Corn Growth

Soil Microbial Communities and Early Season Corn Growth

The soil microbial community plays many roles in the soil. Although some microbes are pathogens, most are beneficial. Soil organisms are important for nutrient cycling, nutrient retention, improved soil structure, water infiltration and water-holding capacity, disease suppression, degradation of pollutants and soil biodiversity. Soil microbial communities contain various types of organisms: fungi, bacteria, protozoa, microarthropods and nematodes. These organisms form a foodweb. There are multiple methods of characterizing these organisms; they can be counted, or quantified by their activity or cellular constituents. An overview of soil microbes and their roles will be provided as well as an introduction to methods for studying microbes. Management can impact the soil community directly and indirectly. During the early growing season, soils tend to be cool and wet, which impacts growing conditions of the microbes and plants. Cool temperatures can change the material exuded from corn roots into the soil. Planting too early can result in poor germination. Corn will germinate and grow at 50oF but does better when average air-temperatures are 55oF. Plant roots both influence the microbial community and are affected by microbes. Examples of how environmental conditions, soil microbes and plant roots interact will be presented.

Jane Johnson USDA-ARS
jjohnson@morris.ars.usda.gov

Biography:  A native of Minnesota I was raised on a mixed rotation, small dairy farm in West Central, MN. I have a BA in Biology/minor Chemistry. I worked for several years as a technician at the North Central Soil Conservation Research Laboratory, USDA-ARS, Morris MN on corn and soybean response to high-axle load traffic. I attended graduate school at University of Minnesota receiving a MS in Soil Science, my theses titled ‘Soil Physical and Crop Response to High Axle Load Wheel Traffic and Subsoil Tillage’, 1990 and receiving a PHD in Plant Biology, theses titled ‘Biochemical, metabolic, and developmental Adaptations in White Lupin Roots in Response to Phosphorus Stress’. 1995. I taught for four years in the Department of Biology, University of Wisconsin-Stevens Point, teaching Plant Physiology and general Biology. In 2000, I accepted a position at North Central Soil Conservation Research Laboratory, USDA-ARS, Morris MN as Plant and Soil Biochemist. My research in Morris is in several inter-related areas – concerning carbon partitioning, above and below ground plant composition in response to environmental stress (e.g. temperature), carbon sequestration, trace gas emissions, C and N cycling, role of biomass for energy and impacts on soil quality and productivity.