effect of different levels of biological fertilizers and mushroom compost on flower yield and characteristics of saffron corms (crocus sativus l.) in an organic farming system

in recent years the use of organic and biological modifier as an environmental friendly replacement for chemical fertilizers has been used more. in order to study the effect of different levels of biological fertilizers and mushroom compost on flower yield and characteristics of saffron corms (crocus sativus l.), a split plot experiment based on rcbd design with three replications was conducted in 2009-2011 growing season in research farm of ferdowsi university of mashhad, iran. plant growth promoting rhizobacteria (use and non-use of nitroxin) and spent mushroom compost levels (smc) (0, 20, 40, 60, 80, 100 t ha-1) were considered as the main and sub factors. the results showed that nitroxin had positive effect on all studied traits, for example the use of nitroxin increased number of buds per corm by 12 percent compared to the control. based on the results, levels of 20, 60, 80 and 100 t ha-1 of mashroom compost increased the total weight of corm without scale by 48, 24, 30 and 29 percent respectively compared to the control. interaction effect of plant growth promoting rhizobacteria and different levels mushroom compost was significant on flower yield, so that in condition of use and non-use of nitroxin, levels of 60 and 100 t ha-1 mashroom compost were better than other treatments. according to the results, nitroxin in combine with 40, 60 and 80 t ha-1 mushroom compost increased stigma yield 77, 66 and 30 percent, compared to the same levels in condition of non-use of nitroxin. in general, the results showed that it seems use of biological fertilizers and appropriate amount of mushroom compost in addition to the maintaining stability of agroecosystems, can improve quantitative and qualitative characteristics of saffron.