This actually points to something I've talked about at length before -- People see that something is made of plants and assume it's green, but industrial processes use a lot of energy at every step, so just because you ultimately use a plant doesn't mean it's necessarily green.

One very important thing that fossil fuels are used for is the production of fertilizer. Ammonium Nitrate fertilizer is produced using 2% of the world's natural gas, and that same fertilizer is presently becoming too expensive to bother with, which is one of the things that are going to lead to the incoming fuel shortages. In 2009 I did a study with publicly available data that suggested that we would have to use 1/3 of ALL non carbon fuel sources on earth to make up the ammonia production that year. I don't believe that has changed substantially enough for that to be a solution.

https://lotide.fbxl.net/posts/6006

For transportation and running their tractors, I think there might be options. Farmers could get their own oil presses and extract oil from their own seeds, then turn a bunch of that seed oil into diesel. Of course, that would only benefit the farmers who grew enough seeds to extract enough oil to be self-sufficient with regard to their diesel.

The reality is that politicians and businessmen have been lying to you, which is why you don't realize how much we rely on fossil fuels. Once you start digging, all sorts of things that they call "green" are in fact soaked in fossil fuels. It isn't clear at all how we can change all the stuff we need to change and to do it sustainably because fossil fuels are incredibly useful.