Influence of superabsorbent polymers on the chemical composition of strawberry (Fragaria × ananassa Duch.) and biological activity in the soil

By improving the air and water properties of soils, superabsorbent polymers can affect the increase and improvement of the quality of the yield of berry plants, including strawberries. Their presence in the soil has an influence on its biological activity as related to microorganisms. The aim of the research was to assess the influence of superabsorbent polymers added to the soil on the content of macroelements and sodium in the leaves and fruit of strawberry of the ‘Elsanta’ cultivar and changes in the number of soil bacteria, actinomycetes and fungi. The superabsorbent polymer (AgroHydroGel) was used in two doses: 1.8 and 3.6 g dm^-3 of soil. The content of phosphorus, potassium, calcium, magnesium and sodium was assessed using the ASA method, while the content of nitrogen and sulphur was assessed by the elemental analysis method (CHNS analyser). The number of microorganisms was assessed with a BacTrac analyser and the coefficient of microorganism development extent (SR) was also determined. AgroHydroGel increased the content of nitrogen and potassium in leaves and fruit but did not affect the content of phosphorus, sulphur and sodium. The addition of the superabsorbent at a dose of 3.6 g dm^-3 of soil reduced the magnesium content both in the leaves and fruit of the strawberry. AgroHydroGel decreased the content of calcium in the fruit. The use of AgroHydroGel contributed to the expansion of the K ion ratio to other ions, both in the leaves and fruits. We observed a significant increase in the amount of soil bacteria (1.8 g dm^-3 dose) and no significant influence on actinomycetes and fungi (irrespective of dose used).