Hemp/ Cannibis/ Marijuana are the best crops for carbon capture. Not only do they store 80%+ of the carbon in their roots, one acre of hemp will capture 10 times the amount of carbon as one acre of trees, provided the hemp is harvested at least once a year, and the roots are stored at the bottom of the ocean or something. You can harvest that acre up to 4 times a year in some parts of the world, and hemp can be used for food, fuel, clothing, rope, paper, shelter, concrete, and a ton of other stuff.