scholarly journals Intercropping With Aromatic Plants Increased the Soil Organic Matter Content and Changed the Microbial Community in a Pear Orchard

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan Zhang ◽  
Mingzheng Han ◽  
Mengni Song ◽  
Ji Tian ◽  
Beizhou Song ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Community ◽  
Soil Organic Matter ◽  
Functional Groups ◽  
Root Exudates ◽  
Community Diversity ◽  
Rrna Gene ◽  
Aromatic Plants ◽  
Pear Orchard ◽  
Pear Trees

Intercropping influences the soil microbiota via litter and root exudate inputs, but the mechanisms by which root exudates mediate the soil microbial community and soil organic matter (SOM) are still unclear. In this study, we selected three aromatic plants (Ocimum basilicum, Tr1; Satureja hortensis, Tr2; Ageratum houstonianum, Tr3) as intercrops that separately grew between rows of pear trees, and no plants were grown as the control in a pear orchard during the spring–summer season for 3 years. The soil from each plot was collected using a stainless-steel corer by five-point sampling between rows of pear trees. The bacterial and fungal communities of the different aromatic intercrops were analyzed by 16S and ITS rRNA gene amplicon sequencing; their functional profiles were predicted by PICRUSt and FUNGuild analyses. The root exudates of the aromatic plants were analyzed by a liquid chromatography-tandem mass spectrometry (LC-MS) system. Compared with the control treatment, all intercropping treatments with aromatic plants significantly increased SOM and soil water content and decreased pH values. The contents of total nitrogen and alkali-hydrolyzable nitrogen in Tr1 and Tr2 were higher than those in Tr3. In Tr3 soil, the relative content of saccharides increased little, whereas the changes in amine (increases) and alcohols (decreases) were rapid. Ageratum houstonianum intercropping decreased the microbial community diversity and significantly influenced the relative abundances of the dominant microbiota (Actinobacteria, Verrucomicrobia, Gemmatimonadetes, Cyanobacteria, Ascomycota, and Basidiomycota) at the phylum, class, and order levels, which increased the assemblage of functional groups (nitrite ammonification, nitrate ammonification, and ureolysis groups). Our study suggested that the main root exudates from aromatic plants shaped the microbial diversity, structure, and functional groups related to the N cycle during SOM mineralization and that intercropping with aromatic plants (especially basil and summer savory) increased N release in the orchard soil.

scholarly journals Respiration of 13C-Labeled Substrates Added to Soil in the Field and Subsequent 16S rRNA Gene Analysis of 13C-Labeled Soil DNA

2003 ◽  
Vol 69 (3) ◽  
pp. 1614-1622 ◽  
Author(s):  
P. Padmanabhan ◽  
S. Padmanabhan ◽  
C. DeRito ◽  
A. Gray ◽  
D. Gannon ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
16S Rrna ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Gas Chromatography Mass Spectrometry ◽  
Rrna Gene ◽  
Labeled Compounds ◽  
Field Soil ◽  
Soil Dna

ABSTRACT Our goal was to develop a field soil biodegradation assay using 13C-labeled compounds and identify the active microorganisms by analyzing 16S rRNA genes in soil-derived 13C-labeled DNA. Our biodegradation approach sought to minimize microbiological artifacts caused by physical and/or nutritional disturbance of soil associated with sampling and laboratory incubation. The new field-based assay involved the release of 13C-labeled compounds (glucose, phenol, caffeine, and naphthalene) to soil plots, installation of open-bottom glass chambers that covered the soil, and analysis of samples of headspace gases for 13CO2 respiration by gas chromatography/mass spectrometry (GC/MS). We verified that the GC/MS procedure was capable of assessing respiration of the four substrates added (50 ppm) to 5 g of soil in sealed laboratory incubations. Next, we determined background levels of 13CO2 emitted from naturally occurring soil organic matter to chambers inserted into our field soil test plots. We found that the conservative tracer, SF6, that was injected into the headspace rapidly diffused out of the soil chamber and thus would be of little value for computing the efficiency of retaining respired 13CO2. Field respiration assays using all four compounds were completed. Background respiration from soil organic matter interfered with the documentation of in situ respiration of the slowly metabolized (caffeine) and sparingly soluble (naphthalene) compounds. Nonetheless, transient peaks of 13CO2 released in excess of background were found in glucose- and phenol-treated soil within 8 h. Cesium-chloride separation of 13C-labeled soil DNA was followed by PCR amplification and sequencing of 16S rRNA genes from microbial populations involved with 13C-substrate metabolism. A total of 29 full sequences revealed that active populations included relatives of Arthrobacter, Pseudomonas, Acinetobacter, Massilia, Flavobacterium, and Pedobacter spp. for glucose; Pseudomonas, Pantoea, Acinetobacter, Enterobacter, Stenotrophomonas, and Alcaligenes spp. for phenol; Pseudomonas, Acinetobacter, and Variovorax spp. for naphthalene; and Acinetobacter, Enterobacter, Stenotrophomonas, and Pantoea spp. for caffeine.

