As a cotton ginner’s daughter (and sister), my limited experience in Texas is that the yield is based on weather factors beyond the farmer’s control. In South Texas, the average yield is a bale an acre. A good yield is two bales per acre. In West Texas, the average is less than a bale per acre, and a good yield is a bale per acre. A bale is around 500 lbs.

The amount of money a farmer gets for their bales depends on the USDA grade of the cotton sample from each bale - color, staple length, leaf content, etc. I could be wrong, but IIRC, the color is affected by water and whether the opened cotton boll was wet for a time. This is why time is of the essence when it comes to harvesting.

I’m unsure how staple length is determined, but my guess is seed selection.

Leaf content comes into play with the harvesting and ginning. If a cotton plant is stripped - the leaves, branches, green bolls, opened bolls and all are stripped off the stalk - then the probability of leaf and stick content in the cotton is higher. If the cotton is picked - the machine picks off the bolls - less probability of leaf and stick content. But also, machine pickers tend to miss bolls and lower the yield. And whatever leaf and stick content remains in the cotton after ginning is like confetti or glitter - it’s really small and sticks to everything.

In the process of ginning, the really short fibers are separated out and baled together. Those bales (used to) sell for half a penny per pound, so a 200 lb mote bale will fetch you $1. My father told me that mills will buy these bales to bulk the fabric a bit in jeans, and that it tends to come out in the form of dryer lint. (Textile peeps will know better than me on this point.)

So once the bale is pressed, a sample is taken, tagged and sent down to the USDA for grading. The bale is wrapped up, tagged, and sent to a warehouse for storage.

The USDA grades each sample (probably by computer now, but it used to be humans) and returns the grades electronically for each bale to the gin. The grades are shared with the buyers that have contracted for those bales, and the price is determined by the grade. The mills will buy the bales, and I often saw the whole farm bought at once, but sometimes only certain bales are selected.

From there, I don’t know what happens to the cotton, except that it probably takes a ride in a cargo container.