Thanks, very interesting. I know most composters / gardeners won't think applies very much, but we often see comments here to just add nitrogen to e.g. woody waste. I'm not going to say never appropriate, but often have wondered 'what's the hurry?'. For the most part, in compost you want the materials to be stable (meaning 'mostly done composting'), not necessarily thoroughly and completely degraded/decomposed. Woody/carbony waste left to its own will eventually get colonised by microbes bringing their own nitrogen.

(Not making any rules or recommendations, just musing).

Quasi-related - checked out a depression in my yard that I'd mostly filled with sawdust last year (snow finally gone). Grass has grown fine, sticking a finger down, feels and smells like soil. Softer than the soil around it, is the biggest obvious difference. It did benefit from application of a bit of, ahem, natural urea.

Compelling article. I wonder if the authors have changed or strengthened there findings since then.

I did a quick search on the net and here is another study from 2017 kind of running contrary to the older study. Optimal application of fertilizer was found to increase soil carbon. Under or over application was associated with a decrease in soil carbon.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172293

thanks to both of you for the articles. One wonders what fully natural urea does to the soil. Not only of interest for gardeners that have reverted to nature, but also fertilization by livestock involves large quantities of natural urea.

I'm going to guess there is a limit to benefits from natural urea, on a pasture for example. Same way that intensive grazing can degrade the system. Nature let the cattle roam over large areas so you would think the soil/grasses etc. have evolved to thrive in that system. I'm just spitballing.