The Impacts of Soil Fertility and Salinity on Soil Nitrogen Dynamics Mediated by the Soil Microbial Community Beneath the Halophytic Shrub Tamarisk
- 542 Downloads
Nitrogen (N) is one of the most common limiting nutrients for primary production in terrestrial ecosystems. Soil microbes transform organic N into inorganic N, which is available to plants, but soil microbe activity in drylands is sometimes critically suppressed by environmental factors, such as low soil substrate availability or high salinity. Tamarisk (Tamarix spp.) is a halophytic shrub species that is widely distributed in the drylands of China; it produces litter enriched in nutrients and salts that are thought to increase soil fertility and salinity under its crown. To elucidate the effects of tamarisks on the soil microbial community, and thus N dynamics, by creating “islands of fertility” and “islands of salinity,” we collected soil samples from under tamarisk crowns and adjacent barren areas at three habitats in the summer and fall. We analyzed soil physicochemical properties, inorganic N dynamics, and prokaryotic community abundance and composition. In soils sampled beneath tamarisks, the N mineralization rate was significantly higher, and the prokaryotic community structure was significantly different, from soils sampled in barren areas, irrespective of site and season. Tamarisks provided suitable nutrient conditions for one of the important decomposers in the area, Verrucomicrobia, by creating “islands of fertility,” but provided unsuitable salinity conditions for other important decomposers, Flavobacteria, Gammaproteobacteria, and Deltaproteobacteria, by mitigating salt accumulation. However, the quantity of these decomposers tended to be higher beneath tamarisks, because they were relatively unaffected by the small salinity gradient created by the tamarisks, which may explain the higher N mineralization rate beneath tamarisks.
KeywordsDryland Inorganic nitrogen dynamics Plant-soil interactions Saline soil Soil prokaryote community structure
We greatly thank the members of the Institute of Soil and Water Conservation of Chinese Academy of Sciences (CAS), the Arid Land Research Center (ALRC) of Tottori University, and the Field Science, Education and Research Center (FSERC) of Kyoto University, for cooperation and logistics in both field survey and laboratory analysis. We also greatly thank Dr. Kazuo Isobe for helpful comments.
This study was financially supported in part by JSPS-KAKENHI (Grant No. 15H05113), JSPS-NSFC Bilateral Joint Research Projects (Co-Principal Investigators: Norikazu Yamanaka and Du Sheng, NSFC Grant No. 41411140035, 41171419), Grant-in-Aid for JSPS Research Fellow (Grant No. 24-4309), and Fund of Joint Research Program of Arid Land Research Center, Tottori University.
- 24.Garner W, Steinberger Y (1989) A proposed mechanism for the formation of Fertile Islands in the desert ecosystem. J Arid Environ 16:257–262Google Scholar
- 28.Decker JP (1961) Salt secretion by Tamarix pentandra Pall. For Sci 7:214–217Google Scholar
- 34.Yang X, Zhu Z, Jaekel D, et al. (2002) Late Quaternary palaeoenvironment change and landscape evolution along the Keriya River, Xinjiang, China: the relationship between high mountain glaciation and landscape evolution in foreland desert regions. Quat Int 97–98:155–166. https://doi.org/10.1016/S1040-6182(02)00061-7 CrossRefGoogle Scholar
- 36.Cheng JM, Wan HE (2002) Vegetation construction and soil and water conservation in the Loess Plateau of ChinaGoogle Scholar
- 45.Suzuki MT, Giovannoni SJ (1996) Bias caused by template annealing in the amplification of mixtures of 16S rRNA genes. Appl Environ Microbiol 62:2–8Google Scholar
- 46.Wang Y, Qian P (2009) Conservative fragments in bacterial 16S rRNA genes and primer design for 16S ribosomal DNA amplicons in metagenomic studies. PLoS One. https://doi.org/10.1371/journal.pone.0007401
- 52.Fox J, Nie Z, Byrnes J (2017) sem: structural equation models. R package version 3.1-9. URL https://CRAN.R-project.org/package=sem
- 53.Fox J, Weisberg S, Adler D, et al (2014) Package “car” (Version 2.1-3). URL https://r-forge.r-project.org/projects/car/, https://CRAN.R-project.org/package=car, https://socserv.socsci.mcmaster.ca/jfox/Books/Companion/index.html
- 58.Cottrell MT, Kirchman DL (2000) Natural assemblages of marine proteobacteria and members of the Cytophaga-Flavobacter clustler consuming low- and high-molecular-weight dissolved organic matter. Appl Environ Microbiol 66:1692–1697. https://doi.org/10.1128/AEM.66.4.1692-1697.2000 CrossRefPubMedPubMedCentralGoogle Scholar
- 60.Padmanabhan P, Padmanabhan S, DeRito C, et al. (2003) Respiration of 13 C-labeled substrates added to soil in the field and subsequent 16S rRNA gene analysis of 13 C-labeled soil DNA. Appl Environ Microbiol 69:1614–1622. https://doi.org/10.1128/AEM.69.3.1614 CrossRefPubMedPubMedCentralGoogle Scholar
- 72.Xun W, Zhao J, Xue C, et al. (2016) Significant alteration of soil bacterial communities and organic carbon decomposition by different long-term fertilization management conditions of extremely low-productivity arable soil in South China. Environ Microbiol 18(6):1907–1917. https://doi.org/10.1111/1462-2920.13098 CrossRefPubMedGoogle Scholar
- 75.Sorokin DY, Tourova TP, Henstra AM, et al. (2008) Sulfidogenesis under extremely haloalkaline conditions by Desulfonatronospira thiodismutans gen. nov., sp. nov., and Desulfonatronospira delicat sp. nov.—a novel lineage of Deltaproteobacteria from hypersaline soda lakes. Microbiology 154:1444–1453. https://doi.org/10.1099/mic.0.2007/015628-0 CrossRefPubMedGoogle Scholar