PROPERTIES AND CLASSIFICATION OF SOILS OF THE SWEDISH LONG-TERM FERTILITY EXPERIMENTS .3. SITES AT VASTRABY AND S UGGLARP

摘要

The Vastraby soil (Kattarp) was classified as a fine, mixed, mesic Typic Endoaquoll according to the Soil Taxonomy and as a Haplic Phaeozem according to the FAO revised legend. The soil profile consisted of a very dark grey-coloured Ap-horizon and a subsoil with a calcium carbonate content (0.4-21.4%) increasing with depth. The textural composition of the Vastraby profile was found to be 24% clay, 20% silt (2-60 mu m) and 56% sand in the Ap-horizon and 55% clay, 42% silt (2-60 mu m) and 3% sand in the subsoil, on average. The bulk density was highest between 30 and 50 cm depth (1.70 kg dm(-3)), average values for 0-30 cm depth and the subsoil were 1.59 kg dm(-3) and 1.40 kg dm(-3), respectively. Assuming a groundwater table of 1 m, the amount of plant available water was 167 mm. Amounts of carbon and nitrogen in the Ap-horizon of the Vastraby soil were 73 t C ha(-1) and 5.6 t N ha(-1), respectively, while the subsoil to a depth of 1 m contained 42 t C ha(-1) and 5.4 t N ha(-1). The cation exchange capacity (CEC) amounted to 13.7 meg 100 g(-1) in the Ap-horizon. The main clay mineral found was illite, amounting to 35%. Kaolinite amounted to 7% of the clay fraction, chlorite to 1-2% and vermiculite increased from 3 to 15% with depth. Mixed layer minerals of illite/smectite type were present at 18% in the Ap-horizon and at 6% in the subsoil.