In the past several decades, China’s agricultural soils have undergone a significant transformation, marked by increasing acidity that threatened both crop yields and ecological integrity. This troubling trend, largely attributed to the extensive use of chemical nitrogen fertilizers and industrial emissions, has raised alarms within the scientific and agricultural communities. These inputs, while essential to sustain China’s large population through enhanced food production, have inadvertently contributed to soil acidification, a condition detrimental to soil fertility and long-term agricultural sustainability. However, a recent groundbreaking study published in Nature Geoscience offers a radically optimistic update: the widespread acidification of China’s cropland soils has, in fact, ceased.
The research, spearheaded by Profs. YAO Yijun and LUO Yongming from the Institute of Soil Science at the Chinese Academy of Sciences, meticulously documents how the steady decline in soil pH levels—first observed in the 1980s—stabilized around 2013. This cessation is closely linked to comprehensive agricultural policy reforms enacted by the Chinese government, which aimed to optimize nitrogen fertilizer usage. By refining application rates and timing, these policies have not only curbed excessive nitrogen inputs but also mitigated the soil’s progressive acidification over time.
To underpin this conclusion, the researchers amalgamated data from an unprecedented 7,024 regional soil surveys conducted between 1985 and 2022. This extensive dataset represents the largest topsoil pH compilation in China’s agricultural history. Employing an advanced machine-learning model, the team analyzed spatial and temporal shifts in soil acidity across diverse cropland types. Their findings demonstrate a cumulative decline of approximately 0.25 pH units between 1985 and 2013, after which the decline plateaued.
Importantly, the study highlights differential recovery trajectories between distinct farmland categories. Paddy fields, characterized by flooded conditions, have exhibited early signs of pH rebound since 2013, suggesting a partial reversal of acidification. In contrast, dryland soils, predominant in Northern and Western China, have remained largely static, with minimal observable recovery. This disparity may be rooted in the contrasting biogeochemical processes governing these soil types, including differences in drainage, microbial activity, and buffering capacity.
The implications of these findings challenge previous assumptions that soil acidification in China would persist unchecked without drastic intervention. According to Prof. YAO, the halt in pH decline directly correlates with agricultural input adjustments, underscoring the efficacy of evidence-based policy in environmental management. This serves as a potent example of how targeted governance, coupled with scientific monitoring, can pivot long-standing environmental trends on a national scale.
Looking forward, projections derived from the machine-learning model suggest that despite continued reductions in nitrogen fertilizer application, soil pH recovery to pre-acidification levels of the 1980s remains unlikely by the year 2040. This prognosis is particularly somber for dryland soils, which possess intrinsically low natural buffering capacities and are more susceptible to persistent acidification effects. The slow pace of recovery highlights the challenge of reversing soil degradation once established and calls for innovative rehabilitation strategies beyond mere fertilizer reduction.
The research team advocates for regionally tailored soil management practices designed to catalyze soil health restoration. These strategies may include the incorporation of organic fertilizers, providing more balanced nutrient inputs alongside soil organic matter enhancement. Additionally, the use of controlled-release nitrogen fertilizers can further modulate nutrient availability, minimizing leaching and acidifying impacts. Such integrated approaches aim to improve soil resilience while safeguarding agricultural productivity.
This study not only traces historical soil acidification patterns but also introduces a dynamic modeling framework enabling near real-time monitoring of soil health across expansive agricultural landscapes. By integrating vast empirical datasets with cutting-edge analytical techniques, the framework facilitates proactive soil management decisions, optimizing fertilizer use efficiency and environmental outcomes.
The broader ramifications extend well beyond China’s borders. As a global leader in agricultural production, China’s experiences and policy interventions offer valuable insights for other countries grappling with similar soil degradation challenges. The research underscores the critical role of interdisciplinary collaboration — linking soil science, agronomy, policy analysis, and data science — in addressing complex sustainability issues within agriculture.
In conclusion, the stabilization of acidification in China’s cropland soils signals a turning point in the narrative of soil health management. The study exemplifies how science-driven policy reforms can halt environmental degradation on a massive scale. Nevertheless, the path to full soil recovery involves persistent efforts, adopting holistic and location-specific practices that go beyond fertilizer regulation. This work stands as a beacon of hope for sustainable agriculture and long-term food security, illuminating pathways to preserve and restore the fertile foundation upon which human civilization depends.
Subject of Research: Not applicable
Article Title: Stabilization of acidification in China’s cropland soils
News Publication Date: 14-Oct-2025
Web References: 10.1038/s41561-025-01813-1
Keywords: Cropland, Fertilizers, Soil acidification, Soil fertility, Agriculture, Sustainable agriculture
