The paper deals with quantitative aspects of solution ³¹P NMR spectra of soil humic acids (HA). The present level of knowledge makes the ³¹P NMR spectroscopy a reliable tool for analysis of P types in HA and/or alkaline soil extracts. Observing standard conditions of HA isolation and spectra measurement, the ³¹P NMR spectroscopy gives reproducible and quantitative results, important for studying phosphorus transformations in ecosystems. Further research will probably provide more accurate information on composition of individual P fractions of HA, which can be substantially helpful in interpretation of ³¹P NMR spectra. Simultaneously, with more exact interpretation of the spectra, we can expect more precise quantitative analysis of their spectra - in particular replacement of integration of spectral bands by their deconvolution.