Abstract
Continuous monocropping poses a major threat to soil health and crop productivity, yet its effects on the rhizosphere microbiome of autoflowering hemp remain largely unexplored. Here, we integrated high-throughput sequencing (HTS) and community-level physiological profiling (CLPP) to investigate how two successive growth cycles of continuous cropping (CC) influence rhizosphere bacterial communities, functional potential, and plant physiological performance in Cannabis sativa L. (cv. Orange Candy). CC markedly altered bacterial community composition, reducing the abundance of oligotrophic and decomposer-associated taxa such as Actinobacteria, Chloroflexi, Acidobacteria. Class-level co-occurrence networks showed variation in the proportion of positive and negative associations across treatments, with CC exhibiting a moderate presence of negative interactions, suggesting shifts in microbial interaction structure. Despite these compositional changes, bacterial richness and Shannon diversity increased under CC, suggesting expansion of ecological niches rather than a loss of diversity. CLPP analysis showed that CC soils maintained high metabolic activity and functional evenness, with substrate utilization patterns diverging from uncultivated and first-cropping treatments. Importantly, CC negatively affected key plant traits including plant height, biomass, and bud yield, which were positively associated with bacterial genera such as Rhodoplanes, Actinomadura, Devosia, and Kribbella. Together, these findings reveal a paradoxical pattern in which continuous hemp cultivation increases microbial diversity and functional activity while coinciding with reduced plant performance, consistent with negative plant–soil feedback. This study highlights the importance of rhizosphere microbial dynamics in shaping plant productivity and underscores the need for microbial management strategies to sustain industrial hemp agroecosystems.
Advisor
Timothy Secott
Committee Member
Christopher Ruhland
Committee Member
Mriganka De
Committee Member
Cecilia Noecker
Date of Degree
2026
Language
english
Document Type
Thesis
Degree
Master of Science (MS)
Program of Study
Biology
Department
Biological Sciences
College
Science, Engineering and Technology
Recommended Citation
Afari, E. G. (2026). Effects of continuous cropping of autoflowering hemp on rhizosphere soil microbial communities and plant physiology [Master’s thesis, Minnesota State University, Mankato]. Cornerstone: A Collection of Scholarly and Creative Works for Minnesota State University, Mankato. https://cornerstone.lib.mnsu.edu/etds/1601/
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
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