Comment by reason-mr

If you repeatedly harvest crops from soil without working on building it, this is what happens. Each crop progressively removes some nutrients from the soil with the result that the soil nutrients, and nutrients in the derived food gradually decay. Most petroleum/chemically derived fertilizers do not replace such. It is a known phenomena organic farming circles. Organizations like Rodale institute are working to correct this my improving soil health - but in general we’re been on a long program of “withdrawing money from the bank account without paying in”.