Anaerobic soil environments
Water-logged soil will have spaces for oxygen molecules to support uptake of this important element needed for cellular respiration. The few bacteria that can survive these environments without free oxygen gas have another method of obtaining oxygen from compounds as nitrate (NO3). These bacteria take away an oxygen atom to reduce it to NO2, and then continue to reduce to NO and finally the gas N2.
This process not only reduces the nitrate available for eventual absorption in the root tissue as the N2 gas is not absorbed in corn roots but also will escape into the surrounding air. Not only does the wet pond in the field reduce root growth but also can lead to eventual nitrate reduction needed for plant growth after the flooding subsides.
Pythium, a genus of organisms that appear like a fungus but is classified in a separate group called Oomycetes. This group of organisms feature production of an overwintering spore (oospore) that germinates in water with production of swimming spores called zoospores. They swim towards root tissue. After attaching, it produces filaments penetrating the root. The host supplies nutrition to the pathogen, allowing it to eventually produce more oospores. Pythium species can kill the corn seedling.
The multiple dynamics of rain amounts, soil types, drainage, corn growth stage and multiple organisms in the soil influence the affect of early season flooding in corn fields.
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About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.