Corn is still being planted, but some is just emerging or already up. This is a good time to evaluate your stand and get a report card on how your planting went this spring.
Look for uniform emergence and spacing. Corn does not like competition, be it from weeds or another corn plant that is too close. First, evaluate your population. Count the number of plants in 1/1000th of an acre (23’9” for 22” rows, 17’5” for 30” rows). Do this in 6-7 different spots in your field and average that number. Your actual results should be within 5% of what you planted. We get about 5-6 bu/ac per 1,000 plants. Any reduction from this will dramatically reduce yield.
While you’re determining plant population, also check stand uniformity. Take an average spacing in each of the 6-7 locations. Ideally, 80% of the plants should be within 2 inches of the target spacing (9.5” in 22” rows, 7” in 30” rows with a stand of 30,000 plants). You should come up with a nice bell curve. Dig for the seed in those wide spaces to see if it was a germination issue or a skip. Gaps in your corn leave you with a field that is not fully utilizing moisture and sunlight throughout the growing season. This lost energy is not going into the crop and therefore not into yield for you in the fall.