Evaluation the Possibility of chemical fertilizer replacement with organic and Biological fertilizers in Saffron (Crocus sativus L.) Cultivation.

Proper fertilizing management is one of the prequisits to reach a sustainable and lucrative agroecological farming system. Integrated nutrients management is that farmer based on type of cultivation, crop nutrients requirement, soil biological quality and also the permissible residual nutrients in products choose required fertilizers among organic, biological, and chemical ones. In this research the effect of variable amounts and resources of fertilizers were evaluated on qualitative and quantitative yield of saffron as one of the most beneficial plants. The experiment was performed on Shahed University Research Farm as factorial in a randomized complete block design with two factors for two years. The first factor was nitrogen fertilizer ( 0, 50 and 100 percentage of the recommended based on soil test) and the second one was non-chemical fertilizers (vermicompost, PGPR bearing biofertilizer and integrated application of vermicompost and biofertilizer). The results of quantitative and qualitative characteristics of saffron vegetative and generative organs indicated that however, applying 100% chemical fertilizer had the positive impact on total quantitative yield, but it strongly reduced the qualitative characters of leaf and stigma. So that applying 100% chemical fertilizer increased dry yields of saffron stima from 0.423Kg/ha in control treatment to 1.350 Kg/ha , while chlorophyll b, safranal and crocin amounts decreased by respectively 13/86% 13/45% and 10/89%. while, half doze applying of chemical fertilizer along with sole or integrated non-chemical fertilizers was more efficient than treatments with 100% chemical fertilizer. Totlly, integrated application of 50% chemical fertilizers along with vermicompost and biofertilizer caused quantitative and qualitative yield increment. This treatment was the first regarding in increasing total numbers of plant components, total fresh and dry yield. In addition, it resulted in a 97.6% increment of stigma dry weight. It is worth noting that the integration of 50% chemical fertilizer and vermicompost caused the highest quality of leaves and stigma. This treatment increased the amounts of chlorophyll a, chlorophyll b, total chlorophyll, leaf phosphorus and picrocrocin respectively by 10/59% 9/34%, 9/96%, 2/66% and 12/70%. In general, the results showed that the substitution of 50% chemical fertilizers with bio-fertilizers and vermicompost could significantly increase yield and quality of saffron. Keywords: Saffron, Integrated fertilization, organic fertilizer, Nutrients, biofertilizer, chemical fertilizer