Farmers are facing new challenges in the age of global change. Drought is a major stressor for crops in Indiana and other regions of the U.S. and is forcing farmers to face the question: to irrigate or not to irrigate? Irrigation equipment is incredibly expensive, but is often the best quick solution to water crops and guarantee their survival during the growing season. Research in the Lau lab may be able to provide some answers about the effects of irrigation on plant survival under drought stress and how microbes may be another important player in this story.
Dr. Jen Lau is an associate professor in the Department of Biology and a recent hire at IU as part of the Environmental Resilience Institute (ERI). The ERI, an institute established by the Grand Challenge proposal “Preparing for Environmental Change”, is working to incorporate integrative, cross-field research and strategies to prepare Indiana for environmental change. Lau was a great fit for the institute: her lab focuses on questions related to evolutionary and community ecology, with a specific emphasis on plant fitness in the face of climate change.
Part of the Lau lab’s research has shifted to focus on plant and microbe interactions, especially in relation to environmental stressors that are linked to climate change. Conducting a greenhouse project in collaboration with Dr. Jay Lennon was a driving force behind that shift. Plants were grown individually in a mesocosm, a highly-controlled setting that incorporated soil collected from either wet or dry environments. Then, plants were either exposed to drought conditions or not, which is as simple as it sounds: Lau and Lennon didn’t water some plants as effectively as the others. Since the soils used were from natural environments, they included the natural microbial communities of those environments. This enabled Lau and Lennon to investigate whether the types of microbes present in these soils affected their interactions with their co-habitating plants.
While the experiment seemed simple at the time, the results were rewarding. Microbes from dry environments protected the plants from drought stress by diminishing the negative effects of drought on plant fitness, which was measured by the number of seeds the plants produced. Drought stress only reduced seed production by about 20% in plants with dry-environment microbes. In contrast, drought caused plants grown with wet-environment microbes to reduce seed production by 60%. Lau and Lennon attributed this substantial difference in plant fitness to the different microbial communities present in the soils.
But of course, this project was executed in a very simplified environment. Would these patterns hold true in the field? One of Lau’s graduate students, Lana Bolin, designed an experiment that tested soils from a long-term irrigation experiment, which included irrigated and unirrigated samples collected over the past decade from plots at Michigan State University’s Kellogg Biological Station. Bolin used these samples to treat soybean plants grown in the field. She created innovative blockades to prevent water from reaching plants under “drought stress” and supplemented watering for plants in the control group, which received no drought stress. Although the data are still being analyzed, her preliminary results support Lau and Lennon’s findings in the greenhouse: microbes matter, and the soil conditions that these microbes adapt to affects how much they can help plants. While these results suggest that microbes could play a role in mitigating the effects of drought stress, there are still a lot of questions to be answered.
Lau recently formed a new collaboration with Dr. Matt Houser, an ERI fellow in the Department of Sociology. Houser works with farmers across Indiana and studies their decision-making processes when faced with demanding environmental conditions, such as drought. Lau plans to perform additional experiments using farmers’ fields to assess how microbial communities vary across different farms that use irrigation and whether other management options (e.g., cover crops or no-till) might promote microbial communities that better buffer crops from drought stress.
Lau is not suggesting that farmers stop irrigating their fields in the face of high drought stress, since irrigation is a good solution to seasonal drought, especially in the short-term. “I don’t know if microbes are going to make a difference in the bigger picture,” says Lau, “but if they do, there are easy things we can do to facilitate [the process]… if [farmers] can build resilience by cultivating the right type of microbial community, it may be cheaper for them in the long run, and it might buffer them from further environmental change.” Although Lau’s lab works on basic scientific research, her work with Dr. Matt Houser and the farmers of Indiana, in addition to other ERI efforts, could help further prepare Indiana for environmental change.