Relationship between soil properties and phosphate saturation parameters a transect study in northern Belgium

Abstract

We investigated the relations between soil properties and the variability at field-scale of soil P sorption capacity (PSC) and degree of P saturation (DPS), and the relationship between DPS and P concentrations in soil solution. Soil samples of 0–30 cm, 30–60 cm and 60–90 cm depths were collected every 10 meters on a transect of a total length of 539 meters in the northeastern part of the province Antwerp, Belgium. Oxalate extractable iron, aluminium and phosphate content (Fe OX, Al OX, and P OX) were determined, and the PSC and DPS calculated. Phosphate concentrations measured in 100 mM KCl extracts of the soil samples of the 0–30 cm layer were closely related to the DPS of the samples. The spatial distribution of Fe OX, was rather homogeneous, except in the vicinity of a “discontinuity” such as a drainage ditch, where much higher Fe OX values were measured. The spatial variability of the Al OX parameter was closely related to the spatial variability of the amount of oxalate extractable carbon and total carbon, but this was not the case for Fe OX. Detailed textural information for the transect did not correlate to PSC parameters at this scale; pH KCL or pH H 2O showed little variability on the transect scale. Variograms of the PSC parameters were obtained for three separate data-sets: one for the total transect, one for the total transect but excluding ditch data, and for part of the transect situated within one field (the first 410 m of the total transect).