Tracking Corn Growth and Development: May 3 Planting Date Emerged
May 21, 2003 10(10):79-80
Joe Lauer, Corn Agronomist
Corn planted on May 3 has approximately 50% of the coleoptiles emerged from the
soil. With the cool weather experienced from May 3 to May 13, GDU accumulation lagged
and so both the April 15 and May 3 planting dates are behind in development from
the 40-year average. The model predicted emergence of the May 3 planting date well
(Figure 1). The planting date emerged after 130 GDUs (the model predicts 125 GDUs
are required for emergence), but GDU accumulation for 2003 is nearly 30 GDUs behind
average for May 3 planting dates.
The April 15 planting date is at V2, the May 3 planting date is emerged (VE) and
the May 13 planting date has not yet emerged. For the April 15 planting date the
plants do not have a very green color yet. Plants are entirely dependent upon the
radical and seminal root system. Nodal roots are just beginning to form. Often I
see short-term nutrient deficiency problems around the V3 stage until the dominant
nodal roots have taken over nutrient uptake.
The May 3 planting date is pretty yellow coming out of the ground. This planting
date is also more uneven than the April 15 planting date. A few plants have one
fully emerged leaf, some plants have rolled leaves nearly 2 inches long, and most
plants only have the coleoptile tip emerged from the soil.