Phosphorus content and distribution and the activity of phosphatases in Arenosols in a forest affected by long-term exposure to the effects of the Anwil S.A. nitrogen works in Włocławek

This paper presents the results of research examining the soil content of total and available phosphorus (PE-R), taking into consideration the activity of alkaline and acid phosphatases. For this study, three soil profiles were sampled in Arenosols at a distance of 0.8, 2.0 and 2.5 km from a nitrogen fertiliser manufacturer, Anwil S.A. A control profile was taken from the Tuchola Forest. The soils’ reaction ranged from acidic to very acidic. The humus content in the surface horizons of the sampled profiles was average (1.26–2.61%). The lowest PE-R content was found in the profile taken closest (0.8 km – profile I) to the factory. The distribution index (DI) calculated for available phosphorus pointed towards moderate accumulation, whilst at the same time, the availability index (IM) confirmed low availability, especially in profile I. The activity of alkaline and acid phosphatases, which are the enzymes responsible for phosphorus transformation in the soil, varied depending on the distance from the nitrogen works. The inhibition of alkaline phosphomonoesterases and the stimulation of acid esterases, which were both connected to the examined soil reaction, were observed. The activity of phosphatases, as well as total and available phosphorus content, decreased steeply along the soil profiles. Furthermore, a significant correlation between organic carbon and the activity of alkaline and acid phosphatases (r = 0.94, p < 0.05 and r = 0.67, p < 0.05, respectively), as well as between the content of PE-R and the activity of alkaline phosphatase (r = 0.67, p < 0.05) were recorded. The results suggest the need for further research and monitoring of the Arenosols in the forest affected by the nitrogen works.

Przemysław Szmit