Purpose

Phosphorus (P) and silicon (Si) mobility and their interactions in soils are sensitive to soil pH. Although Si fertilizer application has been reported to efficiently increase P availability in soils, the responses of Si mobility and availability to soil P enrichment are not well understood.

Materials and methods

This study investigated the effects of P addition and artificial soil acidification on Si sorption and availability in a Hydragric Anthrosol using adsorption, soil incubation, and rice growth pot experiments.

Results and discussion

When Si and P were simultaneously added at equimolar concentrations between pH 3.5 and 6.5, the presence of P decreased Si adsorption by 22–88% at the corresponding pH, suggesting that P had a greater affinity to soil solids than did Si. Si sorption by the soil generally increased with pH increasing in the pH range of our study, and the reduction of Si sorption due to P addition was more significant under higher pH conditions (e.g., CK (soil without pH adjustment, pH = 6.4) and pH 5.5 treatments). Soil acidification and P addition that decreased Si sorption resulted in greater Si mobility and availability, as indicated by higher soil CaCl₂-extractable Si content and greater Si uptake and Si content of rice plant.

Conclusions

Our results highlight the importance of Si mobility or loss due to P enrichment and soil acidification in weathered soils used for Si-accumulating plants such as rice.

中文翻译：

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土壤酸化和磷富集增强了 Hydragric Anthrosol 中的硅迁移率

目的

磷 (P) 和硅 (Si) 迁移率及其在土壤中的相互作用对土壤 pH 值敏感。尽管据报道施用硅肥可有效增加土壤中磷的有效性，但硅迁移率和有效性对土壤磷富集的响应尚不清楚。

材料和方法

本研究使用吸附、土壤培养和水稻生长盆栽实验研究了磷添加和人工土壤酸化对水草土壤中硅吸附和有效性的影响。

结果和讨论

当在 pH 3.5 和 6.5 之间以等摩尔浓度同时添加 Si 和 P 时，P 的存在在相应的 pH 下使 Si 吸附减少 22-88%，表明 P 对土壤固体的亲和力大于 Si。在我们研究的 pH 值范围内，土壤对 Si 的吸附通常随着 pH 值的增加而增加，并且在较高的 pH 条件下（例如，CK（未经 pH 调节的土壤，pH = 6.4）和pH 5.5 处理）。土壤酸化和 P 添加降低 Si 吸附导致更大的 Si 迁移率和可用性，如土壤 CaCl _{2 可}提取的 Si 含量更高以及水稻植物的 Si 吸收和 Si 含量更高表明。

结论

我们的研究结果强调了在用于积硅植物（如水稻）的风化土壤中，由于 P 富集和土壤酸化，Si 迁移或损失的重要性。