High-resolution mapping of soil total phosphorus in China: Revealing spatiotemporal patterns and driving mechanisms

Soil total phosphorus (STP) is a key component of the terrestrial phosphorus cycle, and its spatial distribution pattern profoundly influences ecological security and the stability of food production. This study integrates 20,372 nationwide plot monitoring records and, based on the Random Forest algorithm, constructs a 1 km resolution layered spatiotemporal map of STP across China for the period 2000-2020. The results show that China's STP exhibits an overall "central high, northern-southern low" spatial pattern, with South China identified as a contiguous low‑phosphorus region (<0.4 g/kg). Vertically, STP decreases by approximately 25.8% with increasing soil depth. The study further reveals regional differentiation characteristics of STP variation: the mid‑temperate zone serves as the core area of phosphorus accumulation, while the middle‑lower Yangtze River region and the Sichuan Basin are identified as hotspots of phosphorus loss. Solar radiation (SR) is the main positive driver of phosphorus enrichment in plateau regions (affecting 29.1% of the national area, ca. 2.65 × 10⁶ km²), whereas wind speed is the primary negative driver of phosphorus loss in arid regions (affecting 32.7% of the national area, ca. 2.98 × 10⁶ km²). Temperature (Tmp) exhibits a bimodal regulatory pattern. This study systematically elucidates the integrated impacts of natural and anthropogenic factors on the spatiotemporal pattern of STP, proposes a multi‑scale analytical framework for soil phosphorus cycling, and provides both data support and scientific basis for the zonal management of phosphorus resources and sustainable agricultural development.