Saffron Agronomy and Technology

Abstract The shift toward sustainable medicinal plant production underscores the importance of biological inputs. This study evaluated the effects of humic acid application, mycorrhizal inoculation, and two irrigation regimes on reproductive growth and quality of saffron (Crocus sativus L.). The experiment was conducted as a split-split plot based on a randomized complete block design (RCBD) with three replications, where irrigation intervals (20 and 40 days) were the main plot, humic acid (0 and 5 kg.ha⁻¹) was the sub-plot, and mycorrhizal inoculation (noninoculated, Glomus mossea, and G. intraradices) was the sub-sub plot. The studied traits were the number of flowers, flowering rate, flower yield, petal yield, style yield, and stigma yield, as well as stigma quality parameters (crocin, picrocrocin, and safranal content). Results indicated that the triple interaction of experimental factors was significant on all studied traits. The shortest irrigation interval (20 days) combined with humic acid application and G. mossea inoculation significantly increased fresh flower yield (79.63 g.m⁻²), dry stigma yield (0.88 g.m⁻²), style yield (0.22 g.m²), and petal yield (9.88 g.m ²). Crocin content was highest (274.5, absorbance of 1% aqueous solution at 440 nm) under 40-day irrigation intervals with humic acid and G. mossea inoculation, while safranal (35.80, absorbance at 330 nm) and picrocrocin (124.5, absorbance at 257 nm) improved under 20-day irrigation intervals with humic acid and G. mossea. Conversely, extended irrigation intervals (40 days) without humic acid and without mycorrhizal inoculation resulted in the lowest crocin and safranal content. Overall, the findings demonstrate that combining humic acid with G. mossea inoculation under frequent irrigation optimizes both the quantity and quality of saffron. It was concluded that although the use of organic inputs is beneficial, the results of their single application may differ from those of their combined application. On the other hand, the interaction among two or more of these inputs can also vary depending on conditions, including water availability and the type of mycorrhizal species.

Abstract This study aimed to explore the agronomic and economic implications of intercropping cumin and saffron in the Ghohestan region of South Khorasan province at a private research farm, under the supervision of the faculty of agriculture, University of Birjand, during the 2022-2023 period. To assess saffron's performance when intercropped with cumin, an experiment was set up based on a randomized complete block design with three replications in a uniform three-year-old saffron field. The experimental treatments involved different densities of cumin cultivation in the saffron field, including 0, 30, 60, and 120 plants per square meter (0, 25, 50, and 100% of its optimal density, respectively). The findings revealed that the LER index exceeded one in all treatment groups. The highest saffron stigma yield, recorded at 0.41 kg/ha, was achieved with an intercropping density of 60 cumin plants per square meter. The highest LER values were 1.94 and 1.92, obtained in the treatments with 30 and 60 cumin plants per square meter, respectively. Additionally, the Relative Value Total (RVT) was above one across all intercropping ratios. The greatest Intercropping Advantage index (IA), recorded at 0.074, was also achieved with the 60 plants per square meter cumin treatment. Consequently, increasing the cumin planting density in saffron fields, particularly at 60 plants per square meter, did not significantly affect saffron yield, leading to a recommendation for farmers in this region to adopt this practice for improved land use and economic benefit.

