Artificial Soils: Creating Matrices to Analyze the Effects of Matrix Properties on Microbial Behaviors

Many aspects of plant and microbial behaviors may be altered by the physical properties of their soil environment.  Because many biological processes are triggered only when a threshold chemical concentration is reached and soil properties can alter the bioavailable concentration of chemicals, there is a need to study bacteria and plant behaviors in their environmental context to account for how the physical and chemical characteristics of soil change the ability of plants and microbes to engage in a wide range of behaviors, including intercellular communication. However, the extraordinarily high complexity of natural soils makes it challenging to design experiments that allow us to understand which specific soil properties (e.g., particle size, mineral composition, and organic matter content) act to control various plant and microbial behaviors.

In the lab, we construct fully sterilizable artificial soils to analyze microbial behaviors in environments that are more complex than liquid media but less complex than natural soils. Using a flexible "recipe" devised by several lab group members, we can independently vary factors such as mineral composition, pH, organic matter content, degree of aggregation, and degree of nutrient spatial heterogeneity in our soils. We also characterize these soils, describing their physical (water retention curve, surface area) and chemical (pH and cation exchange capacity) characteristics

These artificial soils have a wide range of applications, and the development of highly customizable and well-characterized matrices will be useful for providing information on questions such as the ecological effects of soil amendments and fertilizers, controlling pests, and enhancing beneficial microbial activities such as biological nitrogen fixation.

(information on requesting a sample/AS recipe)