It has been 75 years since ecologically and agriculturally important long-term experiments (LTEs) were established at UKZN’s Ukulinga Research Farm in Pietermaritzburg in 1950 by Professor JD Scott, the founder of the discipline of grassland science at the then-University of Natal. A recent review of the contributions of these living laboratories to sustainable management and student training underscores their ongoing scientific value.
The LTEs are in a species-rich grassland with scattered trees and have provided important insights into how fire, grazing and soil nutrients shape ecosystems.
Understanding grasslands and savannas, which cover more than 60% of South Africa, is essential, as these ecosystems are not only a vital source of forage for wildlife and livestock but also provide services such as water regulation, carbon storage, biodiversity, cultural resources, and recreation.
The long-term experiments (LTEs) consist of two major studies: the Veld Burning and Mowing Trial and the Veld Fertilisation Trial, internationally known as the Ukulinga Grassland Fire Experiment and the Ukulinga Grassland Nutrient Experiment. Originally designed to run for at least 25 years to improve hay yield and forage quality, they have continued far beyond their initial scope and now serve as globally significant ecological research platforms.
They are the longest-running fire experiment in the world and the longest-running nutrient addition experiment in Africa, making them a unique ecological asset to UKZN.
Findings from the grassland fire experiment have greatly advanced our understanding of how burning applied at different frequencies and in different seasons interacts with summer mowing regimes to shape the composition, species diversity, and productivity of fire-dependent grasslands. Long-term exclusion of both fire and mowing leads to woody thickening and altered ecosystem function, whereas regular burning or mowing maintains diverse and productive grasslands. Nutrient additions increase productivity but favour fast-growing species and reduce diversity. These results, and others from the Ukulinga LTEs, have provided useful evidence to guide judicious and sustainable management of grassland and have provided valuable long-term insights into the ecological response and resilience of mesic grassland to disturbance. In a publication in the African Journal of Range & Forage Science, UKZN’s Professor Kevin Kirkman and Mr Craig Morris identified 50 peer-reviewed papers emanating from the LTEs that have been published. The top 10 most cited papers from research done on the Ukulinga LTEs have been cited in 458 journals by 1172 authors from 78 countries outside South Africa. Morris and Kirkman concluded that the LTEs have contributed to ecological theory, shaped local management practices, and supported a wide range of comparative studies, networking and education.
Topics researched on the LTEs have included fire effects, nutrient cycling, soil processes, biodiversity responses, and remote sensing, and have attracted international collaboration with US and European scientists to conduct comparative and collaborative studies that connect local observations to international ones, while highlighting the uniqueness of southern African grasslands.
Apart from the valuable science produced from the Ukulinga LTEs, they have also played a major educational and outreach role, training generations of students and influencing policy, conservation and grassland management across South Africa. For many undergraduate and postgraduate students, the grassy Ukulinga plateau was a classroom under the open sky, in the fresh air filled with grassbird song, raptors occasionally soaring above, where they learned to identify grasses and assess species composition, often ending the day with a swim in the reservoir.
Experiments established more recently on the Ukulinga plateau are part of globally distributed research networks, where the same treatments are applied across multiple countries and environments. These include the Nutrient Network (NutNet), the Drought Network (DroughtNet), and the Disturbance and Recovery Across Global Grasslands Network (DragNet), which enable international comparison and collaboration, linking local findings to global grassland research.
As the UN-designated International Year of Rangelands and Pastoralists (IYRP) approaches in 2026, Ukulinga can provide vital evidence of the roles of rangelands in food security, biodiversity, and climate resilience, informing policy and training future scientists. Preserving the Ukulinga LTEs and maintaining their original treatments will ensure ongoing insights into long-term ecological responses, support new research, and guide sustainable grassland management.
Words: Christine Cuénod & Craig Morris
Photograph: Debbie Jewitt (Ezemvelo KZN Wildlife)