Giant watering machines, extremely weird "collector" thingies, and a whole slew of farmers complaining to John Deere about "right to repair".
Modern Farming is about having huge infrastructure so that very few people can create lots and lots of food. Between the fertilizer, the bountiful land, the water, the sophisticated machines, etc. etc.
Also, I had a few teachers who went to the local agriculture university and talked to me about soil types and soil tests. Farmers have to be extremely up-to-date on chemistry, botany and even general biology: you survey your fields by taking chemical tests to determine the nutrients in the soil. You keep careful eyes on your crops at each stage of development: ensuring that they're progressing as expected.
Finally, you also need to be on the lookout for insects and/or animals, who can destroy your crops. But not just insects and animals... but also fungus, bacteria, and viruses. (Plants get sick too, just like humans).
If a plant-virus starts to spread in your farm, you could lose the entire crop. You're pretty much the "Crop Doctor", and need to be able to tell the different kinds of diseases that can come up (is it a fungus? Should you spray fungicides all over your plants? Should you spray insecticides? Should you burn your crops to prevent the spread?)
And despite the miracles of modern nitrogen-based farming... micronutrients in the soil still matter. So you still got that whole crop-rotation thing if you want your soil to rejuvenate between crops.
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Soil alone is already a major issue. If you've got too much clay in your soil, you need to find sand and/or compost and mix it into your land. Or you know... sell your land and find better soil.
/not actually a Farmer, but had the pleasure of talking to some...