PHOSPHORUS STATUS OF EUTRIC-CAMBISOLS POLLUTED BY P-CONTAINING IMMISSIONS - RESULTS OF P-31 NMR-SPECTROSCOPY AND CHEMICAL-ANALYSIS

The P status of an unpolluted Cambisol was compared with that of a pol luted Cambisol receiving high P deposition that arise from a fertilize r factory near Novgorod, NW Russia. Experiments included P fractionati on, P adsorption experiments and P-31 NMR spectroscopy. In the O, A an d AB horizons of the unpolluted soil organic P was the dominating frac tion. Anthropogenic P accumulation was restricted to the O, A and AB h orizons and amounted 692 kg ha(-1), representing the sum of P depositi on within 20 years of factory operation. Most of the additional P was extractable inorganic P. Hence, extractability increased from 54-75% i n the unpolluted soil to 66-83% in the polluted soil. Ca-phosphates we re mainly accumulated in the forest floor, while Al- and Fe-phosphates were concentrated in the A and AB horizons. Organic P showed only a s light increase due to P deposition. This increase was only due to accu mulation of stable monoester-P, while the stock of the more labile die ster-P and phosphonates in the polluted soil was only half of that in the unpolluted soil.