Interactions between typical functional groups of soil organic matter and mica (001) surface: A DFT study

2022 ◽  
Vol 216 ◽  
pp. 106374
Author(s):  
Hongping Zhang ◽  
Meng Chen ◽  
Chenghua Sun ◽  
Youhong Tang ◽  
Yuxiang Ni ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Functional Groups ◽  
Dft Study

Impact of sea level change on coastal soil organic matter, priming effects and prokaryotic community assembly

2019 ◽  
Vol 95 (10) ◽  
Author(s):  
Thomas Dinter ◽  
Simone Geihser ◽  
Matthias Gube ◽  
Rolf Daniel ◽  
Yakov Kuzyakov
Keyword(s):  
Organic Matter ◽  
Salt Marsh ◽  
Soil Organic Matter ◽  
Salt Marshes ◽  
Extracellular Enzymes ◽  
Rrna Gene ◽  
Co2 Efflux ◽  
Prokaryotic Community ◽  
Priming Effects ◽  
Niche Adaptation

ABSTRACT Salt marshes are coastal areas storing high amounts of soil organic matter (SOM) while simultaneously being prone to tidal changes. Here, SOM-decomposition and accompanied priming effects (PE), which describe interactions between labile and old SOM, were studied under controlled flooding conditions. Soil samples from two Wadden Sea salt marsh zones, pioneer (Pio), flooded two times/day, and lower salt marsh (Low), flooded ∼eight times/month, were measured for 56 days concerning CO2-efflux and prokaryotic community shifts during three different inundation-treatments: total-drained (Drained), all-time-flooded (Waterlogged) or temporal-flooding (Tidal). Priming was induced by 14C-glucose addition. CO2-efflux from soil followed Low>Pio and Tidal>Drained>Waterlogged, likely due to O2-depletion and moisture maintenance, two key factors governed by tidal inundation with regard to SOM mineralisation. PEs in both zones were positive (Drained) or absent (Waterlogged, Tidal), presumably as a result of prokaryotes switching from production of extracellular enzymes to direct incorporation of labile C. A doubled amount of prokaryotic biomass in Low compared to Pio probably induced higher chances of cometabolic effects and higher PE. 16S-rRNA-gene-amplicon-based analysis revealed differences in bacterial and archaeal community composition between both zones, revealing temporal niche adaptation with flooding treatment. Strongest alterations were found in Drained, likely due to inundation-mediated changes in C-binding capacities.

scholarly journals Temporal Changes in Archaeal Diversity and Chemistry in a Mid-Ocean Ridge Subseafloor Habitat

2002 ◽  
Vol 68 (4) ◽  
pp. 1585-1594 ◽  
Author(s):  
Julie A. Huber ◽  
David A. Butterfield ◽  
John A. Baross
Keyword(s):  
Microbial Community ◽  
Hydrothermal Systems ◽  
Community Diversity ◽  
Most Probable Number ◽  
Rrna Gene ◽  
Archaeal Diversity ◽  
Free Living ◽  
Probable Number ◽  
Diffuse Flow ◽  
Group I

ABSTRACT The temporal variation in archaeal diversity in vent fluids from a midocean ridge subseafloor habitat was examined using PCR-amplified 16S rRNA gene sequence analysis and most-probable-number (MPN) cultivation techniques targeting hyperthermophiles. To determine how variations in temperature and chemical characteristics of subseafloor fluids affect the microbial communities, we performed molecular phylogenetic and chemical analyses on diffuse-flow vent fluids from one site shortly after a volcanic eruption in 1998 and again in 1999 and 2000. The archaeal population was divided into particle-attached (>3-μm-diameter cells) and free-living fractions to test the hypothesis that subseafloor microorganisms associated with active hydrothermal systems are adapted for a lifestyle that involves attachment to solid surfaces and formation of biofilms. To delineate between entrained seawater archaea and the indigenous subseafloor microbial community, a background seawater sample was also examined and found to consist only of Group I Crenarchaeota and Group II Euryarchaeota, both of which were also present in vent fluids. The indigenous subseafloor archaeal community consisted of clones related to both mesophilic and hyperthermophilic Methanococcales, as well as many uncultured Euryarchaeota, some of which have been identified in other vent environments. The particle-attached fraction consistently showed greater diversity than the free-living fraction. The fluid and MPN counts indicate that while culturable hyperthermophiles represent less than 1% of the total microbial community, the subseafloor at new eruption sites does support a hyperthermophilic microbial community. The temperature and chemical indicators of the degree of subseafloor mixing appear to be the most important environmental parameters affecting community diversity, and it is apparent that decreasing fluid temperatures correlated with increased entrainment of seawater, decreased concentrations of hydrothermal chemical species, and increased incidence of seawater archaeal sequences.

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