Spatial Coordination of Phosphorus and Water Enhances Maize Growth and Phosphorus Uptake by Modifying Root Distribution

Phosphorus (P) and water are essential but often spatially mismatched resources in agricultural soils, limiting plant growth and nutrient uptake efficiency. Their low mobility and uneven distribution in the soil profile necessitate strategies that optimize their use, particularly through targeted management at the root‐soil interface. A split‐root experiment comprising six distinct combinations of P and water was conducted to assess how their spatial coordination influences maize ( Zea mays L.) growth, P uptake, and root development. Maize roots exhibit strong plasticity in response to spatial heterogeneity, preferentially proliferating in zones with simultaneous P and water availability. The co‐localized treatment (CWP) significantly increased total root length (TRL) and surface area by up to 189% and 208%, respectively, compared to treatments with P or water applied alone. Shoot biomass and shoot P content under the CWP treatment were also markedly enhanced, achieving levels comparable to those in the high‐input control despite a 50% reduction in P inputs. Additionally, root diameter analysis revealed a higher proportion of fine roots (< 0.2 mm) in P‐ and water‐enriched patches, indicating enhanced root foraging capacity. Phosphorus uptake per unit root length was also maximized under CWP treatment, matching levels observed in uniformly high P and water treatments, despite using half the inputs. Correlation analyses further confirmed positive relationships between TRL, shoot P content, and shoot biomass. These findings highlight the synergistic role of spatially coupled P and water supply in optimizing root/rhizosphere efficiency and maximizing nutrient acquisition. The study underscores the potential of precision nutrient‐water placement strategies to enhance agricultural sustainability by improving input efficiency and crop performance under variable soil conditions.