Unless you do a NOL carry forward, where do you deduct the IRA contribution, if you have no income? Earned income from a W2 and Capital Losses DO NOT net, I am sure you know this.
How are you set up, as a retail trader or paid on a 1099 or K1 at a prop firm? You were not clear, do you have W2 income from a "job" as well?
You really need to ask a CPA your question, instead of counting on a correct guess on a message board, or speak to an IRS representative and get a real answer!