Effect of a new irrigation system using recycled water on stomatal behaviour, photosynthesis and nutrient uptake in olive trees (Olea europaea L.)

Abstract

SummaryTwo sources of water (clean water or recycled water) and two types of irrigation system [sub-surface leaky irrigation (SLI) or surface irrigation (SI)] were applied in a split-plot experimental design, with four replicates, to study the effects of water quality and irrigation system on the physiological behaviour and growth of olive trees (Olea europea L.) in a semi-arid region.The results showed that SLI affected not only the number of open stomata, stomatal length, rate of net photosynthesis (by 32%), leaf areas (by 21%), and stomatal conductance, but also leaf nitrogen and proline concentrations. Plants irrigated with recycled water had higher rates of photosynthesis (by 22%) and leaf areas (by 14%) compared to those given clean water. Recycled water increased the uptake of nitrogen (N) and magnesium (Mg2+) ions by 67.5% and 6.0%, respectively, which could result in higher chlorophyll concentrations, rates of photosynthesis and, eventually, enhanced plant growth. The results suggest that the use of recycled water in an SLI system was optimum for irrigating olive trees, and that SLI was more efficient than traditional SI for olive groves in a semi-arid climate.