ASSESSMENT OF TWO SUBSTRATES FOR THE PRODUCTION OF POTTED BAY LAUREL IRRIGATED WITH SALINE RECLAIMED WASTEWATER

An experiment was carried out to assess the influence of two substrates (coco-nut fiber [CC] and urea formaldehyde foam [UF]) on the agronomical and physio-logical behavior of potted bay laurel (Laurus nobilis L.) irrigated with saline recycled wastewater (RW). Fresh water (FW) was used as a control. Roots and leaves grew differently in each growing medium. With FW the plants cultivated on UF had higher root growth than those cultivated in CC, while no significant differences were observed in root biomass under RW. The plants grown in UF decreased their leaf area by about 20% compared with those grown in CC regardless of water quality. Water consumption in UF was lower than in CC, while both the leaching fraction and the electrical conductivity (EC) of the leachate were higher in UF with the two types of water; in contrast, the pore EC in UF was lower than in CC. The plants cultivated in CC had a higher photosynthesis rate and higher stomatal conductance than in UF under FW; but under RW the photosynthesis rate was similar in the two substrates, while stomatal conductance was higher in UF. When RW was applied, the leaf Cl^-, Na⁺ and B³⁺ contents in CC were higher than in UF. Our findings indicate that growth and development response to RW was better in plants grown in CC than in UF. So, RW and UF, together, resulted in a fall in ornamental quality and therefore in the commercial value of the plants.