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| Authors: | A. Hamdy, W. Chouaib, G. Pacucci |
| Keywords: | inert substrate, perlite, pozzolana, sand, yield, hydroponics |
Abstract:
Cultivation of crops in soilless substrates is a practice gaining great interest internationally nowadays, especially under greenhouse conditions.
Moreover, in the arid and semi-arid regions of Mediterranean area, due to the shortage of freshwater, more attention has been paid to the use of low quality waters: saline and treated waste.
This work investigates the eggplant variety (Galine F1) response to saline irrigation practice in soilless culture.
Three inert substrates: sand, pozzolana and perlite, were utilized, in the absence and with the presence of soil conditioner (SC). Saline water with electrical conductivity of around 6.0 dS/m was used for irrigation.
A split-plot experiment with four replications was carried out under controlled conditions in greenhouse.
The soil conditioner was mixed with the inert substrates up to a depth of 9 cm at a ratio of 15% by weight.
Irrigation was managed by a computerized system and was practised with sea water mixed with freshwater and nutrient solution to reach a final EC value of 6 dS/m.
The average water consumption of eggplants was about 2900 m3 ha-1, and the yield water use efficiency (YWUE) of 23.5 g L-1. The greater improvement of YWUE of 28% with SC was observed for pozzolana substrate while the increment for perlite and sand was lower: 14 and 8% respectively.
Higher yields were obtained on perlite (73.2 t ha-1) followed by sand (64.6 t ha-1) and pozzolana (55.1 t ha-1). The presence of SC in the inert substrates improved (+20%) the yield only on pozzolana.
For all the investigated substrates, under saline irrigation, accumulated salts did not exceed the 4 dS/m, particularly at flowering and fruit setting growth stages.
Furthermore, monitoring the salt accumulation in the substrates during the cropping period is crucial and leaching should be practiced if salts exceed 4 dS/m.
The results confirmed that saline irrigation practice could be successfully applied for eggplants in soilless culture.
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