Optimizing saffron (Crocus sativus) yield and quality through nutrient inputs and timing

The study was conducted from 2016 to 2020 and involved the application of eight fertilizer treatments. These treatments included single doses of 45 g m −2 of NPK 15–15-15 applied in autumn (A), winter (W), and spring (S); double doses of 90 g m −2 split evenly in autumn-winter (AW), autumn-spring (AS), and winter-spring (WS); and a triple dose of 135 g m −2 split evenly in autumn-winter-spring (AWS). A control group (C) received no fertilizer. The triple dose treatment yielded the most effective results in terms of saffron yield parameters. The number of flowers m −2 in AWS increased from 73.0 in 2017 to 547.6 in 2020, while control exhibited a slight increase from 32.0 in 2017 to 68.1 in 2020. Double dose treatments were also effective in enhancing yield parameters compared to the control. A single dose treatment applied in spring (S) had a limited impact compared to A and W treatments. Over five years, S, A, and W treatments exhibited an average flower number of 97.9 m −2 , 181.1 m −2 , and 136.1 m −2 respectively . The qualitative characteristics of saffron, including color (crocin), taste (picrocrocin), and aroma (safranal), were not significantly influenced by fertilization treatments. These attributes remained within the natural limits defined by ISO-3632.