here's an interest quote for you all:
Plants Don’t Use Many Nutrients
How can we grow food year after year and not run out of nutrients? An important fact is that plants don’t use a lot of nutrients.
van Helmont did an interesting experiment in 1684, where he showed that you could grow a 164 pound tree from a couple of ounces of soil.
The amount of minerals in food is very small compared to the amount in soil. But how small?
Consider this calculation. Soil contains 1-5% iron – let’s use an average of
2% which is 400,000 mg/sqft, in the plow layer. A
carrot weights 50 g and contains 0.3 mg of iron. So that 1 sq ft of soil has enough iron to grow 1.3 million carrots. That is a lot more than 50 years of farming.
Source:
https://www.gardenmyths.com/soil-fertility-decreasing/