Mulching the garden is a very common recommendation. Mulch will reduce the number of weeds and it will hold moisture in the soil but how does mulch affect the quality of soil?
There are lots of claims that mulch improves soil but have you ever seen numbers to validate them? I haven’t either. How exactly does mulch improve soil? It should add organic matter, but how much? It should increase the number of microbes, but is this really true? Unfortunately, almost nobody studies landscapes and gardens because no one will fund the work.
Luckily I was able to find one very good research paper that looked at this exact problem.