Total phosphorus and nitrogen were also measured in soil by ion chromatography after microwave digestion with hydrogen peroxide. The humic fraction of organic matter was extracted using a sodium pyrophosphate/sodium hydroxide extraction method. The resulting humic acid was analysed by 13C solid state NMR and pyrolysis GC-MS. Exchangeable cations were analysed by ICP-OES on ammonium chloride extracts. Total organic carbon was determined by a wet oxidation method and measured by UV-Vis spectroscopy. A further comparison was made with the soil solution obtained from these sites.
This paper will present a detailed analysis of the results of this study, highlighting the differences between sites of different vegetation age, with a particular emphasis on the relationship between soil organic matter and nutrient retention.