Abstract Evaluating the allocation trend of photoassimilates during the saffron growing season can lead to the identification of the key periods of plant growth. It is possible to improve the growth of the corm and ultimately increase the flowering of saffron by applying agricultural management according to the growth period. In this research, the allocation of photoassimilates between different organs of saffron under the influence of the mother corm weight (less than 4, 4-8, and 8-12 g) and the integrated and time-scheduled application of inputs (low-input and high-input), were investigated in a factorial layout based on a randomized complete block design with three replications. The maximum root weight was gained around 20th January (70 days after the first autumn irrigation) and the maximum leaf weight was observed on 29th February, and then it decreased, but after this date, the growth rate of the corm increased and reached its maximum value in the last month of the growing season. In all treatments, most of the mother corm reserves were consumed in the first 100 days after the first autumn irrigation, which coincides with mid-January. The production of replacement corms and their total weight accelerated 140 days after the first autumn irrigation, and its maximum amount (655 No. and 4148 g.m^-2, respectively) was obtained at the end of the growing season in the conditions of planting of big corms + high-input system. The highest mean weight of replacement corms (7.8 g) at the end of the growing season was obtained through planting of large mother corms + low-input system, while by planting small mother corms, the high input system increased the mean replacement corm weight. In all treatments, the highest corm growth rate was observed in the last month of the growing season (approximately 170 days after the first autumn irrigation). The total plant weight was strongly influenced by the weight of the mother corms, with no significant differences observed between the two input application levels. The highest crop growth rate (CGR) occurred in the final month of plant growth, reaching a maximum of 74.3 g.m⁻² day⁻¹ under the combination of large corm planting and a high-input system. The plant's relative growth rate (RGR) increased during the time intervals of 100–140 and 180–200 days after the first autumn irrigation. There was no significant difference between the treatments in terms of the duration of the active period of corm filling, and it was about 45 days. At the end of the growing season, the highest and lowest levels of photoassimilate remobilization (reallocation) from leaves to replacement corms (1016 kg.ha⁻¹ and 220 kg.ha⁻¹, respectively) were observed with the planting of large corms combined with a high-input system and small corms combined with a high-input system. The maximum remobilization efficiency (56.2%) was achieved by planting 4–8 g mother corms and using the high-input system. According to the results of this study, the final month of saffron growth was identified as the most critical period for the corm growth rate.

Abstract The storage conditions of saffron mother corms during the summer dormancy period, including natural and pseudo-dormancy stages, can probably affect the vegetative growth and the production of replacement corms (RC), which has not received enough attention in previous scientific studies. This experiment was carried out as a complete randomized block design with seven treatments and three replicates during the 2019 growing season in Qaen, Iran. Experimental treatments were three types of corm storage inside the soil [corm planting on 5th June (A) with natural soil temperature as control, A + summer irrigation on 5^th August, and A + mulch application obtained from wheat residues at the rate of 8 ton.ha^-1)] and four types of corm storage outside the soil [corm storage at room (ambient temperature) for three months started from 5^th June + corm planting on 5^th September (B), corm storage in constant temperature (25 ^oC and relative humidity of ~40 %) in incubator for three months + B, three months corm storage at variable temperature in incubator (one month in 20, 25 and 20 ^oC) + B and corm storage in room temperature (up to 5^th August) and incubator (up to 5^th September) + B. The studied traits were the length, number, and weight of leaves, the number and weight of the total RC, the weight of the main RC, the average weight of RCs, and the number and yield of RCs in different weight groups. The results showed that mulch application caused the highest length and number of leaves (35 cm and 9 No per plant, respectively). Incubation of corms at variable temperatures led to a significant increase in the total weight of RC. In contrast,  incubation at constant temperature had most significant effect on the number of RC (2022 corms per m²). The highest and the lowest mean weights of RC were obtained in the mulch application (7.23 g) and incubation at constant temperature (2.22 g), respectively. Plant residue treatment (mulch) decreased the number of small RC (less than 6 g) and increased the number of RC in the weight groups of 9-12 and 12-15 g. Incubation of mother corms at variable temperatures led to an increase in the number and yield of RC weighing more than 15 g. Overall, the treatments of plant residue consumption and storage of mother corms at incubator with variable temperatures, in which 66% and 61% of the RC yield was in groups weighing more than 9 g, respectively, were the best experimental treatments in terms of improving the growth of RC.

