Comparison of methods for available soil nutrient determination in Czech Republic, Latvia, Poland, Slovak Republic and United Kingdom
2000
Bujnovsky, R. | Bhogal, A. | Cermak, P. | Fotyma, M. | Igrasz, J. | Jadczystyn, T. | Karlins, A. | Machacek, V. | Miklovic, D. | Shepherd, M.
Comparison of analytical methods for available soil nutrients determination brought several experiences as follows: 1. Extracted amount of available P decreases in order Mehlich III Mehlich II Egner-Riehm DL Olsen Pi CaCl2 (expressed in index 100 - 85 - 76 - 32 - 12 - 2). 2. Average amount of available potassium is decreasing in order Mehlich III Mehlich II = Kex NH4NO3 /= Egner-Riehm DL CaCl2 (index values are 100 - 91 - 91 - 82 - 79 - 40). 3. Methods' Mehlich II and III are estimating practically whole amount of exchangeable potassium (Kex) in soil sorption complex. Contraty, method (0.01 M) CaCl2 correlates with exchangeable K values at least of all. 4. Average amount of available magnesium decreases in order Mehlich III /= Mehlich II/= Mgex 1 M KCl/= NH4NO3 0.01 M CaCl2 or 0.0125 M CaCl2 (in index expression 100 - 96 - 93 - 79 - 73 - 56). 5. Available Mg content determined by Mehlich II and Mehlich III method is close to values of exchangeable Mg (Mgex) in soil sorption complex. Witch some distance follow the methods NH4NO3 and KCl, estimating approximately 70% of exchangeable Mg. The last is the Schachtschabel or 0.01 M CaCl2 method that estimates less than half of exchangeable magnesium (Mgex). In most cases we may state the great variability at evaluation of avilable nutrient content within one category of soil supply that confirm also high values of coefficient of variability (usually over 30%). Czech and Slovak criteria for evaluation of Mehlich III method results show small differences despite some differences in structure of calibration scheme
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