EFFECTS OF SALINE WATER ON TOMATO UNDER SUBSURFACE DRIP IRRIGATION: NUTRITIONAL AND FOLIAR ASPECTS

A field experiment on the effects of drip irrigation (DI) and subsurface drip irrigation (SDI) with saline water (6.57 dS m(-1)) on three tomato cultivars (Lycopersicon esculentum Mill., cvs. Rio Tinto, Rio Grande and Nemador) was carried out with the purpose to quantify physiological responses. The aim was to improve irrigation water management under saline conditions of Tunisia. The trial was established in a silt-clayey soil with three regimes of irrigation: 100 %, 85 % and 70 % of crop water requirement. Results evidenced a significant difference between the two irrigation systems for the three cultivars. Growth parameters such as leaf area, chlorophyll content and mineral composition of leaves, petioles, stems and roots were affected significantly by the different treatments, particularly for Rio Tinto and Nemador, being Rio Grande the more adapted. The fruit was the organ less affected. Strong accumulation of Na+ and Cl-accompanied a reduction in Ca2+, K+, Mg2+ and P content in the case of DI. The distribution of these last necessary elements for plants nutrition under a strong accumulation of Na+ and Cl- depends on the cultivar and changes from one organ to another. SDI can be included as an effective option for tomato production in Tunisia.