Optimizing Saffron (Crocus sativus) Yield and Quality through Nutrient Inputs and Timing: Insight from a Study in Lebanon

This study investigated the influence of nutrient inputs and their timing on saffron yield and quality. The study was conducted from 2016 to 2020 and involved the application of eight different fertilization treatments at various stages of saffron growth. These treatments included single doses in Autumn (A), Winter (W), and Spring (S); double doses in Winter-Spring (AW), Autumn-Spring (AS), and Winter-Spring (WS); and a triple dose in Autumn-Winter-Spring (AWS). A control group (C) received no fertilizer. A compound fertilizer with a 15-15-15 composition was applied across all treatments, with nitrogen (N) rates of 67.5 kg/ha for single doses (A, W, S), 135 kg/ha for double doses (AWF, ASF, WSF), and 202.5 kg/ha for the triple dose (AWSF). Similar rates were applied for phosphorus (P) and potassium (K). The findings demonstrated that fertilization generally enhanced saffron attributes. The triple dose treatment yielded the most effective results. The timing of fertilization also played a crucial role, as split applications during different growth stages led to higher production especially winter fertilization. However, spring fertilization had limited impact due to decreased plant activity and reduced nutrient absorption during that period. Although the yield increased, the qualitative aspects of saffron, including color (crocin), taste (picrocrocin), and aroma (safranal), were not significantly influenced by the fertilization treatments. Nevertheless, these attributes remained within the natural limits defined by ISO-3632, indicating that fertilization practices did not compromise saffron quality. Our study highlights the significance of nutrient inputs and their timing in optimizing saffron yield. It provides valuable insights for developing efficient fertilization programs to enhance saffron production while preserving its quality characteristics.