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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.


Relative abundances of selected microbial taxa at 0.2–0.6 and 0.6–3 m depths in desert and oasis soils.Desert: the original soil from which the oasis was derived; No fertilizer: the control (CK); Fertilizer: the average values of six fertilizer treatments (PK, NK, NP, NPK, NPKR, and NPKM). Deinococcus = Deinococcus-Thermus. Values at each depth are weighted means. For each microbial taxon, values for different depths within same treatment followed by the same uppercase letter are not significantly different (p >0.05); treatment means within same depth followed by the same lowercase letters are not significantly different (p >0.05).
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pone.0139626.g003: Relative abundances of selected microbial taxa at 0.2–0.6 and 0.6–3 m depths in desert and oasis soils.Desert: the original soil from which the oasis was derived; No fertilizer: the control (CK); Fertilizer: the average values of six fertilizer treatments (PK, NK, NP, NPK, NPKR, and NPKM). Deinococcus = Deinococcus-Thermus. Values at each depth are weighted means. For each microbial taxon, values for different depths within same treatment followed by the same uppercase letter are not significantly different (p >0.05); treatment means within same depth followed by the same lowercase letters are not significantly different (p >0.05).

Mentions: As soil depth increased, the relative abundance of Cyanobacteria and Actinobacteria rapidly decreased, but the abundance of Proteobacteria, especially γ-proteobacteria significantly increased and became the overwhelmingly dominant population in the deep soil for both desert and oasis (Fig 3). The frequencies and abundances of finer taxonomic divisions (e.g., the orders Pseudomonadales, Oceanospirillales, and Enterobacteriales within the γ-proteobacteria) also increased correspondingly with depth (Table 3). Irrigation also had a significant impact on the microbial communities below the topsoil. And the response of most microbial taxa below the topsoil was similar to that in topsoil (Table 3 and Fig 3). However, the responses of some microbial populations were different, e.g., decreases in the proportions of Actinobacteridae, Acidimicrobidae (Table 3), and δ-proteobacteria (Fig 3) below the topsoil, which contrasted with their increases in topsoil, in the oasis comparing to the desert.


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

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

Relative abundances of selected microbial taxa at 0.2–0.6 and 0.6–3 m depths in desert and oasis soils.Desert: the original soil from which the oasis was derived; No fertilizer: the control (CK); Fertilizer: the average values of six fertilizer treatments (PK, NK, NP, NPK, NPKR, and NPKM). Deinococcus = Deinococcus-Thermus. Values at each depth are weighted means. For each microbial taxon, values for different depths within same treatment followed by the same uppercase letter are not significantly different (p >0.05); treatment means within same depth followed by the same lowercase letters are not significantly different (p >0.05).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0139626.g003: Relative abundances of selected microbial taxa at 0.2–0.6 and 0.6–3 m depths in desert and oasis soils.Desert: the original soil from which the oasis was derived; No fertilizer: the control (CK); Fertilizer: the average values of six fertilizer treatments (PK, NK, NP, NPK, NPKR, and NPKM). Deinococcus = Deinococcus-Thermus. Values at each depth are weighted means. For each microbial taxon, values for different depths within same treatment followed by the same uppercase letter are not significantly different (p >0.05); treatment means within same depth followed by the same lowercase letters are not significantly different (p >0.05).
Mentions: As soil depth increased, the relative abundance of Cyanobacteria and Actinobacteria rapidly decreased, but the abundance of Proteobacteria, especially γ-proteobacteria significantly increased and became the overwhelmingly dominant population in the deep soil for both desert and oasis (Fig 3). The frequencies and abundances of finer taxonomic divisions (e.g., the orders Pseudomonadales, Oceanospirillales, and Enterobacteriales within the γ-proteobacteria) also increased correspondingly with depth (Table 3). Irrigation also had a significant impact on the microbial communities below the topsoil. And the response of most microbial taxa below the topsoil was similar to that in topsoil (Table 3 and Fig 3). However, the responses of some microbial populations were different, e.g., decreases in the proportions of Actinobacteridae, Acidimicrobidae (Table 3), and δ-proteobacteria (Fig 3) below the topsoil, which contrasted with their increases in topsoil, in the oasis comparing to the desert.

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.