Abstract Recognizing the potential role of seaweed in improving saffron yield and the utilization of micronutrient elements like Ca, Mg, Fe, and Mn to enhance stigma yield, an experiment was conducted. The study investigated the impact of foliar spraying of seaweed extract and selected nutritional elements on saffron's quantitative and qualitative traits of saffron.This research was conducted, as factorial based on a randomized complete block design (RCBD) with four replications during 2021-2022 in Neishabur, Iran. The first factor consisted of seaweed extract (0 and 2 L.ha^-1) and the second factor consisted of foliar application of nutrients including no foliar application (as control), and the defender of some elements including iron (1.5 L.ha^-1 containing Fe, N, and amino acids), zinc, boron (1 L.ha^-1 containing B and amino acids), manganese (1.5 L.ha^-1 containing Mn, Zn and S), magnesium and calcium (2 L.ha^-1 containing Ca and N). The use of all nutrients compared to the control (no-nutrients) and the use of seaweed extract compared to no-seaweed application caused an increase in flower and stigma yields. Based on the interaction effects of the experimental factors, the highest number of flowers (68.8 No.m^-2) was obtained in the combined application of manganese and seaweed extract, the highest flower yield (33.5 g.m^-2) was gained with the combined application of seaweed and boron, and the highest dry stigma yield (0.48 g.m^-2) was obtained from the simultaneous application of magnesium and seaweed extract, which were 63.8, 16.7 and 17.0%, more than the control treatment (no-seaweed & No-nutrients), respectively. Without nutrient application, the utilization of seaweed extract resulted in a notable rise in the Picrocrocin content of the stigma by 15.9%, Crocin by 9.5%, and Safranal by 10.6% compared to the absence of seaweed application.Combined consumption of calcium with seaweed increased the content of Picrocrocin and Crocin, while simultaneous application of other nutrients with seaweed did not improve these indices. The highest and the lowest content of Safranal (37.7 and 32.35 absorption at 330 nm) were obtained from magnesium + no-seaweed and control (no-seaweed & no-nutrients) treatments, respectively. Overall, although all of the studied elements combined with seaweed extract improved stigma yield in order to increase stigma yield, application of Mg in combination to seaweed recommended and to enhance saffron quality using seaweed suggested.

Abstract This descriptive research was conducted as interviews using 125 questionnaires among the saffron farmers of Torbat-Heydariyeh, Iran, during 2020-2021. The aim of this study was to compare the most important agronomic operations related to saffron cultivation among three groups of farmers (ordinary, skilled and leading farmers), and to compare the methods used by the farmers with the recommendations of saffron researchers. The classification of farmers into the three mentioned groups was based on the stigma yield in relation to the field age. Before the research, the validity of the questionnaire was confirmed and its reliability was also determined using the test-retest method. The results showed that against 15% of leading farmers, none of the ordinary and skilled farmers had agricultural education. The average education of ordinary, skilled and leading farmers were 7.1, 7.5 and 10.9 years, respectively. Corm planting date of the highest number of ordinary and skilled farmers (46.2% and 35.7%, respectively) was in September, while for the leading farmers (37.5%) was in June. The average amounts of corm application by ordinary, skilled and leading farmers was 8.9, 8.9 and 10.5 ton ha-1, respectively, and the average amount recommended by researchers was 10.4 ton ha-1. All the saffron researchers recommended the corm row planting method, which is accordance with the 30, 43.1 and 44.4% procedures of ordinary, skilled and leading farmers, respectively. The minimum corm weight recommended by researchers was 8 g, which is applied by 18.7% of ordinary farmers, 25% of skilled farmers and 100% of leading farmers. Hand weeding was the most common method of weeds control among all farmers. Contrary to the recommendation of most researchers to remain saffron leaves as mulch, the leaves are mainly used as animal feed. The appropriate field age according to researcher’s recommendation was 5-6 years, while most of the farmers use the field for 7-8 years after each planting time. In general, the low level of knowledge, mass planting method (several corms in each planting point), planting of small mother corms, inappropriate planting date and long-term exploitation of the fields were the most important cases of improper field management, especially by ordinary farmers.

