Tillage Changes Vertical Distribution of Soil Bacterial and Fungal Communities

Abstract

Tillage can strongly affect the long-term productivity of an agricultural system by altering the composition and spatial distribution of nutrients and microbial communities. The impact of tillage methods on the vertical distribution of soil microbial communities is not well understood, and the correlation between microbial communities and soil nutrients vertical distributions is also not clear. In the present study, we investigated the effects of conventional plowing tillage (CT: moldboard plowing), reduced tillage (RT: rotary tillage), and no tillage (NT) on the composition of bacterial and fungal communities within the soil profile (0–5, 5–10, 10–20, and 20–30 cm) using high-throughput sequencing of the microbial 16S/ITS gene. Microbial communities differed by soil properties and sampling depth. Tillage treatment strongly affected the microbial community structure and distribution by soil depth, and changed the vertical distribution of soil bacterial and fungal communities differently. Depth decay of bacterial communities was significantly smaller in CT than in RT and NT, and that of fungal communities were significantly greater in RT than CT and NT. The presence/absence of species was the main contributing factor for the vertical variation of bacterial communities, whereas for fungal communities the main factor was the difference in relative abundance of the species, suggesting niche-based process was more important for bacterial than fungal community in structuring the vertical distribution. Soil total carbon was correlated more with soil bacterial (especially the anaerobic and facultatively anaerobic groups) than with fungal community. These results suggested different roles of bacteria and fungi in carbon sequestration of crop residue and in shaping soil carbon distribution, which might impact on soil fertility.

Bacterial community composition under long‐term reduced tillage and no till management

“…Both the Dong et al (2017) and Sengupta and Dick (2015) study sites had silt loam soils, while soils in the current study ranged from a very fine sandy loam at one end of the field to a silty clay loam at the other, with veins of clay soil running through 12 of the 24 plots (six no till and six reduced till). Similar to the current study, Sun et al (2018) also found bacterial OTU richness was greater in conventional and rotary tillage compared to no till soil. A potential reason for this decrease in diversity could be the release of nutrients from decomposing crop residues on the soil surface, promoting the proliferation of bacterial groups involved in organic matter breakdown.…”

“…Similar to the current study, Sun et al . () also found bacterial OTU richness was greater in conventional and rotary tillage compared to no till soil. A potential reason for this decrease in diversity could be the release of nutrients from decomposing crop residues on the soil surface, promoting the proliferation of bacterial groups involved in organic matter breakdown.…”

“…However, these techniques may not have a high enough resolution to discern shifts in low abundance community members at finer taxonomic scales, as it is estimated that a single gram of soil can contain several thousand bacterial species (Schloss and Handelsman 2006;Roesch et al 2007). As such, many studies in recent years have utilized various highthroughput sequencing approaches, including 16S rRNA amplicon sequencing, to elucidate effects of different agricultural management practices on microbial soil communities in greater taxonomic detail (Sengupta and Dick 2015;Dong et al 2017;Sun et al 2018). Experimental plots established by Locke et al (2013) have been maintained under the same tillage (reduced tillage) and no till conditions since the conclusion of that study, providing the opportunity to determine if changes in the soil microbial community are more apparent after a longer period of no till management.…”

Long-Term Phytoremediation of Coastal Saline Soil Reveals Plant Species-Specific Patterns of Microbial Community Recruitment

“…Analysis of the high-throughput sequencing data. The bioinformatic analyses were performed mainly with QIIME (Quantitative Insights Into Microbial Ecology, version 1.9.1) (58) according to the methods described in a previous study (59). In brief, the barcode sequences and adapter sequences and 55 bases of low quality at the end of the reads were discarded.…”

Community structure of soil fungi in a novel perennial crop monoculture, annual agriculture, and native prairie reconstruction

“…on which sustainability relies [9,10], so understanding community differences among agricultural and natural systems is critical to increase sustainability. Agricultural systems implement many cropping practices that act as abiotic and biotic filters of microbial communities [11][12][13][14]. Repeated soil disturbance, such as in a conventionally tilled agriculture system, often leads to changes in the diversity and overall community structure of soil communities [11,15].…”