Plant-available soil phosphorus (P) is commonly assessed by chemical extractions with the purpose of diagnosing and advising fertilizer P application. However, for a given crop, this approach only poorly predicts yields obtained from several experimental sites. To solve this major drawback, a functional and mechanistic evaluation has been developed to mimic dominant processes involved in the absorption of phosphate ions. In this study, we investigated the predictive ability of a mechanistic approach to diagnose maize ( L.) yields, in comparison to the common Olsen's method (0.5 M bicarbonate solution). The processes-based assessment consists of parameterizing relationships between amount of diffusible phosphate ions () at the solid-to-solution interface equilibrating the phosphate ions concentration in solution () with time (). We parameterized [ vs. (, )] relationships for stored and archived soil samples (plough layer) of nine long-term field experiments (LTFEs) on increasing rates of P applications including the zero-P treatment (P0). LTFEs were located in different soils (Luvisol, Podzol, Arenosol, Calcosol) with large variations in physico-chemical properties. We also used LTFEs database of maize yields. The values ranged from 0.02 to 3.86 mg P L for 40 (LTFE×year of maize cropping) combinations. The (=v××) equation closely described the [ vs. (, )] datasets, with (v, w, p) parameters being soil specific. Maximum yields ranged from 5.5 to 14.7 t DM ha depending on LTFEs and years. Yields decreased significantly only in P0, and did not differ for other P rates. The relationship between the relative maize yield and was sites-specific with thresholds to obtain a relative yield of 0.95 ranged from 0.07 to 0.88 mg P L solution. Taking into account amounts of phosphate ions which balance by diffusion using (=v××) equations, a single response curve is observed for the 9 LTFEs when the replenishment time is 1500 minutes (i.e. about one day). The critical thresholds closely correlated to the ability of the soil solid phase to buffer phosphate ions in solution. For the 9 studied LTFEs on P fertilization, the [ vs. (, )] relationships were more able to account for maize response curves than P extracted by Olsen method, improving the precision and reliability of the multisite diagnosis of maize yield response. As a result, P fertilization recommendations are more reliable regardless of soil type. Further progress could be gained by taking into account for the role of the soil layer beneath the plough layer.

中文翻译：

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植物有效土壤磷的功能和机制评估极大地改善了玉米产量响应的多点诊断


植物可利用的土壤磷 (P) 通常通过化学提取进行评估，目的是诊断磷肥施用并提供建议。然而，对于给定的作物，这种方法只能较差地预测从多个实验地点获得的产量。为了解决这个主要缺点，开发了功能和机械评估来模拟磷酸盐离子吸收中涉及的主要过程。在本研究中，我们研究了机械方法诊断玉米 (L.) 产量的预测能力，并与常见的 Olsen 方法（0.5 M 碳酸氢盐溶液）进行比较。基于过程的评估包括参数化固体与溶液界面处的可扩散磷酸根离子 () 的量 () 之间的关系，平衡溶液 () 中的磷酸根离子浓度与时间 ()。我们参数化了九个长期田间试验（LTFE）中存储和存档的土壤样本（犁层）的[与（，）]关系，以提高磷施用率，包括零磷处理（P0）。 LTFE 分布在不同的土壤（Luvisol、Podzol、Arenosol、Calcosol）中，其物理化学性质差异很大。我们还使用了玉米产量的 LTFE 数据库。 40 个（LTFE × 玉米种植年份）组合的值范围为 0.02 至 3.86 mg PL。 (=v××) 方程密切描述了 [ 与 (, )] 数据集，其中 (v, w, p) 参数是特定于土壤的。最大产量范围为 5.5 至 14.7 吨 DM ha，具体取决于 LTFE 和年份。仅 P0 产量显着下降，其他 P 率没有差异。相对玉米产量与获得 0.95 相对产量的阈值之间的关系是特定地点的，范围为 0.07 至 0.88 mg PL 溶液。 考虑到使用(=v××)方程通过扩散平衡的磷酸根离子的量，当补充时间为1500分钟（即大约一天）时，对于9种LTFE观察到单一响应曲线。临界阈值与土壤固相缓冲溶液中磷酸根离子的能力密切相关。对于 9 个研究的磷施肥 LTFE，[ vs. (, )] 关系比 Olsen 方法提取的 P 更能解释玉米响应曲线，提高了玉米产量响应多点诊断的精度和可靠性。因此，无论土壤类型如何，施磷的建议都更加可靠。通过考虑耕作层下方土壤层的作用，可以获得进一步的进展。