The possibility of replacing chemical fertilizer with organic manure in saffron cultivation at different levels of corm density under Northern Khorasan climatic conditions

Due to climate change it seems that the suitable area for production of saffron is shifting towards the Northern area of Khorasan. On the other hand, corm density and nutrient management are important factors in saffron production. To find out the credibility of this assumption, an experiment was conducted based on a randomized complete blocks design arranged in split plot with three replications in a field located 10 km of Shirvan during the 2013-14, 2014-15 and 2015-16 growing seasons. Corm density (50, 100 and 150 corm.m^-2) and different amounts of chemical and organic manure [No fertilizer (Control), amount of urea, triple super phosphate and potassium sulfate 100, 100, 50 (C1), 200, 200, 100 (C2) and 300, 300, 150 (C3), cow manure consumption based on 100 kg.ha^-1 urea (3066 kg.ha^-1), based on 200 kg.ha^-1 urea (6132 kg.ha^-1) and based on 300 kg.ha^-1 urea (9198 kg.ha^-1)] were allocated to the main and sub-plots, respectively. Three year average of harvest showed that flower and corm traits improved with increasing corm density and cow manure consumption, while the highest density compared to minimum density caused increasing flower number, fresh flower yield, dried stigma yield, daughter corm number and corm yield by 35, 61, 29, 180 and 122 percent, respectively. Also the highest amount of cow manure compared to control increased flower number, fresh flower yield, dried stigma yield and corm yield by 32, 51, 38 and 51 percentages, respectively. Therefore, more flower and corm yield were obtained in 9198 kg.ha^-1 cow manure consumption with 150 corm.m^-2 planting density. Therefore, it seems that the production of saffron is suitable using with organic manure compared with chemical manure. Moreover, saffron planting with high corm density is a solution for improving the yield of saffron in the early years of planting.