Big Tractor Power is out in the field with a 1,500 Bu. Brent 1594 Grain Cart. The farm is using a 620 hp John Deere 9620RX tractor to pull the Brent grain cart to keep three 400 bu. 473 hp. John Deere S680 combines harvesting 12 rows of corn at a time moving through the harvest. This video spends time in the field and up in the cab of the John Deere 9620RX 4wd and S680 combine.