One of my favorite topics, used to teach it in the fall.  We would take the seniors to a local field and calculate the loss we found to the farmer, recommend some changes after discussing it in class and grade the students on their performance.

Did the same thing as a county agent, do the same thing when I am riding combines or walking fields now.

Remember, the bigger the combine, the bigger and faster you can make the mistakes!

4 beans per square foot is a bushel loss and we are finding 8-10 this week, got variety shatter problems even when the stem is green!

At 3000 seeds per lb you have 180k in a bushel for comparison to corn which is 80-90k per bushel so only two kernals or so per square foot is a bushel loss.

We have a lot of diplodia, anthracnose, giberrella etc this year so ear loss is a problem.  Only a 3/4 lb ear per 1/100th of an acre is a bushel loss and many fields have that before the combine goes through!  That is called pre-harvest loss for those who don't know(sorry, teacher in me).

http://www.google.com/search?q=combine+harvest+loss&hl=en&lr=&rls=GGLR,GGLR:2006-04,GGLR:en&start=10&sa=N

The Iowa State link at the top is a good one, the one from Univ Ga has some good worksheets you can print out, there is a good Canadian link etc.  Dr. Delbert Byg at Ohio State best this into our heads 35 years ago and it has been a great help to us.

Pretty silly to raise a good crop then scatter it all over the ground at harvest.  Another challenge is raising a harvestable crop and sure hear a lot of horror stories on here every year!

My main complaint is spreading residue evenly past the ends of these wide heads.  Very few are doing a good job.  Yet if the custom app or hired hand banded their fertilizer like that they would be  up in arms!

Ed