Weather is seldom "normal". Much of the time, it's either too wet or too dry, too hot or too cold for optimum corn growth. In some areas and under certain soil conditions, even average seasonal weather will produce stress in corn. Plant stress visually can be very obvious; but often it's so slight as to go unnoticed by the casual observer-until the yield results are in.
Stress may result from a number of factors. A shortage of plant water is by far the most frequently occurring and detrimental one within the Corn Belt, particularly the western part. However, excess moisture will also create a stress situation.
Adverse soil moisture and temperature conditions in combination with nutrient deficiencies, diseases, insects, and weeds interact to create many different kinds of crop stress. And proper diagnosis of such stress under field conditions is not a simple matter.
Solar radiation can also be an interactive stress factor, in spite of its critical role in plant photosynthesis. For example, in controlled experiments, increased radiation has been shown to increase corn yields if other factors are kept adequate. However, under field conditions in the western Corn Belt, high radiation is often associated with low rainfall and high evaporative demand, resulting in moisture stress that becomes the dominant factor in affecting final corn yield.
Two of the western Corn Belt's best yield years (1981 and 1982) were also years with low solar radiation. Would higher radiation have increased yields because of greater photosynthetic activity or reduced yields because of greater moisture stress? Such questions can be answered only if one understands the interactive effects of the different weather parameters.
This publication describes the various weather-induced stress conditions that affect the corn plant during each of its growth stages. Discussed are how the conditions develop, how they may be identified, and what their individual and interactive effects might be on final grain yield. Suggestions for minimising stress effects are also provided.
For more of the article, please click here
Article made possible through the contribution of Oklahoma State University.