Changes in the Activity of Phosphatase and the Content of Phosphorus in Salt-Affected Soils Grassland Habitat Natura 2000

The subject of this study was the humus horizons in the salt-affected soils of Natura 2000 (Ciechocinek, Poland). In the adequately prepared soil, there were determined: pH in CaCl2, total organic carbon (TOC), exchangeable cations (Ca2+, Mg2+, Na+, K+), salinity (EC1:5), the content of total (TP) and available phosphorus (AP), the activity of alkaline (AlP) and acid (AcP) phosphatases. TOC affected the degree of saturation of the sorption complex with basic cations, as confirmed by correlation analysis. In the analysed soil samples a series of quantitative cations of basic character is as follows: Ca2+>Na+>K+>Mg2+. Increased salinity has modified the qualitative and quantitative composition of the soil solution. Correlation analysis confirmed the significant relationship between the conduction of the electrolytic soil and the content of sodium and potassium cations. The highest value of EC1:5 was found in the soil sampled near the ditch (sites 12, 13, 16). According to PN-R-04023 (1996), this soil classifies as class V with a very low content of P available but the availability factor for phosphorus value ranged from 2.773 to 5.252% indicating that soil P was sufficient for plant growth in this habitat. Significant positive correlations were found between salinity, alkaline phosphatase and exchangeable K+, Na+. Significant negative correlations were found between EC1:5 with P available and the availability factor for this nutrient (AF). The positive significant correlations among soil alkaline phosphatase and some physicochemical properties suggested that salinization had effects on these variables. Alkaline phosphatase may be used as indicators of soil quality in salinized grassland habitat Natura 2000