The paper reports a study on the influence of irrigation method on water relations and growth of pot geranium (Pelargonium peltatum L.) plants cultivated in a peat-perlite mixture. Two parallel experiments were conducted using difference sources of water for the preparation of nutrient solution: groundwater containing 10 mmol L-1 NaCl or rainwater with less than 0.5 mmol L-1 NaCl. In each experiment, six treatments, which derived from the factorial combination of three irrigation systems (open- or closed-loop drip irrigation, trough technique with recycling drain water) and two scheduling methods (timer vs. tensiometer with a water tension threshold of 50 hPa), were compared. In closed systems, the mixing tank was completely emptied whenever the EC of recycling nutrient solution exceeded 3.50 dS m-1. In both experiments, the use of tensiometer reduced significantly the water runoff in free-drain drip irrigation compared to the timer-based scheduling. The use of rainwater did not affect plant water uptake, which averaged 81.2 L m-2. In all closed systems the recycling water was never flushed out and then total water use corresponded to plant water requirement. In open drip irrigation, a huge runoff was produced, although it was substantially reduced by the use of tensiometer. When groundwater was used, in closed drip irrigation the nutrient solution had to be discharged in one (tensiometer) or two occasions (timer), since its EC had reached the pre-set ceiling value; total runoff was 12.5 or 25 L m-2 , respectively. No important effects of irrigation system and scheduling method on plant growth characteristics was observed in the experiment carried out using rainwater. By contrast, the use of saline water resulted in a significant reduction of all growth parameters in closed-loop drip irrigation. Some reduction of plant fresh and dry weight, and leaf area and number of stems per plant was observed for subirrigation treatment with tensiometer-based control. The influence of irrigation technique and water quality on post-production plant performance was also investigated by simulating amateur cultivation in a patio with manual overhead irrigation. It was found that only the plants that had been subirrigated with saline water showed a rapid occurrence of leaf necrosis and abscission due to the solubilization of the salts accumulated during cultivation in the top layer of pot substrate.
The Influence of Irrigation Method on Pot Geranium (Pelargonium peltatum L.) Grown with Saline Water
P Battista;B Rapi;L Bacci
2009
Abstract
The paper reports a study on the influence of irrigation method on water relations and growth of pot geranium (Pelargonium peltatum L.) plants cultivated in a peat-perlite mixture. Two parallel experiments were conducted using difference sources of water for the preparation of nutrient solution: groundwater containing 10 mmol L-1 NaCl or rainwater with less than 0.5 mmol L-1 NaCl. In each experiment, six treatments, which derived from the factorial combination of three irrigation systems (open- or closed-loop drip irrigation, trough technique with recycling drain water) and two scheduling methods (timer vs. tensiometer with a water tension threshold of 50 hPa), were compared. In closed systems, the mixing tank was completely emptied whenever the EC of recycling nutrient solution exceeded 3.50 dS m-1. In both experiments, the use of tensiometer reduced significantly the water runoff in free-drain drip irrigation compared to the timer-based scheduling. The use of rainwater did not affect plant water uptake, which averaged 81.2 L m-2. In all closed systems the recycling water was never flushed out and then total water use corresponded to plant water requirement. In open drip irrigation, a huge runoff was produced, although it was substantially reduced by the use of tensiometer. When groundwater was used, in closed drip irrigation the nutrient solution had to be discharged in one (tensiometer) or two occasions (timer), since its EC had reached the pre-set ceiling value; total runoff was 12.5 or 25 L m-2 , respectively. No important effects of irrigation system and scheduling method on plant growth characteristics was observed in the experiment carried out using rainwater. By contrast, the use of saline water resulted in a significant reduction of all growth parameters in closed-loop drip irrigation. Some reduction of plant fresh and dry weight, and leaf area and number of stems per plant was observed for subirrigation treatment with tensiometer-based control. The influence of irrigation technique and water quality on post-production plant performance was also investigated by simulating amateur cultivation in a patio with manual overhead irrigation. It was found that only the plants that had been subirrigated with saline water showed a rapid occurrence of leaf necrosis and abscission due to the solubilization of the salts accumulated during cultivation in the top layer of pot substrate.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
