What is the difference between the John Deere 1E 23 and 1R 25?

Here is how the John Deere 1E 23 and John Deere 1R 25 compare on John Deere's published specifications:

• Horsepower: John Deere 1E 23 22 hp vs John Deere 1R 25 23 hp
• Fuel capacity: John Deere 1E 23 5.6 gal. vs John Deere 1R 25 5.4 gal.