Berta-Szabó, E., Zsigrai, G., Szabó, A., & Loch, J. (2010). Effects of long-term K fertilization and liming on the extractable and exchangeable K contents of a Haplic Phaeosem soil. Acta Agraria Debreceniensis, (I), 141–145. Retrieved from https://ojs.lib.unideb.hu/actaagrar/article/view/8392
Effects of regular K fertilization and liming on the easily extractable K content of a Haplic phaeosem soil determined in 0.01 M CaCl2 and AL (traditional method in Hungary) were examined in the B1740 type of the National Uniformed Long-Term Fertilization Experiments at Karcag. Close correlation (r=0.95) was found between the 0.01 M CaCl2 and ammonium lactate - acetic acid (AL) extractable K contents of soils. K fertilization increased the amount of 0.01 M CaCl2 and AL extractable K significantly. Liming had different effects on the amounts of K extracted by these two methods. Liming increased the amount of AL-K and decreased the amount of CaCl2-K. CaCl2 extractable K was in close correlation with the relative amount of exchangeable K content of the soil (K%) and the agronomic K balance. The results of regression analysis confirmed that the CaCl2-K characterized K% and the AL-K related to the absolute amount of exchangeable K. On the basis of the presented results it can be stated that the 0.01 M CaCl2 is able to detect not just the increase of easily extractable K caused by fertilization and liming but the changing of the rate of the relative amount of exchangeable K.