This project was part of the graduate research for master’s student Tindall Ouverson, and is her first manuscript!
Tindall is a Master’s of Science in the Department of Land Resources and Environmental Sciences at Montana State University. Her graduate advisers are Drs. Fabian Menalled and Tim Seipel. Her research focuses on the response of soil microbial communities to cropping systems and climate change in semiarid agriculture.
I have been mentoring Tindall as a graduate committee member since she began in fall 2019, teaching her laboratory and analytical skills in microbial ecology, DNA sequencing, and bioinformatic analysis. We first met when she came to visit when I was working in Oregon, and since then have connected remotely. She has a flair for bioinformatics analysis, and a passion for sustainable agricultural development. She plans to defend her thesis in spring 2021, and then to further her career in sustainable agriculture in Montana.
In the Northern Great Plains of the United States, cereal crops, such as wheat, are important economic staples. In this area, climate change is forecasted to increase temperature and decrease precipitation during the summer, which is expected to negatively affect crop production and the management of pests (insects and microbes). There are numerous reports on the current effects of climate change on agricultural production, as well as how they will be predicted to worsen, such as:
- Soil bacterial communities of wheat vary across the growing season and among dryland farming systems.
- Agroecosystem resilience is modified by management system via plant soil feedbacks.
- Weed communities and wheat yield are modified by cropping systems and climate conditions. In review.
Ouverson, T., Eberly, J., Seipel, T., Menalled, F., Ishaq, S.L.. 2021.Temporal soil bacterial community responses to cropping systems and crop identity in dryland agroecosystems of the Northern Great Plains. Frontiers in Sustainable Food Systems 5:75. No Impact Factor. Article. This is an invited submission to Plant Growth-Promoting Microorganisms for Sustainable Agricultural Production special collection.
Abstract
Industrialized agriculture results in simplified landscapes where many of the regulatory ecosystem functions driven by soil biological and physicochemical characteristics have been hampered or replaced with intensive, synthetic inputs. To restore long-term agricultural sustainability and soil health, soil should function as both a resource and a complex ecosystem. In this study, we examined how cropping systems impact soil bacterial community diversity and composition, important indicators of soil ecosystem health. Soils from a representative cropping system in the semi-arid Northern Great Plains were collected in June and August of 2017 from the final phase of a five-year crop rotation managed either with chemical inputs and no-tillage, as a USDA-certified organic tillage system, or as a USDA-certified organic sheep grazing system with reduced tillage intensity. DNA was extracted and sequenced for bacteria community analysis via 16S rRNA gene sequencing. Bacterial richness and diversity decreased in all farming systems from June to August and was lowest in the chemical no-tillage system, while evenness increased over the sampling period. Crop species identity did not affect bacterial richness, diversity, or evenness. Conventional no-till, organic tilled, and organic grazed management systems resulted in dissimilar microbial communities. Overall, cropping systems and seasonal changes had a greater effect on microbial community structure and diversity than crop identity. Future research should assess how the rhizobiome responds to the specific phases of a crop rotation, as differences in bulk soil microbial communities by crop identity were not detectable.