seedling, flowering, and mature stage of soybean in a 1-year compost addition experiment system in Northeast China. Soybean [Glycine max (L.) Merrill] was used as test plant. Moderate (22.5 Mg/ha) and high (45 Mg/ha) levels of compost addition significantly increased AM root colonization and extraradical hyphal (ERH) density compared with control, whereas low (11.5 Mg/ha) level of compost addition did not cause significant increase in AM root colonization and ERH density. AM fungal spore density was significantly enhanced by all the compost rates compared with control. The temporal variations analysis revealed that, AM root colonization in seedling stage was significantly lower than in flowering and mature stage. Although AM fungal operational taxonomic unit richness and community composition was unaffected by compost addition, some abundant AM fungal species showed significantly different response to compost addition. In mature stage, Rhizophagus fasciculatum showed increasing trend along with compost addition gradient, whereas the opposite was observed with Paraglomus sp. In addition, AM fungal community composition exhibited significant temporal variation during growing season. Further analysis indicated that the temporal variation in AM fungal community only occurred in control treatment, but not in low, moderate, and high level of compost addition treatments. Our findings highlighted the significant effects of compost addition on AM growth and sporulation, and emphasized that growth stage is a stronger determinant than 1-year compost addition in shaping AM fungal community in black soil of Northeast China.

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