Fire–vegetation feedbacks potentially maintain global savanna and forest distributions. Accordingly, vegetation in savanna and forest ecosystems should have differential responses to fire, but fire response data for herbaceous vegetation have yet to be synthesized across biomes. Here, we examined herbaceous vegetation responses to experimental fire at 30 sites spanning four continents. Across a variety of metrics, herbaceous vegetation increased in abundance where fire was applied, with larger responses to fire in wetter and in cooler and/or less seasonal systems. Compared to forests, savannas were associated with a 4.8 (±0.4) times larger difference in herbaceous vegetation abundance for burned versus unburned plots. In particular, grass cover decreased with fire exclusion in savannas, largely via decreases in C₄ grass cover, whereas changes in fire frequency had a relatively weak effect on grass cover in forests. These differential responses underscore the importance of fire for maintaining the vegetation structure of savannas and forests.

Pasture-based livestock systems in Argentina’s Humid Pampas are increasingly confined to soils with shallow or mechanically restrictive horizons, limiting forage production even under favourable climates. Tall wheatgrass [Elymus elongatus (Host) Runemark] is one of the few forage species capable of enduring these environments. To better understand forage yield drivers, we assessed the impact of soil restrictions, water, and nitrogen availability. Shoot biomass, water and nitrogen uptake, and water and radiation use efficiency (WUE, RUE) were evaluated during autumn, spring, and summer over two years. Experimental factors included edaphic environment (differing in water-holding capacity and A-horizon thickness), water availability (rainfed vs. irrigated to potential evapotranspiration), and nitrogen (0 vs. 300 kg N ha⁻¹). Yield was challenged by the edaphic environment even under non-limiting resource supply. Water was clearly linked to yield only during summer stressful conditions, while nitrogen uptake was ever present through its impact on canopy development, thereby influencing WUE and RUE. This study demonstrates that forage yield is fundamentally constrained by the edaphic environment, with the magnitude of this response aligning with soil harshness and climatic drivers of yield.