I drove a tractor during Summers of my youth. I drove for the biggest rice and bean farmer in the Bootheel and he INSISTED on making straight rows. At the time I worked for him he owned 32,500 acres of prime Missouri farm land and the fields we worked were so big that the tractor would almost disappear from sight.
I was taught to drive a straight row by using the hood ornament on the front of the tractor, which in my case was a John Deere 4630 with duals, a cab / air conditioner. I would sight an object at the far end of the field like a tree. Then I would find an object half-way down the field like a prominent dirt clod or chunck that was in line with the tree and the hood ornament. Once I reached my clod or chunk I was half-way there, I would find another prominent dirt clod or chuck and line up with my tree. Do this for 10 or 12 hours every day from the end of May till the Fourth of July and that was my job. I prided myself in my straight rows like any farmer in Missouri would. Have you ever driven from Poplar Bluff to Sikeston on highway 60. You drove through the country I farmed. The rows there in the soy bean fields are (or should be) straight as a string.
And now I hear they have GPS guided tractors that are hands off. That takes the fun out of it. I drove in the 70's, things have changed. I can understand where GPS guided tractors would be more efficient with less over lap of chemicals, etc. Farming was expensive in the 70's so I can imagine having to use every advantage available.