• Free amino acids;
  • heathland soil;
  • nitrogen nutrition;
  • Calluna;
  • mycorrhiza


The soil of a typical upland Callunetum was fractionated and the concentrations of nitrogenous components determined, emphasis being placed upon analysis of the distribution of ‘free’ amino acids both down the soil profile and through the year. The largest quantities of free amino-compounds at all times of the year were found at the top of the profile, peak values occurring in September, October and November. Quantities of amino acids often exceeded those of extractable ammonium. The results are compared with those obtained in earlier studies of acidic organic soils and the significance of the findings is discussed with special reference to the nitrogen nutrition of mycorrhizal and non-mycorrhizal ericaceous plants.