Abstract
The aim of this study, conducted during the 1997-2001 period in the Olsztyn Lakeland, was to determine the effect of soil type and land use in the catchment areas of small ponds, on the concentrations of nitrogen and phosphorus compounds, as well as calcium and potassium, in water. The concentrations of all the nutrients (except for nitrite ions) in the water of small ponds were found to be significantly correlated with the soil type dominating in the catchment area. The domination of loamy sands in the catchment areas of small ponds caused an increase in the concentrations of nitrates, phosphorus and potassium, while the domination of light silty loam caused an increase the calcium content of the water. The highest and lowest concentrations of phosphorus compounds and potassium were recorded in water from small ponds located in agricultural (arable land - AL, fallow - FA) and afforested catchments, respectively.