Spatial and temporal variability of sulphate concentration in soils

The mobility of soil sulphate is high on agricultural sites with soil pH values of higher than 5 due to a low adsorption capacity. Under humid conditions, the variability of soil texture and hydrological soil properties resulted in a high fluctuation of soil sulphate content within space and time. Investigations into the spatial variability of soil sulphate produce a coefficient of variation of the soil sulphate content between 15 and 100% at different soil depths, with the highest variation present in the deeper soil layers. The results of the geostatistical analysis indicate that a sampling distance of not more than 25 m is required to determine spatially correlated values. No correlation between the sulphate content of the soil and the total S status of cereals was determined from grid sampling on two sites in northern Germany, indicating that soil analysis of sulphate was not an appropriate method for the prognosis of the sulphur nutritional status. The variability of the soil sulphate content in space and time was too high to show a relationship with the less variable plant tissue contents.