Abstract This research was conducted using questionnaires and the analysis of soil samples (the content of organic matter, nitrogen, phosphorus and potassium) obtained from saffron fields of Torbat-Heydariyeh, Iran, during 2020-2021. In this research, saffron irrigation and nutrition management methods among three farmer groups (progressive farmers, skilled farmers and ordinary farmers) were investigated and compared with the recommendations of saffron researchers. The classification of farmers in the mentioned three classes was based on the stigma yield in relation to the field age. The results showed that most of the progressive and skilled farmers used the combined nutrition management method (organic fertilizer + chemical fertilizer with frequency of about 65%), while the single application of chemical fertilizer was the most common method among ordinary farmers (47.5%). The mean amount of organic manure application for ordinary, skilled and progressive farmers was 5.0, 6.3 and 10.7 ton ha-1year-1, respectively (less than the amount of 19.2 tons recommended by researchers) and the mean amount of nitrogen application was 49.5, 56.5 and 87 kg ha-1 (compared with 93.3 kg recommended by researchers). The application of phosphorus and particularly potassium was not a common practice among all three groups’ farmers. The average content of organic matter in the fields was 0.68%, nitrogen 0.041%, phosphorus 16.1ppm and potassium 292 ppm, which indicates the poverty of soils in terms of organic matter and to some extent nitrogen. The foliar application of nutrients for the fields of ordinary, skilled and progressive farmers was 0.23, 0.65 and 1.00 times per year, respectively, and the average irrigation times was 3.2, 3.6, and 4.6 times per year, respectively, which is less than the recommended values by experts (2.55 and 5.8 times per year, respectively). Summer irrigation (44.4% of farmers) and sprinkle irrigation method (26.8% of farmers) were more common among progressive farmers. In general, the poverty of organic matter and lack of nitrogen in the soil, low foliar application of nutrients and lack of use of modern irrigation methods were among the most important reasons for the high gap yield of saffron fields.

Abstract Many activities during production, processing, trade and consumption of saffron (Crocus sativus L.) in Iran, are based on indigenous knowledge. Most share of saffron production in the country is obtained from small fields with family cooperation and using local environmental friendly inputs and technologies. Accordingly, a cosidarable part of saffron produced in Iran is close to the principles of organic farming, but in terms of rules and standards related to this production system, it is considered only as a quasi-organic product. Organic farming is a comprehensive production system that focuses on the quantitative and qualitative aspects of agricultural product during the production cycle (from farm to fork), as well as issues such as justice, social relations, soil health and the rights of all macro and mico organisms. Based on this definition and considering the principles and methods which are used for saffron production in Iranian agroecosystems, it is possible to create a targeted procrdure for its organic production, by perparation a standard. The preparation of this standard, while increasing farmers' incomes, will lead to maintaining and increasing Iran's share of the global market of this valuable medicinal plant. In this article, for all stages of saffron production cycle, using the results of scientific researches on saffron, as well as international, regional and national standards related to organic production, a set of general principles, suggestions (recommendations), requirements and notes are provided. The recommendations are mainly suitable for increasing the quantitative yield, while higher quality of saffron can be achieved by observing the proposed requirements. The guidelines proposed in this paper, besides improving the quantity and quality of the product, will also ensure the other objectives and rules related to organic farming. In the current proposed program, issues related to agronomy (corm production and selection, land selection and preparation, planting, soil nutrition, irrigation, control of biotic stresses, etc.), breeding, harvesting and post-harvest (flowers carrying and storage; separation, drying, grading, packing, labeling and storage of stigma) as well as processing and legal issues have been considered.

Abstract In order to investigate the impact bio fertilizer novafol and mother corm weight on leaves growth, chlorophyll content and flower and stigma yields of saffron (Crocus sativus L.), an experiment was done as randomized complete block design with three replications in the Agricultural Research Station, University of Birjand, during the growth season of 2016-17. Experimental factors were amino acid application (Novafol, containing 28% amino-acid. Applied as corm soaking + fertigation in three levels: 0, 2 and 4 L.ha-1) and mother corm weight (0.1-4, 4.1-8 and 8.1-12 g). The effect of bio-fertilizer novafol was significant on the flower number, flower yield, dry stigma yield and chlorophyll a content. The highest flower number (16.5 per m-2), flower yield (5.63 g m-2), dry stigma yield (0.108 g m-2) and chlorophyll a content (1.09 mg. g-1 FW) were obtained from 4 L.ha-1, while, the lowest flower number (14.22 per m-2), flower yield (4.55 g m-2), stigma yield (0.085 g. m-2) and chlorophyll a (0.97 mg. g-1 FW) were gained in control treatment, but, there was no significant difference between two levels (2 and 4 L.ha-1) novafol bio fertilizer. Corm weights aslo significantly affected all studied traits. The highest stigma length (25.1 mm), flower yield (10.4 g m2), leaf length (31.42 cm) and fresh and dry weight of leaves (0.29 and 0.083 g per plant, respectively) were obtained from big corms, but the lowest of them were obtained from small ones. Interaction effect of corm weight and novafol bio fertilizer was significant on chlorophyll b and total chlorophyll contents and number of leaves per plant. The highest chlorophyll b and total chlorophyll (1.77 and 2.95 mg. g-1 FW, respectively) and number of leaves (7.58 per plant) were obtained from 4 L.ha-1 of novafol bio fertilizer and big corm. Overall, application of novafol bio fertilizer (4 L.ha-1) improved the vegetative and reproductive growth parameters. Big corms planting also had an important role in increasing the growth and yield of saffron.

