Current plant density recommendations for corn grain production are 26,000 to 30,000 harvested plants/A.
Current recommendations for corn silage are 2,000 to 3,000 plants/A greater than the density planted for grain.
Compared to 30-inch rows, plant density of corn grown in row widths 36- to 38-inches should be decreased 2,000 plants/A. Plant density of corn grown in row widths 15- to 20-inches should be increased 2,000 plants/A.
Optimum plant density of current hybrids appears to be greater than current recommendations.
Response to plant density is likely field and hybrid specific.
Suggest and encourage trying slightly higher plant densities on your farm in the range of 30,000 to 34,000 plants/A.

Corn forage yield and quality response to plant density at Arlington . Each point is the treatment mean of 3 to 4 replications.

Plant Densities for Corn Grain and Silage: An Update