The effect of Hydropolymers on soil microbial activities in Mediterranean areas

Objectives. The aim of this study was to evaluate the effect of the hydropolymer TerraCottem on soil microbial activity by measuring soil respiration and leaching of mineral nitrogen. Materials and methods. The incubation experiment contained control variants with natural soil of Nerja area (South Spain, inside the Sierra Tejeda, Almijara and Alhama Natural Park, 36.7985173° N 3.8511693° W; WCGS84), variants with the addition of easy available nitrogen compounds (kg N ha-1), easy accessible carbon compounds (1% glucose solution) and a combinations of both. Within each variant, the recommended amount of control hydropolymers (1.5 kg/m 3) and a double dose of 3.0 kg/m 3 were compared. Results. Showed that respiration activity of the soil in this Mediterranean area was not eliminated by the lack of ready available nitrogen or carbon substrates. Furthermore, differences in CO 2 production between the variants containing different amounts of hydropolymers were not significant. A statistically significant difference in the CO 2 production was found in the first week compared to longer time periods. Conclusions. The mineral nitrogen leaching measurement showed that the biological activity of the studied is not affected by nitrogen dynamics which is balanced regardless of the amount of applied hydropolymer. On the other hand, leaching processes occurred when soil was doped only with nitrogen compounds or only carbonaceous, a problem that can appear after fertilizers applicatio