Replacing chemical fertilizers with organic and biological ones in transition to organic farming systems in saffron (Crocus sativus) cultivation.

To evaluate the response of saffron to animal manure, and biological and chemical fertilizer in an arid climate, an experiment was performed as split plots based on a randomized complete blocks design with three replications during three consecutive crop growth seasons (2015-2018) at the Research Farm of University of Gonabad, Iran. The experimental treatments included application (60 t ha) and non-application (control) of manure as the main plot and the use of biosulfur (5 kg ha), biophosphate (3 L ha), nitroxin (3 L ha), chemical fertilizer (150, 100, and 100 kg ha of urea, triple superphosphate, and potassium sulfate, respectively), and no fertilizer application (control) as the sub-plot. The results showed a highly significant response of the quantitative traits of saffron to the application of manure, which increased the leaf, flower, and corm indices of saffron by a mean of 15.