Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 15, 2004
Publication Date: December 15, 2004
Citation: Johnson, J.M. 2004. Soil microbial communities and early season corn growth. In: Vyn, T.J., editor. Proceedings of the Indiana Certified Crop Adviser Program, December 14-15, 2004, Indianapolis, Indiana. 2004 CDROM.
Interpretive Summary: Spring planting season is a very busy time for farmers. As a result, farmers are trying to get into the field to begin spring planting operations as early as possible. However, planting early into cool, wet soil can result in poor germination and emergence. The reasons for poor germination and emergence are in part to interaction with soil organisms. Cool, wet conditions limit plant growth; favor some pathogenic bacteria and fungi increasing seed and root rots. Understanding the complexity of soil organisms is a first step in understanding how management decision can be modified to enhance beneficial organisms while discouraging disease causing microbes. An introduction to soil biology as it interacts with production agriculture is present. This information targets certified crop advisors to help them understand and advise farmers on management decisions and how those decisions may impact microbes 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 contribute to 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. Plant roots both influence the microbial community and are affected by microbes. 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 50 deg F but does better when average air-temperatures are 55 deg F. Examples of how environmental conditions, soil microbes and plant roots interact will be presented.