Suppressive abilities of legume fodder plants against the invasive weed Parthenium hysterophorus (Asteraceae)

Abstract

Abstract The alien invasive plant Parthenium hysterophorus (Asteraceae) has been reported to impend smallholder farmers’ livelihood, and biodiversity conservation in sub-Saharan Africa. While earlier studies reported that the invasion may be supressed if plant density in invaded habitats is sufficiently maintained, only a few quantitative experiments on competition between legume (Fabaceae) fodder plants and invasive plant species have been conducted. We determined whether three selected test legume fodder species, Desmodium intortum (greenleaf desmodium), Lablab purpureus (hyacinth bean) and Medicago sativa (lucerne), can suppress P.\xa0hysterophorus growth. These legumes were selected because they have been used to suppress various weeds in sub-Saharan Africa owing to their rapid growth, strong root systems, bigger leaf canopy, high biomass production and capacity to form many branches. Also, they are used by livestock as forage when other fodders are dry and become limited. The legume fodder plant species and P.\xa0hysterophorus were grown as mono- and mixed cultures in pot experiments. Fifty-day-old P.\xa0hysterophorus seedlings were harvested to determine any suppressive abilities of the legume species against the invasive. We found that the growth of P.\xa0hysterophorus was negatively impacted when grown with two or three test legume species compared with monoculture. Respectively, stem height, total fresh biomass and leaf chlorophyll content of P.\xa0hysterophorus seedling were reduced by >60%, >59%, and >70% when grown in combination with all three legume fodder species compared with sole cropping or in mixture with just D.\xa0intortum or M.\xa0sativa. The results suggest that the selected legume fodder plants have the ability to suppress growth of P.\xa0hysterophorus. Further, this study demonstrates the potential importance of using legume fodder plant species in the management of alien invasive plants.