Rapid Growth Stage in Corn

Early corn planting dates often occur when soils are cool, night time temperatures are low and heat unit accumulation comes at a very slow pace. The first 3 to 6 weeks of a corn plant’s life can be a slow struggle with seemingly little progress but around V-4 permanent roots are becoming established and with increasing temperatures the rapid vegetative growth stage of the crop is quickly approaching.

Corn growth and physiology research performed by Purdue shows some impressive statistics about the crop’s growth potential from V-4 stage through tassel or 21 days after planting to 71 days after planting.

1. Root length increased from 54 miles per acre to 32,000 miles per acre
2. Above ground dry matter weight of the stover increased from 29 pounds per acre to over 9,000 pounds per acre.
3. 73% of the seasonal nitrogen uptake enters the plant along with 74% of the phosphorous and 85% of the potassium.

While most of the dry matter weight added during this 50 day period is comprised of carbon, hydrogen and oxygen supplied by the air and water plant growth cannot continue without adequate supplies of essential plant nutrients.  It is important to maintain proper agronomic nutrient levels and monitor these levels with the use of a good soil testing program so the soil will be able to supply the needs of the crop through this rapid nutrient uptake phase.

A good scouting program prior to tassel may reveal visual symptoms of nutrient deficiencies if soils were unable to meet the high nutrient demands during this short window of time and data provided through plant tissue testing will help reveal critical nutrients that may be in short supply.

Data from University of Illinois

Information provided by the University of Illinois suggests that the crop must successfully build a “photosynthetic factory” comprised of approximately 5 tons of dry matter per acre to be well positioned for maximum production that will follow in the reproductive stages of growth.