Organic mulches such as grass clippings add beneficial microorganisms to soil as they decompose

https://smb.selmatimesjournal.com/article/Landscape-Supply-House-Grand-Opening-Lubbocks-New-Destination-for-Landscape-Professionals?storyId=67cafe02bb465f0008aa0d59

Organic mulches such as grass clippings add beneficial microorganisms to soil as they decompose, improving soil structure and fertility over time.