Yup, as been mentioned it's way too high. They're pretty stiff sidewalls so you can get away with the lower psi. I think I only use around 6 or 8 psi in my Landmaster and seem to be wearing ok.
Be aware tho that most tire manufacturers state the max weight when stating the air pressure. For example, in a car you have passengers in all the seats and a full trunk. Most people don't drive year round like that. Unless I'm doing heavy work I rarely have the max pressure even in my tractors.
The low profile tires on cars are a bit more finicky tho, just have to experiment.