In general, the 1998 growing season was very difficult for corn growers. Excessive winter and spring rains delayed most plantings and greatly delayed plantings on clay soils and poorly drained areas. Cool temperatures and spring rains brought on weed problems.
Temperatures were below normal through July. August was characterized by periods of hot and cool temperatures. In August there were nine days of 100ºF or higher.
In general, yields were disappointing particularly the May plantings. There were some above average yields from March and April plantings. Ear heights were higher than normal and lodging was a problem in many fields. The major diseases, fusarium ear rot, maize dwarf mosaic, and common smut were below normal. Spider mite populations were lower than normal, particularly early in the season.

This report contains cultural information and the results of field corn trials conducted in Yolo and Solano counties in 1997 and 1998.
Natural variation in fertility, moisture supply, and many other factors may account for part of the differences in yield observed between varieties or treatments in a trial. Because of this variation, small differences in yield may have little meaning. The yield differences in pounds per acre between varieties or treatments required for significance at the 5% level is given for all trials where such differences were observed. Duncan's Multiple Range Test was used for most of the trials. Treatments or varieties connected by the same letter are not considered significantly different at the 5% level of probability. The coefficient of variability (C.V.) given for a trial is a measure of the relative amount of unexplained variation present at a test location. The smaller the coefficient of variability, the less unexplained variation. A C.V. below 10% is considered very good.
The yield and performance of a variety in any one year or from a very limited number of trials may not be an accurate indication of its performance under another set of conditions. We would not recommend changing completely to a new variety with performance in a limited number of trials the only basis for selection.
Description of methods used to obtain data reported in this report:

Tasseling Data: when 90% to 100% of the fertile plants are beginning to shed pollen.

Ear Height: distance from the ground to middle of ear shank.

Bushel Weight: determined on air dry samples.

Moisture Content: Burrow Moisture Meter.

Harvest Population: based on count of consecutive plants in 1/200 of an acre.