There's a lot of farm equipment with long running hours and very short windows of operation which just isn't going electric any time soon.
Yeah, a combine harvester is like a million EUR and it only operates for a few weeks each year, but then often times 12-16 hours a day. And you cannot wait for it to charge up, if the weather allows it, you need to work, not wait for the equipment to charge. I don't think these are the problematic machines, even if agriculture is emitting more than road transportation.
The main issues for agriculture is N2O (fertilizer related) and methane (manure) emissions. I think there was a study that methane emissions can be reduced by a lot by adding a little bit of algae to the food of the animals. And fertilizer and land related CO2 can be replaced by industrial processes (or biological processes in enclosed controlled environments). Is it a lot of work? Yes, but it's probably much less than completely replacing a billion and a half cars.
I don't think zero emissions should be the goal, the goal is to reduce emissions quickly, as much as possible without completely bankrupting everyone in the process. Now instead everyone is fixated on road transport, which is very-very expensive for the individuals to get to zero, and it's only responsible for 10-12% of global emissions.