Document Type : Original Article
Authors
1 1- Innovation project leader, Research and development department, Tessenderlo Kerley International, Belgium
2 2- Associate Professor, Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad
3 3- PhD student in Agroecolology, Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad
4 4- Master student in Horticulture, Department of Horticulture Science, Faculty of Agriculture, University of Mohaghegh Ardabili
Abstract
Introduction: Saffron (Crocus sativus L.) is one of the oldest plants in Iran and plays a significant role in improving the economic and social status of farmers. However, its production mostly relies on indigenous knowledge (Koocheki et al., 2009), and its yield is considerably lower compared to other producing countries (Koocheki et al., 2012). According to available statistics, there is at least a 70% yield gap in saffron crop in Iran (Koocheki, 2018).
Nutrients, especially towards the end of the growing season (Bertheloot et al., 2008; Dordas, 2009), play a crucial role in improving flower yield of saffron. Nutrient availability is considered as one of the most effective factors in promoting the growth of daughter corms (Koocheki et al., 2014; Koocheki & Seyyedi, 2015). This study aimed to assess the impact of potassium (as KTS®) and calcium (as CaTs®) thiosulphates on soil chemical properties, as well as the quantitative yield of saffron such as leaves, daughter corms, and flower of saffron under on-farm conditions.
Materials and Methods: This experiment was conducted based on a randomized complete block design with three replications under on-farm management in Zaveh, Torbat-e Heydariyeh county, Khorasan-e Razavi, Iran during the 2019-2020 and 2020-2021 growing seasons. The treatments included: T1: conventional on-farm management as control, T2: T1+application of 40 liters of KTS per ha three times, T3: T1+application of 20 liters of KTS per ha three times, T4: T1+application of 50 liters of CaTs per ha four times, T5: T1+application of 100 liters of CaTs per ha two times and T6: T1+application of 67 liters of CaTs per ha three times. KTS and CaTs were applied as soil treatment with irrigation. The study assessed several traits, including flower yield indices (such as flower numbers, fresh weight of flower, dried weight of stigma per m2 and stigma length), leaf growth (including leaf length and leaf dried weight), daughter corm yield (such as number of daughter corms, dried weight of daughter corms per m2, daughter corm diameter and mean weight of daughter corm), and soil properties (including pH, EC, total N, available P, and available K).
Results and Discussion: The results showed that the application of potassium fertilizers (KTS) and calcium (CaTs) had a significant effect on various indices related to flowers, and leaves, as well as on the soil chemical properties. T6 had the highest and T5 had the lowest stigma dry weights. Similarly, the highest and lowest number of daughter corms were obtained in T6 and T5 treatments, respectively. The highest leaf length and dry weight of leaves were observed in T6. The highest and lowest of daughter corm numbers (with 7950 and 1865 corms.m-2, respectively) and dried weight of daughter corms (equal to 24579 and 7859 g.m-2, respectively) were belonged to T6 and T5, respectively. Furthermore, the highest and the lowest levels of available potassium content in the soil were observed in the first stage for T4 and conventional management (with 625 and 254 mg.kg-1, respectively), respectively. The highest levels of this characteristic were observed in the second, third, fourth, and fifth stages for T3 (with 671, 697, 723, and 758 mg.kg-1, respectively), while the lowest levels were associated with conventional agricultural management (equal to 233, 217, 201, and 189 mg.kg-1, respectively).
Conclusion: Based on the results, T6 was identified as the best treatment for saffron farms in Zaveh. The study suggests that paying close attention to the balance of nutrients and chemical parameters of soil can significantly improve crop yield and soil fertility in saffron farms. The application of calcium and potassium thiosulfate fertilizers as soil amendments during the growth season resulted in a decrease in pH and available phosphorus content, as well as an increase in electrical conductivity, total nitrogen, and available potassium content in the soil. Therefore, the use of KTS and CaTs fertilizers as thiosulphate are recommended for achieving sustainable production, particularly in arid and semi-arid areas where potassium and calcium are crucial for saffron cultivation. To determine the impact of these fertilizers on the intended soil properties, it is advisable to conduct further and more extensive studies on their application in saffron farms.
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