Introduction to the XXV International Grassland Congress virtual special issue

The XXV International Grassland Congress was held in Covington, Kentucky, USA, May 14–19, 2023. The theme of the conference was Grassland for Soil, Animal, and Human Health. More than 400 presentations were delivered to an estimated audience of 650 delegates from more than 50 countries. Here, we outline the general themes presented, as well as a few specific details from some presentations that were invited plenary and keynote speeches. In addition, a select few presentations have now been published in a virtual special issue of Grassland Research—https://onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)2770-1743.xxv-igc-vi. Grasslands are essential to ruminant livestock, biodiversity, and a wide range of ecosystem services. This conference brought together scientists, professionals, policymakers, and citizens to share knowledge for making well-educated decisions now and into the future. Our collective health depends on a healthy environment, and it was the aim of the International Grassland Congress that scientific inquiry would translate into better human, livestock, ecological, and soil health conditions well into the future. The first International Grassland Congress was held in Leipzig, Germany in 1927, a gathering of 16 scientists from six European countries seeking ways to improve grassland agriculture. With this humble beginning, interest in the science of grassland agriculture has grown. The International Grassland Congress now has become the ultimate destination for those interested in the science and ecology of grassland agriculture, policy issues, sociological impacts, and much more. Digital technology has brought the diversity of interested parties closer, and yet, the International Grassland Congress continues to provide a unique forum for face-to-face connections, serendipitous interactions, and intentional networking. Participants of past congresses have learned in depth about research issues, developed collaborations, and shared best-practice strategies. Our common cause of improving life on Earth has been and continues to be strengthened through these interactions. "Grassland Ecology" covered aspects of food production, watersheds and water quality, biodiversity, carbon sequestration, greenhouse gas emissions, soil health, and climate change. "Grassland Production and Utilization" explored topics such as genetic resources, botanical composition, forage management strategies, high-intensity grasslands, seed production systems, forage nutritive value, and production economics. "Livestock Production Systems" focused on ruminant nutrition, grazing management, small-holder dairy systems, integrated crop–livestock systems, silvopastures, small ruminants, equine, and animal health and genetics. "Grassland Sustainability, Innovations and Initiatives" delved into regenerative agriculture, emerging education, technology transfer, green energy, economic drivers, participatory approaches, ecotourism, digital technologies, training enthusiasts, and planning for the future. "Grassland Policies, Social Issues, and Ecosystem Services" expanded into indigenous knowledge, governance, social justice, marketing infrastructure, policy, politics, youth engagement, perceptions, human nutrition, and niche marketing. Three internationally recognized plenary speakers reviewed the foundations of grassland agriculture and offered ideas for the future. Prof. Richard Bardgett from the University of Manchester focused on soil biodiversity for soil health. Mixed plant communities with diverse root systems can resist drought through soil microbial mediation (Bardgett & Caruso, 2020). Dr. Sara Place from Colorado State University reflected on animal health from a sustainability context. The status quo is unlikely to meet the challenges of the coming decades, and therefore, investment in research and development for sustainable ruminant systems will be required (Place, 2024). Dr. Frédéric Leroy argued for an alternative view of grasslands and human health. Currently, in the United States, the business-as-usual perspective of public discourse from human health science suggests radical abolishment of livestock, rewilding, a plants-only diet, and vegan ideology. However, a holistic approach to animal husbandry, involving more harmonic and richer types of human–animal–land interactions, suggests that future thinking should emphasize "more of the better" (Leroy et al., 2020). The XXV International Grassland Congress was reinforced by keynote speeches covering the five subthemes. Dr. Jin-Sheng He described grassland ecology with a focus on biodiversity and ecosystem functioning using examples from the Qinghai–Tibet Plateau in China. Dr. Johannes Isselstein articulated the historical and current roles that livestock and grasslands share for delivering ecosystem services, with particular emphasis from a long-term grazing experiment in Lower Saxony, Germany. Dr. Paulo Carvalho emphasized the role of grazing livestock in manipulating pasture quality and productivity with experiences from annual pastures in integrated crop–livestock systems deployed in southern Brazil. Dr. Amy Ganguli revealed thoughts on how scientists could speak more about maintaining the functionality of grassland ecosystems and not just about the livestock that are sustained on rangelands of the arid western United States. Dr. Dana Kelly highlighted some of the social challenges in grasslands, particularly those of gender and land ownership in developing countries around the world. The XXV International Grassland Congress was sharpened with 19 different thematic sessions having 4–6 presentations in each. Several of these thematic sessions were the source of the seven papers that appear in this special section. In a grassland ecology thematic session, grasslands exemplified the delivery of ecosystem services, including the capacity to store large reservoirs of soil organic carbon. One paper in this special section synthesized available literature on soil organic carbon changes with long-term grassland management in the southeastern United States (Silveira et al., 2024) and another paper presented new results of an unique calculation method to separate pedogenic from management-controlled soil organic carbon and nitrogen changes with long-term pasture management (Franzluebbers et al., 2023). In a grazing intensity experiment, the hypothesis that patches will lead to greater spatial variability in belowground biomass and soil organic carbon stocks was not validated (Komainda et al., 2023). Rather, greater plant species diversity with lower soil nutrient contents in short-patch areas and higher nutrient contents together with light competition in tall-patch areas appeared to offset each other. Under a variety of grassland management scenarios in the Swabian Alps of Germany, greater land use intensity with fertilization and frequent mowing reduced root growth and adversely affected soil structure (Kuka & Joschko, 2024). In the southeastern United States, bermudagrass (Cynodon spp.) is a prominent forage, but faces challenges. Baxter et al. (2024) outlined challenges from the bermudagrass stem maggot (Atherigona reversura Villeneuve), delayed green-up following winter dormancy, the deficit of sprig materials and trained personnel to plant sprigs, and the need for cold-tolerant varieties. Alfalfa (Medicago sativa L.) variety selection with genetic improvements is needed in regions with mild temperature and a long growing season to overcome abiotic and biotic stressors. Tucker et al. (2024) reviewed management for utilizing alfalfa as part of beef, dairy, and finishing systems, as well as identifying educational programming efforts and on-farm demonstrations to promote alfalfa as a component of the livestock diet, integration into grass-based systems, crop rotations, and wildlife use. Hume et al. (2024) described the stability of introduced Epichloë endophytes of ryegrass over a 7-year period in New Zealand dairy pastures. Some postcongress news to note is that a website containing congress proceedings has been developed. Currently, all papers from 1997 to 2023, including joint events with the International Rangeland Congress in 2008 (China) and 2021 (Kenya), are available at https://uknowledge.uky.edu/igc/, or simply search for "IGC Proceedings". In addition, video recordings of all the XXV International Grassland Congress oral sessions can be viewed at: https://www.youtube.com/@InternationalGrasslandCongress/videos. Delegates at the XXV International Grassland Congress were enriched with abundant grassland-relevant information. Expect to explore the roots of the grassland congress at the 100th anniversary of the first International Grassland Congress to be held in the same city as the first congress—Leipzig, Germany! We look forward to sharing experiences at this event.