Today is one of the most important holidays on the calendar for citrus lovers. May 4 marks National Orange Juice Day, and there is no better duo to celebrate the fruit than Tropicana and Rickie Fowler. The two unmistakable orange icons have teamed up to prove that OJ belongs on the course and in the glass. Fans who comment on Tropicana and Fowler's shared Instagram post from National OJ Day, Monday, May 4, through National Mimosa Day, Saturday, May 16, with the name of their favorite orange cocktail or mocktail will be entered for a chance to win a once-in-a-lifetime Tropicana juiced-up beverage cart, the ultimate way to roll through your round in Rickie style.* (The full rules and regulations for the beverage cart are below the interview.) For more than 75 years, Tropicana has been part of how people start their mornings, and Tropicana Pure Premium, which is made with just one ingredient, oranges, is an excellent source of vitamin C.…