Influence of the last irrigation cut-off time and various fertilizer resources on corm characteristics of saffron

In order to evaluate the effect of last irrigation cut-off time and various fertilizer resources on corm of saffron (Crocus sativus L.), an experiment was conducted in a split-plot arranged as a randomized complete block design with three replications and 18 treatments in a four year research farm of Jihad ministry located in Lalezar village, Bardsir region, Kerman province, in 2015-2016. The experimental treatments were irrigation cut-off time  (conventional time  (5 May), 15 days before the conventional time (20 April) and 15 days after conventional time (20 May)) assigned to main plot, and nutritional resources (cow manure 40 t ha-1, hen manure15 t.ha-1, vermicompost 10 t.ha-1, humic acid 2 kg.ha-1, and chemical fertilizer containing 200 kg.ha-1 urea and 140 kg.ha-1 P and K) as subplot. The analysis of variance results showed that the effect of irrigation cut-off treatment was significant on corm fresh, dry weight and average weight (P≤0.05), but had no significant effect on the number of corm per area and number of buds per corm. The results showed that the delay in irrigation cut-off led to a significant decrease in traits. As such, the highest corm fresh (561.5 g.m-2) and dry (294.8 g.m-2) weight and average weight of the corm (4.9 gr) were found in earlier irrigation cut-off treatment (before the conventional time). The effect of fertilizer resources on all the studied traits was significant. All the fertilizer treatments with the exception of humic acid, resulted in a significant increase in corm weight compared to control treatment. Application of vermicompost led to the production of the highest number of corm in m-2 (137.1), the corm fresh weight (595.6 g.m-2), dry weight (341 g.m-2) and average weight (4.30 g). The highest number of buds in corm (3.83) was found in chemical fertilizer treatment. In general, the results showed that irrigation cut-off in April with the using vermicompost had the best conditions for producing saffron corm in the Bardsir region of Kerman.