This is it. Supplimenting nitrogen, phosphorus, and potash means we can grow far more macronutrients to feed far more people than before. Letting fields follow, growing no food for years, lets the soil recover all the micronutrients mentioned in the article, but at the cost of reduced calories (Proteins, Carbohydrates, and Fats) produced per agricultural acre. And those are the things that feed hungry people. Doing more grazing and better fertilizers can help around the edges, as would simply fortifying foods directly. Thats how we cured rickets, after all.