Preliminary lessons from the GLENCOE farmlets: early trajectories of intensified grazing management on basaltic native grasslands

Abstract Long-term experiments are essential for understanding grazing systems because many critical processes, such as plant biodiversity shifts and soil organic carbon sequestration, occur over decades rather than years. Native grassland-based livestock systems of the South American Campos biome is inherently complex and variable, requiring management approaches that balance productivity and sustainability with climatic variations over time. The GLENCOE long-term experimental platform was established in 2023 by INIA Uruguay to evaluate how increasing levels of grazing management intensity shape productivity and sustainability system trajectories under real production conditions. The GLENCOE long-term experimental platform comprises three independent farmlets of 50 ha each with different levels of paddock subdivision: Farmlet 2P comprises fewer spatial and temporal decisions (two paddocks) and is considered the reference for the livestock system; Farmlet 8P is intermediate (eight paddocks), and Farmlet 32P has more spatial and temporal decisions (32 paddocks). The increase in the number of paddocks entails an increase in monitoring of pasture structure and decision-making of how to graze. A distinctive feature of the long-term experiment is its co-innovation approach, involving a support group composed of producers, extension agents, and researchers, which underpins strategic adaptive management and promotes collective evaluation of outcomes. Early results from the first three years indicate seasonal patterns and different trajectories among systems, particularly in canopy height, livestock carrying capacity, animal live weight and body condition, while wool production and quality remained similar. These findings highlight the role of grazing management intensity in buffering climatic variability and shaping early system dynamics.