Further refinement of the soil potassium supplying, power evaluation considering mobile K along with soil clay and organic matter content. Procedure and significance for practical advisory work
1996
Bogaci, R. | Borlan, Z. (Institutul de Cercetari pentru Pedologie si Agrochimie, Bucharest (Romania))
An insight of the soil potassium supplying power evaluation currently used by soil chemical testing labs from Romania is given. It is considered that the existing pattern of interpretation, based solely on mobile K content (extraction with acetic acid - ammonium lactate slightly buffered at pH 3,7 - AL solution and correspondingly KAL according to Egner-Riehm-Domingo, 1960), though calibrated against plant response to K fertilizers in field trials, is adequate only for a range of soil textures (12-33 per cent of 2 microparticles) and organic matter content ( 8 per cent O.M.). Equivalent KAL values for soils with varied textures ( 5; 5-12; 12-33 and 33 per cent of clay 2 microns) and organic matter contents ( 8 and 8-30 per cent) were estimated by means of a potassium mobility index (KMI) determined as KCaCl2 0.01 M power /K AL (K intensity K quantity) considering average KMI for soils containing 12-33 per cent of clay 2 microparticles and less than 8 per cent O.M. as reference values. Further on, dividing KMI by the reference values, some KAL correction coefficients (CC) were calculated (table 1). Equivalent KAL values have resulted as a product of the analytically determined KAL and the corresponding CC (table 2). To estimate soil derived efficient K (Ks) (having the same yield forming efficiency as fertilizer derived K), using equivalent KAL values, exponent Cp in the regression equation (1) needs to be divided by CC.
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