Subsoil Microbial Diversity and Stability in Rotational Cotton Systems

Author(s)
Polain, Katherine
Knox, Oliver
Wilson, Brian
Pereg, Lily
Publication Date
2020-07-25
Abstract
Microbial diversity has been well documented for the top 0-0.30 m of agricultural soils. However, spatio-temporal research into subsoil microbial diversity and the effects of agricultural management remains limited. Soil type may influence subsoil microbial diversity, particularly Vertosols. These soils lack distinct horizons and are known to facilitate the downward movement of organic matter, potentially supporting subsoil microbiota, removed from the crop root system (i.e., bulk soils). Our research used the MiSeq Illumina Platform to investigate microbial diversity down the profile of an agricultural Australian Vertosol to 1.0 m in bulk soils, as influenced by crop system (continuous cotton and cotton-maize) and sample time (pre- and in-crop samples collected over two seasons). Overall, both alpha- (Chao1, Gini-Simpson Diversity and Evenness indices) and beta-diversity (nMDS and Sørensen's Index of Similarity) metrics indicated that both bacterial (16S) diversity and fungal (ITS) diversity decreased with increasing soil depth. The addition of a maize rotation did not significantly influence alpha-diversity metrics until 0.70-1.0 m depth in the soil, where bacterial diversity was significantly higher in this system, with beta-diversity measures indicating this is likely due to root system differences influencing dissolved organic carbon. Sample time did not significantly affect bacterial or fungal diversity over the two seasons, regardless of the crop type and status (i.e., crop in ground and post crop). The relatively stable subsoil fungal and overall microbial diversity in bulk soils over two crop seasons suggests that these microbiota have developed a tolerance to prolonged agricultural management.
Citation
Soil Systems, 4(3), p. 1-18
ISSN
2571-8789
Link
Publisher
MDPI AG
Rights
Attribution 4.0 International
Title
Subsoil Microbial Diversity and Stability in Rotational Cotton Systems
Type of document
Journal Article
Entity Type
Publication

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