Improved soil testing system in the Czech Republic: New valuation of micronutrients content in soil and phosphorus content in carbonate soils

Abstract

The official systematic soil testing system in the Czech Republic has practically 60 years duration – since 1961 is provided for needs of state administrative body and simultaneously for farmers. The extraction procedure Mehlich 3 is the official analytical method presently used (since 1999) in this soil testing system for the determination of available macronutrients (P, K, Mg, Ca). On the ground of uniformity, suitability and relatively cheap process of this analytical procedure, Mehlich 3 extractant can be used for a multiple-element extraction from soils, including determination available micronutrients (B, Cu, Zn, Mn, Fe). On the other hand Mehlich 3 extractant has some limits for right determination of available phosphorus content in carbonate soils (i.e. soils with pH value 7.2 and higher and simultaneously with content of available calcium 3500 and more mg kg -1 of soil). Extraction method Mehlich 3 used for determination of available phosphorus, usually doesn ́t indicate real phosphorus content in carbonate soils. There is content of available phosphorus more or less undervalued according to valid limits (criteria) for all soils. New, updated criteria of valuation of available phosphorus content in carbonate soils will be used for elimination of this incorrectness.