engleski

Different P-tests as a part of model for fertilizer recommendations

The purpose of this paper was to create a model for improving fertilizer recomendations and to compare two different soil phosphorus tests. Extraction by ammonium lactate (AL-P, common soil test in Croatia) and by sodium bicarbonate solution (Olsen-P, recently standardized soil test in Croatia) were compared in 430 samples. Two results signifficantly correlated (r=0, 745) and the diference was influenced by soil pH. Model for predicting Olsen-P values using common soil data (pHH2O, pHKCl, organic matter, AL-P, AL-K) was validated with new data sets from field fertilization trials. Conductted analyses resulted in significant correlation between soil phosphorus extracted by sodium hydrogen carbonate solution (Olsen P) and by ammonium lactate (AL P). Also, the results showed that Olsen P can be used for fertilizing recomendations instead of AL P. Model will be improved by another P tests.

phosphorus ; soil test ; fertilization ; recommendation ; ammonium lactate ; sodium hydrogen carbonate

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