Soil Microbiology
If you wish information on specific programs or wish to learn of openings for new students in individual laboratories, please contact professors directly.
Study of microorganisms and enzymes present in soils and their activities bearing on soil fertility, plant growth, and the decomposition of organic residues and environmental pollutants.
Why an interest in Soil Microbiology and Biochemistry?
Involves a food web where smaller organisms are food sources for larger organisms. Microbes are the starting point of most food chains with protozoa, nematodes, rotifers, etc. feeding on microbes, and then larger organisms feeding on these smaller organisms. The process continues until the top of the food chain is reached.
Controls nutrient flow to plants through symbiotic relationships, such as nitrogen fixation (bacterial-plant symbiosis), mycorrhizae (fungal-plant symbiosis), and lichens (fungal-plant symbiosis).
Involves plant, animal, and human diseases, such as powdery mildew (fungus) or tetanus (bacteria).
Controls nutrient cycling in C, N, S, and other cycles. Without this cycling of nutrients, plants could no longer grow and animals that eat plants would cease to exist.
Involves degradation and reduction of organic pollutants from the environment, such as pesticides, human organic wastes, petroleum spills, and many others.
Produces pollutants, both inorganic and organic. Inorganic products such as nitrate can enter groundwater (nitrification) and nitrous oxide (N2O) (denitrification) can diffuse into the stratosphere where it reacts with ozone (O3) and can lead to enhanced UV exposure to humans and increased cases of skin cancer. Organic products such as geosims, produced by actinomycetes, can alter the taste of drinking water.
Involves genetically engineered organisms and their impact on soil, crops, and the environment.
acillus cereus var. mycoides isolated from soybean rhizosphere. Arabinose biosensor Pseudomonas fluorescens strain A506 (pAraLHB) in the barley rhizosphere. Green cells indicate available arabinose (Green fluorescent protein, Gfp). Red cells indicate the distribution of biosensor cells (red fluorescent protein, DsRed).
Vesicles of endomycorrhizae fungi stained in the soybean root
Programs Available in Soil Microbiology and Biochemistry:
Cambardella, Cynthia A. Associate Professor (USDA Collaborator). Soil microbiology and biochemistry, especially as they relate to processes controlling the turnover of C, N, P, and S in managed and natural ecosystems. Current research focuses on the dynamics of N cycling in soil as influenced by agricultural management practices and land use patterns. cindyc@nstl.gov
Castellano, Michael Assistant Professor. Soil biogeochemistry with particular focus on nitrogen. Cycling and transport of nitrogen and carbon in solid, solution and gaseous phases. Biogeochemical cycling as affected by soil water. castelmj@iastate.edu
Loynachan, Thomas E. Professor. Microbial ecology in soil and interactions with higher plants: Bradyrhizobium and Rhizobium ecology and survey/ecology of endomycorrhizae of Iowa soils. teloynac@iastate.edu
Moorman, Thomas B. Associate Professor (USDA Collaborator). Research emphasizes the microbial processes and ecological relationships which affect environmental impacts of farming systems. Current projects are assessing the relationship between microorganism distributions and the bioavailability and transformations of pesticides in soils, subsoils and riparian sediments. Other projects are examining the relationship between carbon sources and denitrification in subsoils and the fate of bacterial pathogens in land-applied swine manure. moorman@nstl.gov
Tabatabai, M. Ali. Professor. Soil enzymes; chemistry and biochemistry of nitrogen, sulfur, and phosphorus reactions and transformations in soils; analytical methods for soils, plant materials, and waters; land application of wastes; and chemistry of heavy metals in soils. malit@iastate.edu