Eggplant production in soilless culture under saline irrigation practices and soil conditioner application.

摘要

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 investigated the aubergine cultivar (Galine F1) response to saline irrigation practice in soilless culture. Three inert substrates, i.e. sand, pozzolana [volcanic ash] and perlite, were utilized, in the absence and 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 4 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 aubergines was approximately 2900 m3 ha-1, and the yield water use efficiency (YWUE) was 23.5 g litre-1. The greater improvement of YWUE of 28% with SC was observed for pozzolana substrate while the increment for perlite and sand was lower at 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 aubergines in soilless culture.