All things in moderation. The use of fertilizer does increase production but once you start you have to keep it up.
Growing tobacco without heavy fertilzation is unprofitable.
Hay production also mines the soil and evetually you must fertilze, hopefully with the aid of a soil test.
I grow some vegetables commercially to sell at a local produce auction. I can plow sod and not fertilize the first year. Need some fertilizer the second year. Find it best to plow more sod for the third year.
I have pastures that have never been fertilized in 35 years or more that remain productive in improved grasses and clover. They do tend to have the benefit of brought in hay and grain fed to livestock.
I run a low input operation, no hired help and a minimum of purchased items. There are things you need to spend on but:
I have found striving for maximum production creates a self perpetuating cycle that is not as profitable for me or my farm in the long run.
I like cows that are fertile, milk good and do not eat me out of house and home. I have Red Polls now but over the years have had a lot of dairy influenced black and BWF cows. My cattle have a good reputation at our local stockyards even though I've never worried about epds all that much.
The farm is in better tilth and production than it was over 30 years ago when I bought it. Feeding cows on bare and thin ground has worked good for me, impoving the land without much use of fertilizer.