CO2, Tempature, and N

I was looking for some sort of guidance regarding Co2 injection into my growing environment when I found this research paper. It seems, unless I am reading this wrong, that increased CO2 alone doesn't help the plant (wheat in this case) unless the nitrogen levels and temperature are ideal enough to allow the plant to efficiently use the Co2. Furthermore, it seems that after the initial growth period increased nitrogen may not provide any growth or fruit benefit. Perhaps, a good thing to use in the first few weeks from seedling to small plant and then same the few dollars and back off. I have seen a few sites where folks make their own Co2 system, and the CO2 bucket system. Maybe after I get a grower built I will look into that.