What is worse?

Too much nitrogen fertility in the soil, or too much tillage—what do you think kills the soil faster?

And in what contexts?

Sounds like two evils to me.

Here are some threads of interest:

https://permies.com/t/93093/Tilling-Sustainable

https://permies.com/t/65316

https://permies.com/t/9382/permaculture

https://permies.com/t/137078/Plants-consume-excess-nitrogen

i think the context matters. some plants are "nitrogen hogs" and can work that out, but you can't put back soil that is lost to erosion.

As I've understood it, part of the problem with too much readily available nitrogen (and phosphorus, I assume) is that it kills off the mycorrhizal fungi. If the plants can meet their nutrient requirements easily without the aid of fungi, there's no reason for them to feed part of the sugar they make to the fungi, which then starve to death.

Meanwhile, tillage breaks up the mycelial networks, introduces excess oxygen in the soil which encourages bacterial growth and thereby depleting soil organic carbon. Tillage also leads to nutrients (including nitrogen and phosphorus) leaching out of the soil faster.

I have no clue which of these things is worse, but I suspect that the combination of the two is way, way worse than either factor on its own. Both harm the mycorrhizal fungi in different ways, and a combination of dead mycorrhizal networks and increased nutrient leaching is clearly bad news for the soil and any plant growing in it.