Unraveling four decades of soil acidification on the Qinghai-Tibetan Plateau: Patterns, drivers, and future projections.
Journal:
Environmental pollution (Barking, Essex : 1987)
Published Date:
May 2, 2025
Abstract
Soil acidification poses escalating threats to ecosystem functions, yet its spatiotemporal dynamics and drivers across vulnerable high-altitude regions remain poorly resolved. Here, we integrate four-decade soil surveys (1980s-2020s) with machine learning to unravel acidification trajectories and future projections for the Qinghai-Tibetan Plateau (QTP), a critical yet fragile alpine ecosystem. Our analyses reveal pronounced east-west divergence: persistent acidification dominates eastern alpine meadow grasslands (lower pH, negative ΔpH), constrasting with alkalization trends in western steppe grasslands (higher pH, positive ΔpH). Temporally, soil acidification accelerated over decades, evidenced by decling pH of 7.95 in the 1980s to 7.90 in the 2020s, and increasingly negative ΔpH of -0.02 during 1980s-2000s to -0.03 during 2000s-2020s. Vertical stratification highlights surface-layer vulnerability, with the most rapid pH decline in top-surface layer and maximum acidification ΔpH magnitude in middle-surface layer. Key drivers include mean annual precipitation, aboveground gross primary productivity, and nitrogen deposition. All inversely correlated with pH. Future projections under different scenarios predict accelerated acidification, most serve underSSP5-8.5 and moderated under SSP1-1.9. These findings highlight the vulnerability of QTP grasslands to multifactorial acidification, urging targeted mitigation strategies to preserve this ecologically pivotal region.
