Still cotton pickin'; UPDATED with photos of night harvest

Mr. Cotton Farmer started to harvest his cotton on October 9th. That was over two weeks ago. With the exception of one rainy day, he's been picking every single day, sun up to past sun down, and he's still not done.

Still pickin' (way out there)

A fuel tank in the field

Fuel tanks are on the roads, too, hauled by large pickups. They do not travel fast.

My in-depth research (!) for this post revealed that fuel tanks come in a variety of sizes: 300, 500, 750, and 1000 gallons. I also learned that tractor fuel "economy" is not measured in miles per gallon, but in horsepower hours per gallon (hp hrs/gal). If I understand this correctly, the issue isn't how far can it go, but how long it can run. 

Let's assume Mr. Cotton Farmer's tank holds 500 gallons, and his tractor gets 18 hp hrs/gal.* His tank holds 27 hours' worth of fuel. His tractor runs more or less continuously from 8am until 7pm. He needs to refill his tank every third day. He's been picking for 17 days. That would be six fill-ups so far. (It has to be filled up on 10/9.)

Mr. Cotton Farmer does not get a break at the pump-- he fills up just like the rest of us. Diesel is going for about $3.70/gal.

500 x 3 x $3.7 = $5550.

That ain't cheap. And that doesn't include fuel used by his other machines, including those that take the bales to the gin, or his pickup. Nor does it include the fuel he burns to plant the cotton in the first place. Or the fuel that powers the crop duster he uses to defoliate. Et cetera. 

~~

It would be interesting to look at Mr. Cotton Farmer's books. I wonder if I am anywhere close to being right.

*There are a lot of things going on (i.e., factors) with large machinery fuel economy that I need to learn. One thing is certain, this calculation is simplistic. But on the other hand, I was reading a book my son-in-law sent me. It has been suggested that simplicity in complex calculations is a good thing.The key feature of my calculation is that it doesn't have to be 100% +/- something or other. It just has to be in the ballpark.

UPDATE:

It is pitch black dark. He's still out there. I think I see a flashlight moving around. 

(I need photo instruction.)

Taken with zoom completely zoomed out

Taken with zoom completely zoomed in

Same. Tripod recommended. Oh well.

Same, but trying to get more  of the activity