Comparison of phosphorus, potassium, and magnesium contents determined with the universal, Egner-Riehm and Schachtschabel methods in orchard soils

摘要

The study was carried out in six orchards of Wielkopolska in the years 1997 - 1999. The content of phosphorus and potassium determined with the Egner-Riehm and magnesium with the Schachtschabel methods was compared to the universal method (0.03 M CH_3COOH extract). It was indicated that the mean contribution of phosphorus (P_U), potassium (K_U), and magnesium (Mg_U) determined by the universal method in relation to those of Egner-Riehm (P_(ER)) - (K_(ER)) and Schachtschabel (Mg_S) in orchard soils was 46.7%, 51.6%, and 71.3%, respectively. The contribution of P_U and Mgu was lower in the herbicide strips and amounted to 45.5% and 62.9%, respectively, than in the grass ones - 47.9% and 79.7%. The contribution of K_U was higher in the herbicide strips- reached 53.2% but in the grass ones it was 50.0%. With the increase in the depth soil sampling (0 - 20 and 20 - 40 cm) reduced the portion of K_U with respect to K_(ER) both in the herbicide and grass strips. No similar relationships were found for phosphorus and magnesium. Mean coefficients of recalculating the results from the universal into the Egner-Riehm and Schachtschabel methods are: P 2 14 (1.87 - 2.60), K 1.94 (1.79 - 2.28), Mg 1.40 (1.18 - 1.62); inversely: P 0.47 (0.38 - 0.54), K 0.52 (0.44 - 0.56), Mg 0.71 (0.62 - 0.85). Correlations were indicated between the determinations carried out with the universal and the Egner-Riehm and Schachtschabel methods. They were higher for phosphorus (0.69 - 0.94) and potassium (0.70 - 0.93) than for magnesium (0.29 - 0.42). The correlation coefficients varied depending on the method of soil cultivation in the orchard (herbicide, grass strips) and the depth of the analysed soil layers (0 - 20 and 20 - 40 cm). The study proved that the universal method can be successfully applied to chemical analyses of orchard soils.