Why don’t they have a baler at the back where the straw comes out?

Possibly because they’re too busy doing everything else that would take scores of people to do in the same time?

I’ll ask those who know today for you. The Claas Lexicon something or other on the estate here has thus far munched its way through nearly 3,500 acres in the last 4 weeks where the weather hasn’t been too friendly for correct moisture content.

Combine engines won’t have enough power for a large baler, even a 500 hp combine. A combine engine is on top of the machine and drives the combine indirectly via hydrostatic drive to move the machine and a multitude of belts and pullys for the threshing mechanism. It has been done by putting an engine on the baler but not often.

Ooh arr!!!

This photo makes me smile

Primarily Time.

Farmers have a relatively narrow window of time to harvest a valuable crop / commodity whilst it is is in optimum quality condition and quality, particularly before the weather changes and ruins the crop or reduces its value. And usually there’s a lot of it to get in in a short time window

Straw is a much less valuable commodity, even considered a waste product in some cases, so the straw can wait.

😀

Pretty much as @curzon & @itstig say. The value is in the grain not the straw so the harvesters are optimised for that. Most balers work off a shaft drive from the engine so you’d have to route that power through the harvester and out to the baler unless the baler had a dedicated engine.

There’s also a lot going on for the harvester operator to be handling without having to think about the baler as well. If the baler jams or runs out of twine then that stops the harvester.

Straw doesn’t have much value, its main use on farms is for animal bedding.

All of the above. Plus

manoeuvring at headlands is hard enough without a baler on the back.

Most combines have to tow the header )the wide bit at the front) when driving from field to field, so you would need another tractor to get the baler there anyway.

when baling straw the bale count is very high so a bale will drop out every few tens of metres, that would make turning around at headlands very difficult as there would always be bales in the way.

Most tractors would be involved in carting grain to get it home ASAP so there most likely wouldn’t be a spare on left to do the baling anyway.

A combine drive real slow, the baler can be driven really fast. A bale made slowly can become extremely dense and heavy which will place undue wear and tear on the kit….

Etc.

Straw doesn’t have much value, its main use on farms is for animal bedding.

Interestingly, see it also used a lot around here to insulate / defer a crop of carrots — looks like they grow to near maturity, then they dump / scatter straw over the carrots (maybe with the leaves intact) and it seems to hold them in the ground for a bit longer, or insulate them for a longer winter crop.

When the straw is ejected it requires time to dry and lose moisture before it can be bailed to prevent the nails from rotting. That’s my guess anyway.

Thanks guys, some interesting bits there.
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What I was thinking, rather than a combine towing a baler, and it appears there are several good reasons why this isn’t a good idea) is that it should be built in at the back. Yes it would need more power and would become a much bigger machine but is that really an issue here:
Might be less practical in smaller UK fields/roads to fields

Fields by me recently got cut, the bales were massive, as big as a car.

Extra weight, more to package into an already large machine, grains can/will be put through a drying process, wet straw can’t, will/could mould, build up heat and combust!!!! Stopping for replacing string, wrapping if wrapped all slows down the machine most of which are contractors nowadays.
I used to work on the old machines when bags were used to collect the grains😁 Drop the bag off, collect the bag, store the bag then go bale the straw when it was dry enough, usually wet/damp at ground level

You’d be adding a lot of complexity and cost to an already complex machine for no real benefit. I’ve not been near one of the large square balers but the old traditional small balers rock both the tractor and baler back and forth with the power of the ram that compresses the material so goodness knows what the ram in that baler in the shot at the top of the thread does. You can’t use a baler that makes round bales as these are a clam design that has to stop and open up when the baler is “full”, i.e. it’s not a continuous process.

As @welshfarmer says, baling at the same time means the field is then covered in obstacles unless you’ve got another set of contractors shifting them, in which case you’d have a contractor doing the baling anyway.

Balers aren’t cheap machines either – 30 years ago my dad bought a New Holland small square baler. It cost £8000 which was about the same price as a decent family car. Just looking online at prices, a similar model 12 years old is for sale for £7500.

‘Straw doesn’t have much value, its main use on farms is for animal bedding’.

Or burning

Or dumping off the trailer onto the verge * before it gets to the power station.

* Roads around Littleport/Ely/Sutton area!!

Love this place.

I watched a pea harvester once. Cool, especially when it dumped the load into a trailer for the cannonball run to the place where they freeze them.

The straw is often mulched and spread on the field – not even baled.

I love some of the tech in modern agriculture – but the prices are extraordinary! A tractor costing more than most people’s houses…

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