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Profile Changes in the Soil Microbial Community When Desert Becomes Oasis.

Li CH, Tang LS, Jia ZJ, Li Y - PLoS ONE (2015)

Bottom Line: To assess the effects of cultivation, the following treatments were compared with the virgin desert: CK (no fertilizer), PK, NK, NP, NPK, NPKR, and NPKM (R: straw residue; M: manure fertilizer).The proportions of extremophilic and photosynthetic groups (e.g., Deinococcus-Thermus and Cyanobacteria) decreased, while the proportions of R-strategy (e.g., Gammaproteobacteria including Xanthomonadales), nitrifying (e.g., Nitrospirae), and anaerobic bacteria (e.g., Anaerolineae) increased throughout the oasis profile.Furthermore, difference in fertilization and crop growth altered the organic carbon contents in the soil, which resulted in differences of microbial communities within oasis.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China.

ABSTRACT
The conversion of virgin desert into oasis farmland creates two contrasting types of land-cover. During oasis formation with irrigation and fertilizer application, however, the changes in the soil microbial population, which play critical roles in the ecosystem, remain poorly understood. We applied high-throughput pyrosequencing to investigate bacterial and archaeal communities throughout the profile (0-3 m) in an experimental field, where irrigation and fertilization began in 1990 and cropped with winter wheat since then. To assess the effects of cultivation, the following treatments were compared with the virgin desert: CK (no fertilizer), PK, NK, NP, NPK, NPKR, and NPKM (R: straw residue; M: manure fertilizer). Irrigation had a greater impact on the overall microbial community than fertilizer application. The greatest impact occurred in topsoil (0-0.2 m), e.g., Cyanobacteria (25% total abundance) were most abundant in desert soil, while Actinobacteria (26%) were most abundant in oasis soil. The proportions of extremophilic and photosynthetic groups (e.g., Deinococcus-Thermus and Cyanobacteria) decreased, while the proportions of R-strategy (e.g., Gammaproteobacteria including Xanthomonadales), nitrifying (e.g., Nitrospirae), and anaerobic bacteria (e.g., Anaerolineae) increased throughout the oasis profile. Archaea occurred only in oasis soil. The impact of fertilizer application was mainly reflected in the non-dominant communities or finer taxonomic divisions. Oasis formation led to a dramatic shift in microbial community and enhanced soil enzyme activities. The rapidly increased soil moisture and decreased salt caused by irrigation were responsible for this shift. Furthermore, difference in fertilization and crop growth altered the organic carbon contents in the soil, which resulted in differences of microbial communities within oasis.

No MeSH data available.


Ordination plots of the results from canonical correspondence analysis (CCA) in topsoil (0–0.2 m) to explore the relationship between microbial populations and soil properties, such as soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), soil pH, electric conductivity (EC), and soil water content (SWC) for different fertilizer treatments (CK, PK, NK, NP, NPK, NPKR and NPKM) with (A) and without desert soil (B).Cyanobacteria = Cya, Deinococcus-Thermus = Dei, Actinobacteria = Act, Alphaproteobacteria = Alp, Betaproteobacteria = Bet, Gammaproteobacteria = Gam, Deltaproteobacteria = Del, Acidobacteria = Aci, Firmicutes = Fir, Chloroflexi = Chl, Gemmatimonadetes = Gem, Nitrospirae = Nit, Planctomycetes = Pla, Bacteroidetes = Bac, Crenarchaeota = Cre.
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pone.0139626.g004: Ordination plots of the results from canonical correspondence analysis (CCA) in topsoil (0–0.2 m) to explore the relationship between microbial populations and soil properties, such as soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), soil pH, electric conductivity (EC), and soil water content (SWC) for different fertilizer treatments (CK, PK, NK, NP, NPK, NPKR and NPKM) with (A) and without desert soil (B).Cyanobacteria = Cya, Deinococcus-Thermus = Dei, Actinobacteria = Act, Alphaproteobacteria = Alp, Betaproteobacteria = Bet, Gammaproteobacteria = Gam, Deltaproteobacteria = Del, Acidobacteria = Aci, Firmicutes = Fir, Chloroflexi = Chl, Gemmatimonadetes = Gem, Nitrospirae = Nit, Planctomycetes = Pla, Bacteroidetes = Bac, Crenarchaeota = Cre.

Mentions: Given that the strongest impact of oasis formation on the microbial community occurred in the topsoil and most community responses were similar throughout the soil profile, we present here only the CCA ordination for topsoil. The ordination plots demonstrate the community differentiations between the desert and oasis soils (Fig 4A), and between different fertilizer applications (Fig 4B). In Fig 4A, the desert soils are centered in areas with low soil moisture and high EC; while the seven treatments of the oasis soils had a relatively concentrated distribution in the opposite area. This indicates that the microbial community structure in the desert soil was completely different from that of the oasis soil, while all treatments in the oasis soil produced roughly similar community structures. However, in the plot without the desert soil (Fig 4B), fertilizer applications exerted significant effects on the microbial community. These treatments were dispersed in different areas of the ordination plot. The CK, PK, and NK treatments were centered along a gradient with relatively high EC, pH, and relatively low SOC and nutrient contents. The combined treatments with organic fertilizers (NPKR and NPKM) were centered on the area with high SOC and nutrient contents and low EC and pH. The NP and NPK treatments were distributed in another area.


