I bought a Goumi 'Sweet Scarlet' and it's supposed to be a nitrogen fixer so I'm wondering what I could plant with it that might benefit.

If I plant another fruiting shrub next to it, would the root competition cancel out any benefits from the extra nitrogen?

In general, my area has poor soil and I've found plenty of lists of plants that thrive in those conditions. I bought the goumi for the fruit, not to fix my soil. I just wanted to take advantage of the extra benefit. I was looking for something like a list of plants that require higher nitrogen but haven't found anything yet. Or maybe it's not worth the extra effort?