Dunfield’s team investigated how agricultural management practices, particularly cover cropping and crop rotation diversity, affect soil health through changing microbial communities and soil organic matter. Using advanced techniques like DNA metabarcoding and soil carbon analysis, the project demonstrates that diversified cropping systems can enhance soil carbon storage and influence microbial community composition, ultimately contributing to more sustainable farming practices.
Soil microbial diversity plays a pivotal role in agricultural ecosystem health, orchestrating fundamental processes from nutrient cycling to climate adaptation. Traditional soil assessment methods have proven inadequate in capturing the sophisticated network of microbial interactions, and despite advances in molecular analysis techniques, scientists face challenges in connecting microbial patterns to tangible ecosystem outcomes. Research is needed to understand the complex interplay between agricultural management practices and soil microbial communities, examining how techniques such as cover cropping and crop rotation influence both soil chemistry and microbial dynamics, with the goal of enhancing agricultural sustainability through improved understanding of plant-soil-microbe relationships.
Research led by Dr. Kari Dunfield and her team supports the adoption of evidenced-based agricultural management practices. Through several case studies, Dunfield’s team used real in-field data combined with soil carbon analysis, DNA metabarcoding, and more to analyze important components such as impact of cover cropping and crop rotational diversity, on soil organic matter composition and stabilization, as well as soil microbial communities. Overall, these studies highlight the potential of diversified cropping systems and cover crops to improve soil health and carbon sequestration, while emphasizing the complex interactions between agricultural practices, soil properties, and microbial communities in shaping soil organic matter dynamics. stablish functional diversity.
The project uncovered several key insights into how cover cropping and diverse crop rotations impact soil health, particularly soil organic matter (SOM) and microbial communities. Findings consistently showed that incorporating a variety of crops and using cover crops can increase SOM levels, which plays a crucial role in long-term carbon storage and soil fertility. Additionally, molecular analyses revealed that greater crop diversity helps preserve organic matter in the soil, making nutrients more available to plants over time. The research also highlighted how cover crops and rotational diversity influence soil microbial populations, with certain crops fostering beneficial microbes that enhance soil function. However, the effects of cover crops on microbial communities were influenced by factors such as water availability and crop residue management, underscoring the complexity of soil ecosystems and the need for tailored farming practices. As for tillage, Dunfield’s team explored how different tillage practices (conventional vs. conservation) and nitrogen (N) fertilization rates affect soil carbon dynamics over 24 years in Southern Ontario. The research found that conservation tillage increased certain SOM components, such as lipids and sugars, compared to conventional tillage, regardless of N levels. These findings suggest that tillage practices are a more significant factor in soil carbon cycling than N fertilization, while conservation tillage aids in the break down of organic matter.
This research is crucial for producers and agricultural practices because it provides valuable insights into how farming techniques can directly influence soil health, carbon storage, and microbial communities—factors that are vital for long-term sustainability. By examining practices like cover cropping, crop rotation, and tillage methods, Dr. Kari Dunfield’s team highlights how these techniques can improve soil organic matter, enhance nutrient availability, and promote beneficial soil microbes, which are all key to increasing crop yields and resilience. As producers look to research to validate recommendations for environmentally beneficial practices, this research contributes to a better understanding of the merits and effects of recommended management practices. Evidence-based research that demonstrates the relationship between soil management and microbial diversity can help farmers make informed decisions that support productivity, reduce environmental impacts, and improve the overall sustainability of their operations. Finally, Dunfield’s team underscored the importance of adopting tailored farming practices to account for the complexity of soil ecosystems and regional contexts, ensuring that farmers can optimize their methods with practices suited to their context and growing conditions.
Man, M., Tosi, M., Dunfield, K. E., Hooker, D. C., & Simpson, M. J. (2022). Tillage management exerts stronger controls on soil microbial community structure and organic matter molecular composition than N fertilization. Agriculture, Ecosystems & Environment, 336, 108028. https://doi.org/10.1016/j.agee.2022.108028
Obregon, D., Mafa-Attoye, T. G., Baskerville, M., Mitter, E. K., De Souza, L. F., Oelbermann, M., Thevathasan, N. V., Tsai, S. M., & Dunfield, K. E. (2023). Functionality of methane cycling microbiome during methane flux hot moments from riparian buffer systems. Science of The Total Environment, 870, 161921. https://doi.org/10.1016/j.scitotenv.2023.161921
Obregon Alvarez, D., Fonseca de Souza, L., Mendes, L. W., De Moraes, M. T., Tosi, M., Venturini, A. M., Meyer, K. M., Barbosa de Camargo, P., Bohannan, B. J. M., Mazza Rodrigues, J. L., Dunfield, K. E., & Tsai, S. M. (2023). Shifts in functional traits and interactions patterns of soil methane‐cycling communities following forest‐to‐pasture conversion in the Amazon Basin. Molecular Ecology, 32(12), 3257–3275. https://doi.org/10.1111/mec.16912
Tong, H., Man, M., Wagner-Riddle, C., Dunfield, K. E., Deen, B., & Simpson, M. J. (2023). Crop rotational diversity alters the composition of stabilized soil organic matter compounds in soil physical fractions. Canadian Journal of Soil Science, 103(1), 213–233. https://doi.org/10.1139/cjss-2022-0058
Tosi, M., Drummelsmith, J., Obregón, D., Chahal, I., Van Eerd, L. L., & Dunfield, K. E. (2022). Cover crop-driven shifts in soil microbial communities could modulate early tomato biomass via plant-soil feedbacks. Scientific Reports, 12(1), 9140. https://doi.org/10.1038/s41598-022-11845-x
Tosi, M., Ogilvie, C. M., Spagnoletti, F. N., Fournier, S., Martin, R. C., & Dunfield, K. E. (2023). Cover Crops Modulate the Response of Arbuscular Mycorrhizal Fungi to Water Supply: A Field Study in Corn. Plants, 12(5), 1015. https://doi.org/10.3390/plants12051015
