Corn Establishment and Development during 2004

Joe Lauer , Corn Agronomist

The 2004 growing season has presented numerous problems so far, especially for farmers in eastern Wisconsin . Frequent rain showers have prevented farmers from planting corn as well as soybean. Many farmers are looking at an "emergency" forage situation.

Numerous production fields have yellowing. With exception of field low spots, plant survival and stand is good. Army worm seem to be more of a problem this year. Corn development at sites where the public hybrid trials are established is normal, except for Fond du Lac where frequent flooding has caused yellowing and slower growth.

Figures 1A and 1B summarize precipitation and daily temperatures for the Arlington Agricultural Research Station during 2004. As of June 22, precipitation for 2004 is 4 inches above the 30-yr average for Arlington . Significant precipitation occurred around May 21 while much of the soil surface was bare.

Temperatures were average to above average during April, but have been below average since. Only 7 days have been above 80 degrees so far. The last significant low temperature occurred on May 3 when the minimum air temperature was 22 degrees. I was concerned about frost damage to some plots we had planted on April 12 and the public hybrid evaluation trial planted on April 24, but both trials had not yet emerged and no detrimental effects have been observed so far.

Growing degree unit (GDU) accumulation was near average until May 20 (Figure 1C). Since then all April and May planting dates are below average in GDU accumulation and plant development is behind. June planting dates are accumulating GDUs in an average fashion and development is average.

There is a lot of growing season to go yet, but in general corn is looking average, except for wash-out and ponded areas. Lay-by will be occurring for April planting dates in the next week.

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