Soil acidity governs cropland phosphorus availability under future climate

Tianyi Qiu, Shushi Peng, Daniel S. Goll, Jay Ram Lamichhane, Cesar Terrer, Xianjin He, Yongxing Cui, Ji Liu, Qingliang Cui, Shuling Zhao, Li Chen, Quanling Yang, Roland Bol, Pete Smith, Linchuan Fang

Understanding the response of agricultural phosphorus (P) cycling to climate change is fundamental for ensuring global food security and protecting planetary boundaries1–2. Recently, Wang et al.3 reported a drastic reduction in soil P bioavailability (32–34%) under long-term elevated carbon dioxide (eCO2) and warming in rice paddies, attributing it to enhanced geochemical sequestration via iron–organic carbon (Fe–OC) complexes. While we laud their decade-scale free-air CO2 enrichment experiment for providing compelling insights into Fe–OC-mediated P immobilization, we argue that the extent to which this mechanism can be generalized across broader croplands is limited. By synthesizing global observations encompassing both paddy and non-paddy fields, we demonstrate that this climate-driven P risk is highly context-dependent and gated by environmental acidity, rather than an inevitable consequence of future climate change—with only about one-eighth of croplands worldwide vulnerable to such severe exposure.