Natural forests of Quercus robur L. in Northwest Spain - main properties of soils

The main properties of the soils under oak (Quercus robur L.) forests in Galicia (NW Spain) were characterized. Eleven edaphic parameters (pH, OM, N, C/N ratio, P, K, Ca, Mg, sand, silt and clay) were estimated in 39 soil samples. Siliceous substrates were present in all stands and the soils were found to be the cambisols. The values of chemical parameters are similar to those considered as the optimal ones by other authors (i.e., average pH close to 5, average C/N ratio close to 15) with the exception of the organic matter which is slightly higher; the average value is equal to 8.64 ± 5.19. The content of nutrients can be considered as the low or medium (for instance, the potassium is only 73 ppm) as compared with other forests in the study area, except the content of phosphorus, which is considerably higher (21.8 ppm versus 1–6 ppm).