Use of Azolla as a growing medium component in the nursery production of olive trees

Peat is used in olive-tree nurseries as a component in commercial growing media. Environmental and economic pressures are questioning the use of peat as a component of substrates. In order to remain competitive and to satisfy environmental concerns, it is necessary to identify and evaluate possible alternatives to peat. This study involves the use of Azolla filiculoides, as a growing media component in olive nurseries (Olea europaea L.) for containerized plants. Four treatments were established, based on the addition of increasing quantities of Azolla (0%, 25%, 50%, and 100 %). Were determined some physical and chemical properties of media, the growth, the physiological parameters and nutritional state of olive plants. The physical and chemical properties of the media were significantly affected by the Azolla content. Nursery-produced olive plants grown in substrates supplemented by 50 % Azolla displayed linear growth and the total biomass production greater than those of the control medium. The research indicated that Azolla might be suitable substrate component for olive plants grown in containers.