Physiological responses to different irrigation regimes of shade trees grown in container

The aim of this work was to investigate the effects of two different irrigation regimes on growth and physiology of some widely used shade tree species grown in containers. Trees were irrigated with 1200 ml/day (normal irrigation, NI), according to the standard water volumes distributed in the nurseries, or 600 ml/day (reduced irrigation, RI). Among the species investigated, only Tilia cordata showed greater growth under normal irrigation if compared to reduced irrigation. The other species included in this experiment (Acer pseudoplatanus, A. platanoides, T. tomentosa, and T. platyphyllos) had no benefits from normal irrigation and, under reduced irrigation, showed no symptoms of water stress. Irrigation had no effect on leaf gas exchange of the species considered. Therefore, for these species, water consumption can be reduced by a half without affecting nursery stock quality. This study demonstrated that irrigation volumes usually distributed in nurseries are generally too high if compared to the real needs of the crops and that they can be reduced without decreasing product quality. This will lead to greater sustainability of nursery management practices and water savings.