That was back in the 1970s, when the cheesemakers' discarded whey was used as fertilizer and pig feed.

FORBES: Making Whey

That was back in the 1970s, when cheesemakers discarded whey as fertilizer and pig feed--two of its loftier uses.

FORBES: Making Whey

The volume of cottonseed garbage during the 1800s became so problematic that a number of states passed laws to regulate its disposal.16 But while the bolls and leaves were still trash, in the early 1900s the seed began to move up the value chain to be used as fertilizer and animal feed.

NPR: Texas Cotton: 'Farmer Profits at Every Step'

Growing crops to feed animals requires a lot more land, energy and fertilizer than growing them to feed people, he says: 70% of the land that was once Amazon rain forest is dedicated to grazing.

FORBES: Technology

After their cotton had been ginned, farmers would keep some of the seed for next year's planting, plow some into the ground as fertilizer, and use the rest to feed their cows.

NPR: Texas Cotton: 'Farmer Profits at Every Step'