The adjective would apply to the word dependence. I'd like to say commodital, but Google says it isn't a word.
No, but you can use "commodity" itself as a noun adjunct: "commodity dependence". Or just rephrase with a preposition: "dependence on commodities".
Edit: I did find one use of "commodital" in a pseudo-academic context (link):
Language-centered writing involves a major alteration in textual roles: of the socially defined functions of writer and reader as the productive and consumptive poles respectively of a commodital axis.
Without more context, it is difficult to say what you are after exactly. But in a financial context the word you are after might be commoditized or commoditised in British English.
An asset which is commoditised becomes indifferentiable in terms of its value. Examples of commoditised goods are gold and crude oil.