Abstract The combined effect of water and nutrient availability is one of the most important factors in corm growth and flowering of saffron. In addition, it seems that applying water in amounts more than conventional amounts in semi-arid areas can be more useful in saffron cultivation. Accordingly, the effects of irrigation regimes [two and four weeks intervals equal to application of 3600 (conventional irrigation treatment) and 7200 m³.ha^-1 (extensive-irrigation treatment) during saffron growth], as well as organic (30 ton.ha^-1 cow manure based on soil and manure analysis results) and chemical fertilizers (220, 150 and 100 kg.ha^-1 urea, super-phosphate and potassium sulfate, respectively) with a control treatment (no-fertilizer) are studied on some physiological growth indices, corm production and flowering of saffron in this experiment. The experiment was conducted as factorial based on a randomized completely block design with three replications in Sarayan county, Iran, during 2014-2016. Vegetative growth indices were studied during the first growth cycle, while flowering indices were measured during the second growth season. Total biomass has an increasing trend during saffron growth cycle in all treatments. This index was higher in cow manure treatment in both levels of water availability, during the last two growth months. Crop growth rate (CGR) was slow (below 3.9 g.m^-2.day^-1), rapid (3.9-12 g.m^-2.day^-1) and intermediate (5.5 g.m^-2.day^-1) in the early (the first 90 days of growth), middle (90-150 days after growth) and late (150-180 days of growth) growth periods. The highest CGR (12 g.m^-2.day^-1) was obtained in cow manure treatment and 145 days after the first autumnal irrigation. In all treatments, leaf weight ratio (leaf to total plant weight ratio) has a decreasing trend from two months after the first irrigation until the end of the growth cycle and it is slightly higher in fertilization treatments. Cow manure application increased the corm production and total corms weight per plant by 15 and 13%, respectively, compared with the control treatment. The highest mean weight of replacement corms (6.4 g) was shown in combined treatment of cow manure and two weeks' irrigation intervals. The highest values of flower number (98 flower per m²), flower yield (24.3 g.m^-2), style yield (0.56 g.m^-2) and dry petal yield (3.7 g.m^-2) were obtained in plants that had been treated with cow manure and received water in intervals of 4 weeks. In cow manure fertilizer and control treatments, the highest flower and stigma yield were obtained in irrigation intervals of 4 weeks, while in chemical fertilizer treatment, the highest flower and stigma yield were obtained in 2 week irrigation intervals. Therefore, it seems that application of cow manure combined with consumption of 3600 m³.ha^-1 is suitable during the first growth cycle of saffron during which corm density and transpiration area are low.

Abstract Saffron that is an important medicinal plant of Iran is influenced by several environmental stresses. Therefore, the consumption of appropriate hormonal and nutritional compounds can reduce the negative impacts of stresses on it and improve the growth and yield of the plant. For this purposes, an experiment was carried out based on a Randomized Complete Block Design with four replications to study the effect of Salicylic acid (0, 0.5, 1 and 2 mM) and Potassium Nitrate (0, 250,500 and 1000 ml.g^-1), in the research field station of the College of Agriculture, the University of Birjand, Iran, in the growing season of 2015. The indices evaluated included flower and corolla fresh weight, stigma weight and length, leaf length, corm and cormel weights and diameter, chlorophyll florescence parameters and total chlorophyll content. The results showed that the highest amounts of Fv, Fv/Fm, F'v/F'm (117, 0.27 and 0.44, respectively), total chlorophyll (0.85 µg.g fresh weight), flower and corolla fresh weight (36.9 and 32.1 g.m^-2, respectively), stigma weight (4.2 g.m^-2) and length (29.6 mm) and leaf length (37.7 cm) were obtained at 2 mM level of salicylic acid, while the highest F'm was recorded at 0.5 mM salicylic acid. In addition, pretreatment with 1000 mg.l^-1 potassium nitrate increased the amounts of cormel weight and diameter by 30% and 19% compared with the control, respectively. Generally, the results of this experiment indicated an enhancement in saffron growth and yield, affected by corms soaking in salicylic acid and potassium nitrate.

