A relationship between multi-nutrient soil tests (Mehlich 3, ammonium acetate, and water extraction) and bioavailability of nutrients from soils for barley

The aim of the paper was to test the universality of three multi-nutrient soil tests after a radical intervention in soil chemistry by gypsum treatment on a variable set of 36 soils. Pot experiments with barley in a growth chamber were conducted to determine the bioavailability of K, Mg, P, Mn and B from soils. There were no marked differences in correlations between soil tests and the plant in K, Mg and P. But in the case of Mn and B Mehlich 3 test was not in appropriate agreement with the plant. Shortcoming of water extraction is missing information of capacity character for the derivation of the fertilizer recommendations on heterogeneous soils. The highest universality of NH4-acetate soil test was proved in all studied nutrients (K, Mg, P, Mn, B) in relation to the plant. Determination of the CEC value that extends the information of capacity character is a part of this soil test. The CEC value contributes to a more sophisticated approach to interpretation for the fertilizer recommendations.