I try to diligently add organic matter to my growing spaces through of a variety of ways to avoid having to deal with the use of fertilizers.
My main approach is the liberal use of well made compost in my beds. I will add a thick layer annually as a top dressing and let that act as a nutrient source for the plants that may grow. At first, I have worked with a local composting outfit that creates really good stuff that meets my standards and imported it by the truckload to get my spaces established due to a lack of acreage to source materials from. Now, my household composting paired with my chicken coop creates a steady stream of compost for my established spaces.
I'm working on trying to figure out a mulching system for my annual beds that I like, but I am struggling to find something that I have decent success with. My perennial spaces get thick layers of arborist woodchip mixed with desirable mushroom mycelium. This is another source of nutrients while also 'conditioning' the soil to be loose and easy to dig in. Ideally I will figure out a system so I can mulch over my layer of compost to further increase the organic matter in my soils.
When I am not growing a desirable crop in these spaces, I have started experimented on growing cover crops to further capture and release nutrients for future desirable crops. Currently, I have worked with winter-kill cover crops such as brassicas to keep a root in the soil from the autumn into the winter months with good success. By springtime, I only have to hoe the few plants that somehow overwintered and I'm ready to plant. The decaying plant matter works as a mulch in its own way.