Do you have a source for "poisonous"? The studies I've seen indicate that some grain crops may lose a bit of nutrient density (zinc, iron decreasing by 5-14%)

Do you have a source for "poisonous"? The studies I've seen indicate that some grain crops may lose a bit of nutrient density (zinc, iron decreasing by 5-14%) while other crops are unaffected or may increase in nutrition. e.g., overview at https://www.scientificamerican.com/article/swelling-co2-cuts-nutrition-in-food/ https://www.scientificamerican.com/article/swelling-co2-cuts...