Preheat the oven to 350°F/180°C.
In a microwave-safe container, microwave the orange juice for 30 seconds. Add the cranberries and allow them to soak for 20 minutes.
Meanwhile, place the pecans on a baking sheet and toast for 7 - 8 minutes. Cool and chop the pecans coarsely. Set aside.
Rinse both the wild and brown rice in cold water. Drain well.
In a 5-qt. cast iron Dutch oven, melt the butter over medium heat. Add the celery and onion and sauté for 2 - 3 minutes.
Add both varieties of rice, thyme, pepper, salt and stock. Bring the mixture to a simmer, stirring several times.
Reduce the heat to low, cover and cook until tender, 45 - 55 minutes. The grains of rice will open slightly and most of the liquid will be absorbed.
Carefully drain the remaining liquid from the pan.
Return the pan to the burner. Over low heat, cook the rice, uncovered, for an additional 5 minutes, stirring gently.
Just before serving, fluff the rice with a fork. Stir in the cranberries, nuts and parsley. Serve hot, warm or at room temperature.