Control strategies for the invasive plant kudzu (Pueraria montana) only minimally impacts soil activity, chemistry, and bacterial and fungal communities

Invasive plant species pose serious threats to biodiversity and stability of native ecosystems. Kudzu (Pueraria montana var. lobata) is an abundant and highly aggressive invasive plant in the Southeast United States. Herbicides, bioherbicides, and cultural practices are integral parts of integrated management of kudzu, yet few studies have evaluated the impact of kudzu management strategies on soils and their biological and chemical properties. To examine whether kudzu management options impact edaphic chemistry and/or soil microbial communities, we implemented a randomized complete block design (RCBD) with kudzu control treatments, which included synthetic, biological, and combined herbicide applications as well as mowing. Changes in edaphic chemistry, soil activity, and in bacterial and fungal communities were then measured across a single growing season. Treatments included the herbicides glyphosate and aminopyralid, the fungal bioherbicide Albifimbria verrucaria, mowing, as well as the combined treatments of aminopyralid and A. verrucaria, glyphosate and mowing, and two controls (untreated control and the surfactant used as a carrier for aminopyralid and A. verrucaria spores). Soils were collected at multiple points across the growing season between May and September. Soil enzymatic activity and edaphic chemistry were generally stable across treatments and time. Further, our community analyses indicates that the interaction between treatments and time structures fungal and bacterial soil communities, but only weakly. This study suggests that soil microbial communities are generally stable in response to different management strategies and had no discernable adverse non-target effects. We conclude that land managers likely can use any control strategies that are best suited for their circumstances without undue concern about how kudzu control strategies might impact soils.