Assessing microbial community changes in organic cropping under leguminous and non-leguminous ground covers compared to plastic mulch

This study compared traditional plastic film mulching with leguminous and non-leguminous ground covers by examining physical, chemical, and microbial soil properties. Globe artichoke was the study crop; the edaphic factors were the primary emphasis of this study. Ground covers, including leguminous and non-leguminous cover crops, have the potential to enhance soil health and microbial diversity compared to conventional practices such as plastic mulching. This study investigated the effects of leguminous (White Clover, Trifolium repens ; Crimson Clover, Trifolium incarnatum ) and non-leguminous (Buckwheat, Fagopyrum esculentum ; Kurapia, Lippia nodiflora ) ground covers in Artichoke production. Soil samples collected over two years from 20 plots in Camarillo, California, were analyzed for microbial diversity, functional activity, and nutrient cycling using methods including 16S rRNA sequencing, phospholipid fatty acid analysis (PLFA), and Biolog EcoPlates. Plastic mulch plots demonstrated high short-term fertility, with elevated organic matter and Microbially Active Carbon levels, but showed reduced microbial diversity and higher CO₂ soil respiration, indicative of carbon loss. In contrast, cover crop treatments fostered distinct microbial communities and improved soil health. White Clover treatments enriched nitrogen availability and promoted unique microbial taxa such as Adhaeribacter sp., while Kurapia enhanced arbuscular mycorrhizal biomass and phosphorus availability. Crimson Clover demonstrated balanced improvements in soil chemical properties and microbial carbon metabolism, and Buckwheat provided moderate benefits with an emphasis on organic matter retention. These findings highlight the potential of leguminous and non-leguminous ground covers to replace plastic mulch by improving soil microbial community composition and functional activity. This study underscores the importance of biologically driven soil management practices to enhance soil health and ecosystem sustainability.