Relationship between nutrient concentration in saffron corms and saffron yield in perennial fields of South Khorasan province

Saffron (Crocus sativus L.) is one of the most important exports products in Iran that proper concentration of nutrients is particularly important in the development and production. Since saffron is reproduced by corm, so always been considered production of replacement corms through appropriate nutrition; and concentration of element in corm in specific stage of growth and development has high correlation with plant yield. Therefore, this study was conducted to determine nutrients concentration in corm of saffron in perennial fields of Qaen and Nehbandan in South Khorasan in 2015. The information of two regions (Qaen and Nehbandan) were collected from 3, 5 and 7 years-old fields. Then, three fields with at least 500 m2 under cultivation selected for each age of 3, 5 and 7 years fields and 3 plots from each field and one corm sample from each plot were selected. The concentration of phosphorus (P), potassium (K), nitrogen (N) and iron in corm of saffron were analyzed based on standard laboratory methods. Results revealed that there were significant differences in N, P, K and iron concentrations of saffron corm (P≤0.01), but the effects were distinct for corm number in different weight groups. The present study showed that in saffron fields, N, P, K and iron concentration in corm were the most effective parameters for saffron yield increment, which regression correlations showed yield increment compeer to the change in these indices. Investigation of nutrients concentration of the corm on saffron yield shows the important role of such elements in yield. Therefore, nutrient concentration in saffron corms affect the plant nutrition, promoting growth and yield of crop. Generally, corm selection with optimum weight for sowing and proper use of nutrients, especially nitrogen, phosphorus, potassium and iron, as well as their correct balance in soil, can be effective in yield increment and stability of soil fertility.