Paul O. Johnson
Weed Science Coordinator
As corn emerges this spring, take the opportunity to check your fields to make sure that the cold spring temperatures did not have an effect on normal corn seedling emergence.
An important consideration is how even the stand is after emergence. In order to determine this, use a tape measure to observe and record the distance between individual plants at twenty feet lengths. Repeat this in 3-5 locations across each field. Next, add all the readings recorded together and divide by the number of plants observed to determine an average distance between plants in the field. The final figure should be in a range of plus or minus 2.75 inches. Each inch of variation above, will result in yield reductions of four bushels per acre.
If your variation is over 2.75 inches you are losing yield potential. For example, if you have a variation of 5.75 inches you would be looking at a yield loss of 12 bushels per acre. If the market is offering $5 per bushel for corn, this variation will result in a 60 dollar loss per acre in potential income. Using these guidelines can help to determine if there is a need to re-plant.
Source : SDSU