Is corn a good cover crop

The pic doesn't show how much corn was planted be the JD combine

Planted.
What percentage of the harvest do combines leave in the field?

If it was chopped for silage with forage harvester, none.

I don't know the answer, but I've heard Gleaners referred to as Silver Sided Seeders.

We chopped a lot of corn for cows.
I haven't seen anyone in Terre Haute chop silage.
They use round bales of hay to feed cows.
I don't know anyone who milks cows either.
I wonder if corn is too valuable to make silage?
Dad chopped the corn that wasn't going to produce a good harvest.

all combines do a poor job when misadjusted. that said look at if a good operater is harvesting 200 bu corn, 2% loss is 4 BU of corn per acre. if you plant 32000 pop at planting 2 % loss is 10 times thicker!! 2 to 5 % loss is AVERAGE!!! early harvest and good rain makes it look worse because of rapid growth!! gives the appearance of poor harvester!! gives the morning house of knowledge something to talk about. my 2 cents worth. Good day!!

Your opinion is worth more than 2 cents.
Next question.
Will the corn left in the field actually yield more in Nitrogen, P or K than the cash value of the corn? If so then corn as a cover crop isn't a total loss.

The amount of green there looks excessive to me. But hard to tell in that picture. We don't have green come up in our fields from corn. Though at close to freezing in the fall during corn harvest would not get it up like that and would rot by spring.

I spent many years working with a combine harvester manufacturer in Europe, and then more years travelling around eastern England assessing grain losses on various makes of combine. As has been said, 2% to 5% is the average through the combine and many farmers, do not know what that looks like. We used a wire frame 12 inches by 12 inches placed in the swath behind the combine then counted to grains in the frame. If a farmer saw more that 10 to 12 grains he would start complaining about losing grain but, on average, that number of grains worked out at about 1/4%. We had a series of boards with grains stuck on them to demonstrate what a grain loss of 2% looked like and most farmers were horrified.

The greatest area of combine loss was from dropped heads at the cutter bar and shelled out grain from the reel. Another area was from trying to get too clean a sample and overloading the returns system leading to a trail of grain from either the sieve pan or the straw walkers depending where the returns were fed back into the machine.

With the advent of straw choppers and spreaders most people do not check grain loss even though they have monitors. Monitors are only as good as the operator who adjusts them. I met many operators who believed that, if he adjusted the monitor to show no grain loss, he was doing a good job no matter how much was going over the back.

Pic isn't great. Looks like an excessive amount of green if you were there.
Corn planted 2 weeks before frost date. Early harvest.

i don't know the value but has to be SOME!! Think about this, giant foxtail would make about as good of covercrop as rye, mother nature makes go to seed to much!!

The corn stubble closest to the grass looks like it has ear drop. The ears might have been on the ground before the combine came through. Cant tell what happened in the stubble farther out. Could have been shelling in the head or loss out the back of the rotor or sieve loss. If it came out of the rotors the straw chopper will spread it out. If it came over the sieves the corn loss will be concentrated in a narrower strip behind the combine unless the combine has a chaff spreader. The volunteer corn does look excessive but its hard to tell what was going on.

I dont leave corn out the back of the combine because i check on the ground quite often .the corn we leave is from the corn head from butt shelling on small ears

Some corn varieties have issues with header loss. A neighbor had that problem a few years ago. The ear butt shells to some degree. If unusually dry going into harvest can affect ear loss. Some varieties need to be harvested at a fairly moist level (into the 20's) to minimize header shelling. Could be an inexperienced operator. Maybe something broke with the combine. Just about any combine will do a very good job with a good operator along with being properly serviced and adjusted.

Some corn varieties have issues with header loss.
I think you are right. If the corn came out the back you would see concentrated areas of corn growing. It looks like the corn is planted evenly.
Header loss is a good explanation.

As someone that is being educated by your discussion; I was wondering what 2 to 5 percent loss really means.
So I looked up a few things.

200 bushel per acre corn at 3.5% loss would be 7 bushels per acre.
Corn has 75,000 to 90,000 kernels per bushel so lets use 82,500.

So you guys are saying a combine in working order is planting 82,500 x 7 = 577,500 kernels of corn per acre.
Seems the combine does a better job of planting corn than the planter does.

And 7 bushels per acre x 1000 acres is a loss of 7000 bushels.
At $5 a bushel thats $35,000
Seems it would pay to have a dealer go threw a combine every year to repair or tune-up the combine.

A bushel to two is a good goal for loss...2% in corn is quite a bit.

Back when farmerss had livestock that grew corn it was no big deal just turn in the hogs,geese,chickens etc.Or lease your land for dove hunting.

A landlord who goose hunts always grumbles I don't leave enough for good hunting... I usually pull some off his farm as silage so it's some of the first open ground around.

turkeys and deer take everything I lose in the field, and probably 10% before I get there. Also beavers take their toll also. significant, but I only have ten acres for feed, hopefully for cows.

John, 7 bushels is a lot. There isn't just one reason why corn might be on the ground after the combine passes through. after all the years and thousands of hours I have been operating and working on combines I am still amazed at how all of that material can go into the front of a combine and be sorted out and separated in just a few seconds. Corn and soybeans, in fact all large grains are easy to separate, It's when we get into the heavy yielding small grains where I just can't get over the miracle that happens inside that machine.

With corn if the ear doesn't shell real easy and the stripper plates are set at the proper distance apart you should see almost no kernals on the ground behind the corn head and only a few broken kernals behind the combine. The corn head pulls the stalk down between the stripper plates very violently, so fast usually the human eye can't see it go down. When the stalk is on the way down the ear hits the stripper plates and being too big to big to make it through the strippers the ear is pulled off the stalk violently again. This might shell some kernals off the butt of the ear. Some of those kernals end up in the combine but some of the kernals go on down to the ground. The corn plants can vary in size and strength across the field. If there is a sandy place in the field the stalks and ears might be smaller in that sand. The ears might go right on down between the stripper plates and end up being ground up in the stalk rolls and sprayed down on the ground. This is why we see more volunteer corn in some areas of the field and no volunteer corn in other areas. If the corn has been blown over by the wind we will see tons of volunteer corn from plants the corn head cannot pick up. Those clumps of volunteer corn in George's picture might be from stalks knocked over by animals at the edge of the field or the corn might have been down in that area or the ear might have dropped off the stalk before the combine went through. The reason we see the volunteer corn growing in this picture is because the stalks were disked and the kernals incorporated into the soil. If the stalks are left alone in the fall we won't see volunteer corn until spring.

Obviously waste is a factor to try to lower as much as possible. However, modern machinery makes it possible for 1 person to harvest many acres. Imagine the no waste method of picking all by hand. Not that long ago in a place not far far away. Machines are just amazing things and hats off to those who invented and improved them.