Evaluating the capacity and loss risk of soil nutrients is helpful to make fertilization strategies. Herein, the term of soil potassium (K)-holding capacity (SKHC) was put forward to assess the capacity and loss risk of plant-available K of specific soils. In this study, SKHC was evaluated via soil waterlogging-simulation experiments using 14 different soils. The K concentrations in surface water were measured, and a critical K concentration was selected to indicate high soil K loss. Results showed that the surface water K concentration (K_sw) was significantly affected by waterlogging time, temperature, and soil thickness. The average K_sw of 5-cm soil columns waterlogged for 24 h for the 14 soils was 5 mg L^–1 (1.57–8.57 mg L^–1); this was subsequently used as the critical K concentration. By repeating the waterlogging simulation experiment with soils treated with different rates of K fertilizer, a quadratic relationship between the K rate and K_sw was found and used to determine the K rate required making the K_sw reach the critical K concentration. For the 14 soils, SKHC ranged from 133 to 2,054 mg kg^–1 and can be classified into four levels: low, <500 mg kg^–1; moderate, 500–1,000 mg kg^–1; high, 1,000–1,500 mg kg^–-1; and extremely high, >1,500 mg kg^–1. These results allowed the preliminary establishment of an SKHC evaluation method and grading system. Future studies should verify the SKHC under field conditions and optimize the assessment method proposed in this study.

中文翻译：

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基于模拟涝渍试验的土壤持钾能力评价

评估土壤养分的容量和损失风险有助于制定施肥策略。在此，提出土壤钾（K）持水量（SKHC）这一术语来评估特定土壤植物速效钾的容量和损失风险。在这项研究中，通过使用 14 种不同土壤的土壤涝渍模拟实验对 SKHC 进行了评估。测量了地表水中的 K 浓度，并选择了一个临界 K 浓度来表示高土壤 K 损失。结果表明，地表水钾浓度（K _sw）受涝渍时间、温度和土壤厚度的显着影响。14 种土壤浸水24 小时的 5 厘米土柱的平均 K _sw为 5 mg L ^–1 (1.57–8.57 mg L ^–1); 这随后被用作临界 K 浓度。通过对不同施钾量的土壤重复进行涝渍模拟试验，发现了钾肥率与K _sw之间的二次关系，并用于确定使K _sw达到临界K 浓度所需的钾肥率。对于这 14 种土壤，SKHC 的范围从 133 到 2,054 mg kg ^–1并可以分为四个级别：低、<500 mg kg ^–1；中等，500–1,000 mg kg ^–1；高, 1,000–1,500 mg kg ^---1 ; 并且极高，>1,500 mg kg ^–1. 这些结果使SKHC评价方法和分级体系初步建立。未来的研究应在现场条件下验证 SKHC 并优化本研究提出的评估方法。