Zero-till farming will come to parts of the mid-west in fits and starts as farmers realize that the current methods are unsustainable, in most places there is no need to "plow it up".
In western Canada farming practices involve more crop rotations and less tillage, the net result has been increasing organic matter in many areas. I farm in an area with a surplus of organic matter, and too much can be a problem, so we still engage in a lot of tillage under normal precipitation conditions.
What kind of problems do you see with too much organic matter? I really like to garden and often find myself going overboard on mulch and compost and paradoxically seem to notice slower growth sometimes when I use them. I wonder if it is too much organic matter?
I can't speak to the exact circumstances in your garden but too much organic matter can have the effect of "tying up" nutrients in the organic matter in a way that makes them inaccessible to crops - if you grow to large a microbial biome in the organic matter they immobilise nitrogen.. I am not an expert on this so I only understand it in broad strokes.
I am a bit of gardener and my anecdotal advice is - I don't know what sense you are using the word "mulch" here so I am not sure about that but too much compost can be an issue if you are not letting it break down long enough and not incorporating into existing soils well enough. Too much compost will grow wicked-hot radishes, but your leafy greens will be ugly and taste like garbage in my experience. The thing about gardening is it is all small sample sizes.. it ain't science and it is hard to know what's up without a good old fashioned site visit!
In western Canada farming practices involve more crop rotations and less tillage, the net result has been increasing organic matter in many areas. I farm in an area with a surplus of organic matter, and too much can be a problem, so we still engage in a lot of tillage under normal precipitation conditions.
https://agriculture.canada.ca/en/agriculture-and-environment...