Human Activity Affecting Microbes in Soil

New research from an Iowa State University ecologist shows that agricultural inputs such as nitrogen and phosphorous alter soil microbial communities, which may have unintended environmental consequences.

Adding nitrogen and phosphorous, commonly used as fertilizers, to the soil beneath grasslands shifts the natural communities of fungi, bacteria and microscopic organisms called archaea that live in the soil, said Kirsten Hofmockel, an associate professor in the ISU Department of Ecology, Evolution and Organismal Biology.

For instance, some soil microbes change the form of nitrogen in the soil. Ammonia-oxidizing archaea feed on ammonia and then convert it into nitrate. Hofmockel said the research shows that those ammonia oxidizers grow as more nitrogen is introduced, essentially because those organisms have access to more food. As a consequence, increasing amounts of nitrate may leach into waterways.

Generally, the researchers found nutrient additions favored fast-growing bacteria and decreased the abundance of fungi that share a symbiotic relationship with grassland plants.

For further details see: “Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe.”



Posted by Dr. Tim Sandle