Effects of Leaf Spraying with Different Concentrations of Aa40 and Humus-S Biofertilizers on Flower Yield and Corm Yield of Saffron (Crocus sativus L.)

IntroductionSaffron (Crocus sativa L.) is the most expensive spice. Better farming and improvement agronomic operations are process of production for qualitative and quantitative improvement of the product as a result of research, education and promotion of new methods of planting, growing and harvesting product. Application of new techniques to saffron could help to compete in global markets with saffron produced in other countries. The researches that have been conducted about the influence of nutrients on saffron quality and quantity, have shown that flower yield and stigma yield stigma were affected by nutrient positively. In this paper we aimed to study the effects of two types of bio-fertilizers (Humus-s and Aa40) and different concentrations on the flower yield, daughter corm yield, stigma yield, leaf weight and leaf length of saffron under the climatic conditions of Kardeh, Iran.Materials and methodsIn order to study the effects of two types of bio-fertilizers and their concentrations on flower yield, stigma yield and daughter corm yield of saffron, a field experiment was performed in a 4-year field at Kardeh dam during 2016-2017. This experiment was carried out as two-factorial based on a randomized complete block design with three replications. The first factor comprised of two types of bio-fertilizers (such as Humus-s and Aa40) and the second factor included concentrations of 0, 1, 1.5, 2 and 2.5 per 1000 as leaf spraying in two times. Fresh weight of flower, dry weight of stigma, fresh weight of stigma, dry weight of flower without stigma, fresh weight of flower without stigma, fresh weight of leaf, dry weight of leaf, weight of daughter corms, number of daughter corms, fresh weight of stigma, fresh weight of flower without stigma, flower number, number of daughter corm in different weight groups such as 0.1-5, 5.1-10, 10.1-15, and >15 g and leaf length of saffron were studied traits. The treatments were run as an analysis of variance (ANOVA) to determine if significant differences existed among treatments means. Multiple comparison tests were conducted for significant effects using the Duncan’s test.Results and discussionThe results indicated that the fertilizers had not significantly effect on none of studied traits. The effect of different concentrations was significant on fresh weight of flower, dry weight of stigma, dry weight of flower without stigma, fresh weight of leaf, weight of daughter corms, fresh weight of stigma, fresh weight of flower without stigma, number of flower, number of daughter corms with >15 g weight and leaf length of saffron. The interaction effect between fertilizer type and concentrations had significantly effect on fresh weight of leaf. The highest dry weight of stigma and dry weight of daughter corms were observed in 2.5 per 1000 with 1239.98 and 4955 g.m-2, respectively. The lowest for the traits were related to control with 930.56 and 4085 g.m-2, respectively. The maximum and the minimum number of daughter corms were obtained in 2 per 1000 and control with 415 and 380.33 No.m-2, respectively.ConclusionIt seems that foliar spraying had positive effects on growth and yield of flower, stigma and daughter corm of saffron.  So, it is recommended that foliar spraying is used in the production of saffron and besides reducing use of other common fertilizers, other benefits of this fertilizers are enjoyed. Foliar spraying in order to accurate control of releasing nutrients can be an effective step towards achieving sustainable agriculture and compatible with the environment. Using foliar spraying as a substitute for conventional iron chelate fertilizers, element of iron fertilizer is released gradually and in a controlled way and as a result provides nutrient to plant more effectively.