Profile Changes in the Soil Microbial Community When Desert Becomes Oasis.

Li CH, Tang LS, Jia ZJ, Li Y - PLoS ONE (2015)

Ordination plots of the results from canonical correspondence analysis (CCA) in topsoil (0–0.2 m) to explore the relationship between microbial populations and soil properties, such as soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), soil pH, electric conductivity (EC), and soil water content (SWC) for different fertilizer treatments (CK, PK, NK, NP, NPK, NPKR and NPKM) with (A) and without desert soil (B).Cyanobacteria = Cya, Deinococcus-Thermus = Dei, Actinobacteria = Act, Alphaproteobacteria = Alp, Betaproteobacteria = Bet, Gammaproteobacteria = Gam, Deltaproteobacteria = Del, Acidobacteria = Aci, Firmicutes = Fir, Chloroflexi = Chl, Gemmatimonadetes = Gem, Nitrospirae = Nit, Planctomycetes = Pla, Bacteroidetes = Bac, Crenarchaeota = Cre.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591283&req=5

pone.0139626.g004: Ordination plots of the results from canonical correspondence analysis (CCA) in topsoil (0–0.2 m) to explore the relationship between microbial populations and soil properties, such as soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), soil pH, electric conductivity (EC), and soil water content (SWC) for different fertilizer treatments (CK, PK, NK, NP, NPK, NPKR and NPKM) with (A) and without desert soil (B).Cyanobacteria = Cya, Deinococcus-Thermus = Dei, Actinobacteria = Act, Alphaproteobacteria = Alp, Betaproteobacteria = Bet, Gammaproteobacteria = Gam, Deltaproteobacteria = Del, Acidobacteria = Aci, Firmicutes = Fir, Chloroflexi = Chl, Gemmatimonadetes = Gem, Nitrospirae = Nit, Planctomycetes = Pla, Bacteroidetes = Bac, Crenarchaeota = Cre.
Mentions: Given that the strongest impact of oasis formation on the microbial community occurred in the topsoil and most community responses were similar throughout the soil profile, we present here only the CCA ordination for topsoil. The ordination plots demonstrate the community differentiations between the desert and oasis soils (Fig 4A), and between different fertilizer applications (Fig 4B). In Fig 4A, the desert soils are centered in areas with low soil moisture and high EC; while the seven treatments of the oasis soils had a relatively concentrated distribution in the opposite area. This indicates that the microbial community structure in the desert soil was completely different from that of the oasis soil, while all treatments in the oasis soil produced roughly similar community structures. However, in the plot without the desert soil (Fig 4B), fertilizer applications exerted significant effects on the microbial community. These treatments were dispersed in different areas of the ordination plot. The CK, PK, and NK treatments were centered along a gradient with relatively high EC, pH, and relatively low SOC and nutrient contents. The combined treatments with organic fertilizers (NPKR and NPKM) were centered on the area with high SOC and nutrient contents and low EC and pH. The NP and NPK treatments were distributed in another area.

Bottom Line: To assess the effects of cultivation, the following treatments were compared with the virgin desert: CK (no fertilizer), PK, NK, NP, NPK, NPKR, and NPKM (R: straw residue; M: manure fertilizer).The proportions of extremophilic and photosynthetic groups (e.g., Deinococcus-Thermus and Cyanobacteria) decreased, while the proportions of R-strategy (e.g., Gammaproteobacteria including Xanthomonadales), nitrifying (e.g., Nitrospirae), and anaerobic bacteria (e.g., Anaerolineae) increased throughout the oasis profile.Furthermore, difference in fertilization and crop growth altered the organic carbon contents in the soil, which resulted in differences of microbial communities within oasis.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China.

ABSTRACT
The conversion of virgin desert into oasis farmland creates two contrasting types of land-cover. During oasis formation with irrigation and fertilizer application, however, the changes in the soil microbial population, which play critical roles in the ecosystem, remain poorly understood. We applied high-throughput pyrosequencing to investigate bacterial and archaeal communities throughout the profile (0-3 m) in an experimental field, where irrigation and fertilization began in 1990 and cropped with winter wheat since then. To assess the effects of cultivation, the following treatments were compared with the virgin desert: CK (no fertilizer), PK, NK, NP, NPK, NPKR, and NPKM (R: straw residue; M: manure fertilizer). Irrigation had a greater impact on the overall microbial community than fertilizer application. The greatest impact occurred in topsoil (0-0.2 m), e.g., Cyanobacteria (25% total abundance) were most abundant in desert soil, while Actinobacteria (26%) were most abundant in oasis soil. The proportions of extremophilic and photosynthetic groups (e.g., Deinococcus-Thermus and Cyanobacteria) decreased, while the proportions of R-strategy (e.g., Gammaproteobacteria including Xanthomonadales), nitrifying (e.g., Nitrospirae), and anaerobic bacteria (e.g., Anaerolineae) increased throughout the oasis profile. Archaea occurred only in oasis soil. The impact of fertilizer application was mainly reflected in the non-dominant communities or finer taxonomic divisions. Oasis formation led to a dramatic shift in microbial community and enhanced soil enzyme activities. The rapidly increased soil moisture and decreased salt caused by irrigation were responsible for this shift. Furthermore, difference in fertilization and crop growth altered the organic carbon contents in the soil, which resulted in differences of microbial communities within oasis.

No MeSH data available.