With recent rains in some areas of NJ along with surging corn prices some farmers are axiously trying to estimate their potential yields for marketing and other purposes while those who are less fortunate need to plan for the consequences of lower yields. There are numerous ways to estimate yields but some of the basics follow. First you need to get a good estimate of plant populations with ears on the stalk. Most everyone uses 30 inch rows thus 17.5 feet of row equals 1/1000th of an acre. So walking and measuring at random thru the field or sampling specific good and bad patterns in the field will give you a good estimate of plants per acre with ears. As you go you can randomly pull off ears at the different spots you sample for plant population. If you got an average of 30 (ie 30,000 plants/acre) then select 30 random ears and husk and count the number of kernals. In really good corn with well filled kernals there are about 75-80,000 kernals/ bushel, in average corn about 85-90K and in poor corn(large popcorn size kernals) about 95-105K. If for example you had a stalk population with ears of 30,000/A, and average kernal count per ear of 400 and assumed a kernal size of 85,000/bu then you would have a yield of about 141 bu/A. Remember, the more areas of the field and the more samples you take, the better the estimates. Please see the following article for more details for estimating yields: http://bulletin.ipm.illinois.edu/article.php?id=1695
What about soybeans? Its too early yet to estimate those.
Zane R. Helsel