Soil Bacterial Community Diversity and Composition as Affected by Tillage Intensity Treatments in Corn-Soybean Production Systems

Abstract

Our understanding on the effects of tillage intensity on the soil microbial community structure and composition in crop production systems are limited. This study evaluated the soil microbial community composition and diversity under different tillage management systems in an effort to identify management practices that effectively support sustainable agriculture. We report results from a three-year study to determine the effects on changes in soil microbial diversity and composition from four tillage intensity treatments and two residue management treatments in a corn-soybean production system using Illumina high-throughput sequencing of 16S rRNA genes. Soil samples were collected from tillage treatments at locations in the Southern Coastal Plain (Verona, Mississippi, USA) and Southern Mississippi River Alluvium (Stoneville, Mississippi, USA) for soil analysis and bacterial community characterization. Our results indicated that different tillage intensity treatments differentially changed the relative abundances of bacterial phyla. The Mantel test of correlations indicated that differences among bacterial community composition were significantly influenced by tillage regime (rM = 0.39, p ≤ 0.0001). Simpson’s reciprocal diversity index indicated greater bacterial diversity with reduction in tillage intensity for each year and study location. For both study sites, differences in tillage intensity had significant influence on the abundance of Proteobacteria. The shift in the soil bacterial community composition under different tillage systems was strongly correlated to changes in labile carbon pool in the system and how it affected the microbial metabolism. This study indicates that soil management through tillage intensity regime had a profound influence on diversity and composition of soil bacterial communities in a corn-soybean production system.

Effects of tillage and biochar on soil physiochemical and microbial properties and its linkage with crop yield

“…Meanwhile, SOC, a vital source in the microbially driven carbon cycle, was mainly distributed in the topsoil, and therefore, the changes in pH and SOC are more associated with the soil bacteria ( Puissant et al, 2015 ; Cao et al, 2016 ). The studies have identified the soil pH and tillage as important factors determining the distribution pattern of microorganisms ( Xia et al, 2020 ; Shanmugam et al, 2021 ). The soil pH was an important factor that influenced the structure and diversity of soil metabolism and bacterial community ( Siles and Margesin, 2016 ; Cheng et al, 2020 ).…”

“…Thus, the bacterial community composition of the bottom soil also changed. On the contrary, tillage might have reduced the habitat heterogeneity, favoring few bacteria and helping them outgrow other competitors; this eventually changed the bacterial community ( Shanmugam et al, 2021 ), by altering the chemical properties.…”

Reduced Tillage Increases Soil Biological Properties But Not Suppressiveness Against Rhizoctonia Solani and Streptomyces Scabies

“…On the other hand, there are indications that an increase of these genera is more directly linked to tillage. Actinobacteria and specifically members of the genus Streptomyces were found to be increased in abundance under reduced tillage regimes, which was likely due to increased residues of organic material on the soil surface (Shanmugam et al, 2021;Zaitlin et al, 2004). Also, Lysobacter has been found to be increased in abundance under non-inversion tillage and was positively correlated to the C/N ratio (Sun et al, 2020).…”

The Role of Soil Microbial Consortia in Sustainable Cereal Crop Residue Management

“…In line with this, a study found that after two years, the remaining biomass of 14C-labelled wheat residue was significantly lower under conventional tillage (25.8%) compared to reduced tillage (40.0%), corroborating the hypothesis that conventional tillage accelerates residue decomposition [ 68 ]. However, it is important to note a general trend of diminished bacterial diversity associated with conventional tillage [ 69 , 70 , 71 ]. Interestingly, Duan and colleagues [ 72 ] suggest that the increase in alpha diversity observed under conventional tillage might result from the disturbance of soil aggregate stability and the subsequent release of physically protected organic matter, which is then utilized by microbes.…”