Good perspective. Thanks. For how many horses would we be growing how many acres of feed for today were there no engines, I wonder.
I don’t know. Elimination of engines would cause a huge disruption to farming alone. Farmers use something like 8% of all #2 diesel fuel in the US in most years. Just replacing tractors with draft teams would be... well, it would be nearly impossible. There’s no practical way to harvest today’s grain crops with even antique engine-driven combines, much less the old horse-drawn Holt machines from the 1880’s. With today’s grain yields, you get about 100 yards before having to empty the grain bin.
There are still guys who hitch up a team and do demonstrations of horse-powered farming. Sometimes you see them at county fairs. For people who want to get some perspective, I’d suggest seeking them out. It is highly educational. Here in the Great Basin, where the desert environment preserves things made of wood, you can still see the hay-making machinery from the horse-powered days on ranches all over central Nevada, Utah, Idaho, etc. From talking to old-timers here, the job of putting up hay was a non-stop, every day job from about July until mid-September on most ranches. Cutting was the easy part - a two horse team and a ground-driven sickle mower.
Gathering the hay up was more difficult. They used dump rakes, and a guy raking had to have good driving skills and a steady horse.
Putting the hay into a pile (baling really wasn’t done much then) was a team affair, and you needed a couple of steady horses in the team, or the buckslide was across the field and in the fencerow if the horses spooked.
The old timers have told me that the #1 issue in horse-powered haying was horses that spooked. A skittish horse could cause other horses to skitter, and horses that started boiling up on you made for headaches that took hours to untangle.
That all said, the use of modern herbicides and pesticides make horse-powered farming more possible than it was 100 years ago. Using horses for tillage was what kept farm sizes so small 100 years ago. The biggest team ever put together for tillage was (I think) 48 draft horses under one hitch, and they pulled something like 43 or 45 plow bottoms. Today, a 300HP 4WD tractor would play with that rig. Driving 48 horses, even draft horses, is a challenge even if all the horses are co-operating. Holding all the leads in your hands is practically impossible.
So, eliminate the tillage, use spraying to no-till the crops, and we’d be a lot closer to modern outputs - right up until we get to the harvesting bit. Then we’d hit the wall.