Defining Optimal Strength of the Nutrient Solution for Soilless Cultivation of Saffron in the Mediterranean

Abstract

Saffron is traditionally cultivated in soil as a semi-perennial crop, although the feasibility of crop production is today constrained in Europe due to both agronomic and socioeconomic factors. Accordingly, interest has been increasing concerning its possible cultivation within protected environments through adoption of soilless cultivation technologies. The aim of the present study was to optimize nutrient solution features in the soilless cultivation of saffron corms. The trial was conducted in a greenhouse at Almeria University. Saffron was grown in 15-L pots filled with perlite. Three fertigation treatments were used, obtained by a linear increase of all nutrients of one standard in order to reach an electrical conductivity (EC) of 2.0 (control, EC2.0), 2.5 (EC2.5) and 3.0 (EC3.0) dS·m−1. Measurements included determinations of shoot length, corm yield, as well as nutrient uptake from the nutrient solution and concentrations within plant tissues. The nutrient solution with the highest EC (EC3.0) allowed obtaining three to five times more corms above 25-mm diameter. The increasing EC had a significant effect on the increase of macronutrient uptake, except for NO3− and NH4+ and resulted in a general increase of nutrient concentrations in tissues, such as corms and roots. Both macronutrient uptake and accumulation in plant tissues were highest under EC3.0. Nutrient uptake was significantly correlated with production of larger corms due to higher horizontal diameter.