Resolving chemical/biological drivers of P behavior around lowland/flooded rice roots remains a challenge because of the heterogeneity of the plant–soil interactions, compounded by sampling and analytical constraints. High-spatial-resolution (sub-mm) visualization enables these processes to be isolated, characterized, and deciphered. Here, three advanced soil imaging systems, diffusive gradients in thin-film technique coupled with laser ablation-ICPMS (DGT-LA-ICPMS), O₂ planar optode, and soil zymography, were integrated. This trio of approaches was then applied to a rice life cycle study to quantify solute-P supply, through two dimensions, in situ, and low-disturbance high-resolution (HR) chemical imaging. This allowed mechanisms of P release to be delineated by O₂, Fe, and phosphatase activity mapping at the same scale. HR-DGT revealed P depletion around both living and dead rice roots but with highly spatially variable Fe/P ratios (∼0.2–12.0) which aligned with changing redox conditions and root activities. Partnering of HR-DGT and soil zymography revealed concurrent P depletion and phosphatase hotspots in the rhizosphere and detritusphere zones (Mantel: 0.610–0.810, p < 0.01). This close affinity between these responses (Pearson correlation: −0.265 to −0.660, p < 0.01) cross-validates the measurements and reaffirms that P depletion stimulates phosphatase activity and P_org mineralization. The μ-scale biogeochemical landscape of rice rhizospheres and detritusphere, as documented here, needs greater consideration when implementing interventions to improve sustainable P nutrition.

中文翻译：

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结合多种高分辨率原位技术了解水稻根部周围磷的可用性

由于植物-土壤相互作用的异质性，再加上采样和分析的限制，解决低地/水淹水稻根部磷行为的化学/生物驱动因素仍然是一个挑战。高空间分辨率（亚毫米）可视化使这些过程能够被隔离、表征和破译。在这里，集成了三种先进的土壤成像系统、薄膜技术中的扩散梯度与激光烧蚀-ICPMS (DGT-LA-ICPMS)、O ₂平面光极和土壤酶谱相结合。然后将这三种方法应用于水稻生命周期研究，通过二维、原位和低干扰高分辨率 (HR) 化学成像来量化溶质 P 的供应。这允许 P 释放机制由 O ₂描述、Fe 和磷酸酶活性在同一尺度上作图。HR-DGT 揭示了水稻活根和死根周围的 P 消耗，但具有高度空间可变的 Fe/P 比（~0.2-12.0），这与氧化还原条件和根活动的变化一致。HR-DGT 和土壤酶谱的结合揭示了根际和碎屑圈区域中同时存在的 P 消耗和磷酸酶热点（Mantel：0.610-0.810，p < 0.01）。这些反应之间的这种密切关系（Pearson 相关性：-0.265 到 -0.660，p < 0.01）交叉验证了测量结果并重申 P 消耗会刺激磷酸酶活性和 P _org矿化。如本文所述，在实施干预措施以改善可持续磷营养时，需要更多考虑水稻根际和碎屑层的 μ 尺度生物地球化学景观。