Abstract The use of corms with appropriate weight is one of the main factors in the flowering of saffron. Thus, the impacts of six organic (OS) and conventional (CS) production systems on the growth of saffron replacement corms was studied during one growth cycle from October 2015 up to May 2016 in this experiment. The experiment was conducted based on a randomized complete block design with three replications and six treatments including low, medium and high input organic systems as well as low, medium and high input conventional systems. A transition period of 24 months was considered in the chosen field before corm planting. Based on the results of an analysis of variance, the effect of experimental treatments was significant on the growth properties of most replacement corms (RC). The results of means comparison revealed that the differences within each organic or conventional system were insignificant but they were found to be considerable between the two OS and CS production systems. Total RC weight per clone and the number of flowering buds per RC in the OS production system were on the average 40% more than that of the CS production system. The amount of mean RC weight for OS and CS was 4.75 and 2.54g, respectively. The percent of RC with weight of less than 5g in the CS production system was higher than that of the OS production system (70 vs. 84%), while the percent of RC in 5-10g (13 vs. 14.5%) and more than 10g (3 vs. 15.7%) categories in the OS production system were more than that of the CS production system. The mean value of flowering buds had a significant correlation with the total RC weights per clone (+0.58^**), mean RC weight (+0.64^**), number of small RC (-0.57^**) and number of large corm per clone (+0.61^**). In addition, there was a significant correlation between the mean RC weight with the number of RC per clone (-0.55^**), the RC weight per clone (+0.73^**), the number of small RC (-0.89^**) and the number of large RC per clone (+0.81^**). Overall, the employment of OS had a significant positive effect on the growth of saffron replacement corms especially on mean corm weight and the number of flowering buds.

Abstract Selection of suitable mother corms is an important factor for achieving optimum yield in saffron. In order to investigate the effect of some agronomic factors on the growth of replacement corms of saffron, an experiment was done at the Faculty of Agriculture, the Ferdowsi University of Mashhad, Iran during 2009-2011. The experimental treatments  consisted of planting on the following dates (22 May, 22 July and 22 September, 2009), irrigation management (Irrigation and no irrigation after each planting date and repeating them in the second year in late spring, summer and early autumn  irrigations) and companion crops [Persian clover (Trifolium resupinatum), Bitter vetch (Vicia ervilia) (Lathyrus sativus) and control), that were arranged in a split-split plot experiment based on a randomized complete block design with 3 replications. Sampling of replacement corms was done after the second growth cycle of saffron in May, 2011. The results showed that with delay in corm planting from May to September, the number of replacement corms and percentage of corms with contractile root increased by 25 and 33%, respectively. However, the amounts of total weight of replacement corms per clone, mean number of flowering buds per corm, mean number of total buds per corm, mean weight and mean diameter of replacement corms planted in July were 21, 70, 40, 32 and 37% higher than those planted in September, respectively. Irrigation increased the amount of contractile roots and number of replacement corms per clone (12%), but decreased the amount of mean number of flowering buds (19%), mean number of total buds (11%) and mean weight (19%) and diameter (8%) of replacement corms. Moreover, application of companion crops had a partially positive impact on the indices of growth of replacement corms of saffron such as follows: the total weight of replacement of corms per clone (8%), corms to scales weight ratio (14%), number of flowering buds (10%) and mean weight of replacement corm (10%). Overall, mother corm planting during real dormancy, no irrigation after planting and during summer as well as application of associated crops have a positive effect on the mean weight of replacement corms as the main important factor in saffron flowering.