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.