So basically: this is nice, but there's no reason yet to think that this could be the way we slurp carbon out of the atmosphere and avert climate catastrophe. Right? Drat.
So, no carbon scrubbing while feeding the world, but you could maybe scrub carbon by taking massive amounts of excess crops and burying/sealing them away. Not sure what the cost/efficiency of that would be.
As far as I know, the majority of net oxygen production happens through algae, because they die and sink to the bottom of the ocean, permanently removing carbon from the carbon cycle.