Most people don't have Alkaline soil. That's why you put lime on fields, because it is too acidic.
We don't use Iron Sulfate as a fertilizer because it is absorbed by the plants and in things like corn the increase in Iron can make the things raised in the soil poisonous to Children and pets.
This isn't "new". And and it isn't patentable because it is a chemical that has been used for fertilizer in Kale and Spinach for 100+ years.