The nonexchangeable potassium (neK) content of 178 agricultural soils in Japan was determined by subtracting the amount of K extracted with 1 mol L −1 ammonium acetate, i.e., exchangeable K (exK) from that extracted with boiling 1 mol L −1 HNO 3. The statistical relationships between the neK content and physico-chemical properties of the soils were examined to investigate the factors controlling neK content. The neK content of agricultural soils in Japan ranged from 0 to 1120 mg kg −1 with an arithmetic mean and median of 303 and 255 mg kg −1 , respectively. It showed a significant positive correlation with the total K content, fixed ammonium content, and silt content (p < 0.01) and a significant negative correlation with Alo+1/2 Feo content and total carbon content (p < 0.01). These results suggest that the controlling factors of neK are mainly the total K content and 2:1 type phyllosilicates such as mica and vermiculite, with the indirect negative influence of organic matter and amorphous materials. Terrestrial Regosols, Brown Lowland soils, and Dark Red soils had relatively high neK contents. In contrast, Andosols, Wet Andosols, and Volcanogenous Regosols had relatively low neK contents. The neK content showed no significant correlation with exK content, suggesting that neK is a moderately to slowly available fraction of soil K, which is independent of exK. In conclusion, evaluation of nonexchangeable K in combination with exchangeable K would enhance the rational management of agricultural soils in terms of K fertility by taking account of longer term K-supplying power of soils.

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Background Despite continuous developments and advances in the perioperative management of patients suffering from acute aortic dissection type A (AADA), the associated postoperative morbidity and mortality remain high and strongly depend on the preoperative clinical status. The associated postoperative mortality is still hard to predict prior to the surgical procedure. The so-called German Registry of Acute Aortic Dissection Type A (GERAADA) score uses very basic and easily retrievable parameters and was specifically designed for predicting the 30-day mortality rate in patients undergoing surgery for AADA. This study evaluated impact of the GERAADA score in the authors’ institutional results. Methods Among 101 acute type A aortic dissection patients treated at our hospital during August 2015–March 2021, the GERAADA was calculated individually and retrospectively. Predicted and actual mortalities were assessed, and independent predicted factors were searched. The primary endpoint was defined as comparison of GERAADA scores and early mortality, and the secondary endpoints were defined as comparison of GERAADA scores and other postoperative results, and comparison of preoperative factors and postoperative results regardless to GERAADA scores. Results While the overall 30-day mortality for the entire study cohort calculated by the GERAADA score was 14.3 (8.1–77.6)%, the actual mortality rate was 6%. However, the GERAADA score was significantly high in some postoperative complications and showed significant correlation with some peri- and post-operative factors. In addition, factors not belonging to GERAADA score such as time from onset to arrival at the hospital, time from onset to arrival at the operation room, spouse presence, and hemodialysis were significantly associated with 30-day mortality. Conclusions Although the actual mortality was lower than predicted, GERAADA score may impact on the postoperative course. In addition, it would be desirable to add parameters such as the time from onset to arrival, family background, and hemodialysis for further accuracy.

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