Abstract

This research was carried out on Galia melon plants grown in perlite in greenhouse at a density of 2 plants m(-2). The seeds of these plants were primed with two nitrogen forms (NO3- or NH4+) and NaCl at a concentration of 8 gr N l(-1) or 300 mM respectively, or not primed (Control). All seeds were germinated in a rhizotron and then sown in the nursery and treated with four fertigation solutions of differing levels of salinity. Two treatments were evaluated in which the Sodium Absorption Ratio (SAR) of the irrigation water was modified by the direct supply of cations (Ca2+ an Mg2+), and the indirect supply of K+ and anions (NO3-, HPO4- and SO4=) increasing the Electrical Conductivity (EC) of the fertigation solution. Four fertigation treatments were used (SAR 10 9, 7, 6 and EC 3, 4, 5, 6), thus modifying the ionic ratios of Na+/K+, Na+/Ca2+, Na+/Mg2+ and Cl-/NO3-. The fertigation solution with lower SAR and higher EC led to an increase in fruit production, lower average fruit weight, a greater number of fruits and a higher percentage of total soluble solids. These results suggest that the effect of salinity on crop production depends on both the amount of dissolved salts and the ionic ratios established at the level of the rhizosphere. This should be considered for designing alternative models for predicting the response of horticultural crops, such as melon, to increasing salinity.