How Do Permaculture Farms Handle Mineral Depletion if Produce Is Sold Off?

Hi everyone! I’m quite new to the concept of permaculture and have been reading up on its principles with great interest. One question that keeps popping up in my mind is about nutrient cycles on a permaculture farm — especially when fruits or vegetables are harvested and sold off the farm.

If the produce (which contains minerals) is being exported regularly for sale, wouldn’t that gradually lead to mineral depletion in the soil over time, unless those minerals are somehow brought back in? I do understand that nitrogen can be fixed from the atmosphere through certain bacteria and legumes, but most other essential minerals — like potassium, phosphorus, magnesium, etc. — aren’t atmospheric and would need to come from somewhere, right?

For those of you who are running a permaculture setup over a longer period, do you find the need to periodically add any form of natural or organic fertilizers to maintain nutrient balance? Or are there techniques you use that keep the mineral cycle closed even with produce being sold?

Also, this brings me to a broader question: Is permaculture primarily meant to be a self-sustaining system for personal use, or have some of you been able to turn it into a small-scale commercial setup for side income — without compromising its core principles?

Looking forward to learning from your experiences and insights! 😊