Ecological Invasion, Impact, and Management of Johnsongrass [Sorghum halepense (L.) Pers.] for Sustainable Livestock Production: A Systematic Review

Abstract

Sorghum halepense is widely recognised as one of the most aggressive invasive perennial grasses affecting agricultural ecosystems worldwide. This systematic review synthesises existing scientific evidence on the ecological invasion dynamics, origin, distribution patterns, impacts on both biodiversity and livestock, and management strategies. A systematic literature review approach was employed to identify and evaluate peer-reviewed and grey literature. Relevant studies were retrieved from major scientific databases, including Google Scholar, PubMed, and ResearchGate, using predefined search terms related to S. halepense, invasion, impact on native plants and livestock, and possible control measures. Articles were screened based on relevance, methodological quality, and thematic alignment with the objectives of the review. The results showed that Johnsongrass is making a gradual invasion in South Africa through seed production and rhizome systems. Sorghum halepense alters native species composition, subsequently reduces biodiversity, and outcompetes native species. Although it may provide forage under certain conditions, its accumulation of cyanogenic compounds and nitrates poses serious poisoning risks to herbivores. Management strategies such as mechanical, burning, and chemical methods vary in terms of effectiveness. Some of these measures are influenced by the genetic make-up of the plant, costs associated with each control measure and other environmental factors. This review highlights the need for integrated management approaches that balance invasive weed control with sustainable forage production. This review emphasises the importance of adopting integrated management strategies that effectively control both seed production and underground stems. Future research should prioritise climate-responsive management approaches, improved understanding of invasion ecology, and the development of cost-effective control measures. Bringing together policy makers and specialists in weed science, natural conservation science, and animal health will be essential for reaching consensus on the actions required to curb the expansion and reduce the economic losses associated with the abundance of Sorghum halepense in our ecosystems.