China's dryland soil quality: Past, present, and future

Soil quality serves as the cornerstone supporting the stability, biodiversity, and multifunctionality of dryland ecosystems. However, the evolution (past and present) and future trends of soil quality in dryland regions under global change remain largely unexplored. Here, we conducted a large-scale field survey across 248 sites spanning more than 4000 km geographical distance in China’s drylands–one of the world’s largest dryland regions, with the focus on long-term land treatments over the past four decades. Our findings revealed that China’s drylands have undergone a profound transformation since the initiation of large-scale land treatments in 1980, as evidenced by reduced desert areas, expanded vegetation cover, and improved soil quality. Compared to sites with no treatments, the land treatments substantially enhanced soil nutrient stocks, nutrient availability, and overall soil quality by 13%–289%, with the climate being another influencing factor. As an unintended but beneficial consequence of land treatments, widespread development of biological soil crusts (biocrusts) has further reinforced these improvements in soil quality. We also found that the land treatments would mitigate the future loss of soil quality expected to be caused by increasing aridification and grassland degradation. Together, our findings highlight the positive role of anthropogenic land treatments in improving soil quality in vast dryland regions.