ABSTRACT Soil phosphorus (P) loss risk and environmental impact can be assessed by different soil test indicators such as soil P storage capacity (SPSC), a site-specific and reliable measurement of soil P status. In this study, the changing trends of soil P saturation ratio (PSR) and SPSC in red soil (equivalent to Ultisol) were discussed after 10 consecutive additions of P solution with 20 mg P L−1, and the relationships between Olsen-P, CaCl2-P, and PSR, SPSC also were evaluated. Results showed that the soil PSR was increased to 0.22 at the end of P addition, and the accumulated P was high to 1625 mg kg−1. The threshold PSR of the red soil was determined to be 0.10, and the SPSC significantly decreased from 242.0 mg kg−1 to −382.1 mg kg−1 with the increase of P addition times. When SPSC = 0, the accumulated P in red soil was 487.7 mg kg−1. Therefore, there existed four stages for the soil P management in red soil according to the changes of SPSC and Olsen-P: short supply stage of soil P (SPSC>88 mg kg−1 and Olsen-P ≤ 20 mg kg−1), stable supply stage of soil P (68 mg kg−1< SPSC≤88 mg kg−1 and 20 mg kg−1< Olsen-P ≤ 40 mg kg−1); over supply stage of soil P (0< SPSC≤68 mg kg−1 and 40 mg kg−1< Olsen-P ≤ 108 mg kg−1), and the high loss risk stage of soil P (SPSC≤0 and Olsen-P > 108 mg kg−1). In the last stage, P fertilization must be stopped and environmental protection measures must be taken immediately.

中文翻译：

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Ultisol 中重复添加磷对土壤磷储存能力的影响

摘要 土壤磷 (P) 损失风险和环境影响可以通过不同的土壤测试指标进行评估，例如土壤磷储存能力 (SPSC)，这是一种特定地点且可靠的土壤磷状况测量。本研究讨论了连续添加 10 次含 20 mg PL−1 的 P 溶液后红壤（相当于 Ultisol）中土壤 P 饱和比（PSR）和 SPSC 的变化趋势，以及 Olsen-P、CaCl2 之间的关系-P 和 PSR、SPSC 也进行了评估。结果表明，施磷结束时土壤 PSR 增加到 0.22，累积 P 高达 1625 mg kg-1。红壤的阈值PSR被确定为0.10，随着P添加次数的增加，SPSC从242.0 mg kg-1显着降低到-382.1 mg kg-1。当 SPSC = 0 时，红壤中累积的 P 为 487.7 mg kg−1。因此，根据SPSC和Olsen-P的变化，红壤土壤磷管理存在四个阶段：土壤P短缺阶段（SPSC>88 mg kg-1和Olsen-P ≤ 20 mg kg-1） , 土壤磷的稳定供给阶段（68 mg kg−1< SPSC≤88 mg kg−1 和20 mg kg−1< Olsen-P ≤ 40 mg kg−1）；土壤磷过量供给阶段（0< SPSC≤68 mg kg−1 和 40 mg kg−1< Olsen-P ≤ 108 mg kg−1），土壤磷高流失风险阶段（SPSC≤0 和 Olsen- P > 108 mg kg-1)。在最后阶段，必须停止施磷，并立即采取环保措施。Olsen-P ≤ 40 mg kg−1)；土壤磷过量供给阶段（0< SPSC≤68 mg kg−1 和 40 mg kg−1< Olsen-P ≤ 108 mg kg−1），土壤磷高流失风险阶段（SPSC≤0 和 Olsen- P > 108 mg kg-1)。在最后阶段，必须停止施磷，并立即采取环保措施。Olsen-P ≤ 40 mg kg−1)；土壤磷过量供给阶段（0< SPSC≤68 mg kg−1 和 40 mg kg−1< Olsen-P ≤ 108 mg kg−1），土壤磷高流失风险阶段（SPSC≤0 和 Olsen- P > 108 mg kg-1)。在最后阶段，必须停止施磷，并立即采取环保措施。