Effects of vermicompost and nitroxin on replacement corm characteristics and flower yield of saffron (Crocus sativus L.) in the second year

The effects of applications of vermicompost and nitroxin on corm characteristics and flower yield of saffron were evaluated under field conditions in the research farm of Birjand University, Iran, during the cropping year 2015-2016. Treatments were of four levels of vermicompost (0, 5, 10 and 15 t.ha^-1) and three levels of nitroxin (0, 5 and 10 L.ha^-1). This experiment was carried out as factorial based on randomized completely block design with three replications. The results showed that vermicompost improved the corm vegetative indices (total weight of corm, average fresh and dry weight of cormel and diameter of cormel). The highest total weight of corm was obtained in plants treated with 15 t.ha^-1 vermicompost. Also results showed that vermicompost improved the saffron flower characteristics (flower number and fresh total yield, flower length, stigma fresh and dry yield) in second year of study. The highest stigma fresh (1.63 g.m^-2) and dry (0.41 g.m^-2) yield were obtained in plants treated with 10 t.ha^-1 vermicompost, while the lowest values (0.77 and 0.21 g.m^-2) were recorded in the control. Application of different levels of nitroxin has a positive effect on flower number and fresh total yield, stigma dry yield in the second year of the experiment. The highest stigma dry yield was observed in 10 L.ha^-1 nitroxin (0.36 g.m^-2), while the lowest value was recorded in control (0.24 g.m^-2).  Application of different levels of vermicompost and nitroxin had a positive effect on the total weight of corm, average flower length and stigma fresh yield. Thus, the results showed that 5 L.ha^-1  nitroxin and 10 t.ha^-1 vermicompost had a significant impact on replacement corm characteristics and flower yield of saffron.