Uptake Efficiency of Nitrogen in Saffron (Crocus sativus L.) as Affected by Irrigation Levels and High Corm Density

The effects of irrigation levels and high corm density on replacement corms behavior and nitrogen uptake of saffron (Crocus sativus L.) were studied in a field experiment as split-plot based on a randomized complete block design with three replications at Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during the years of 2012 and 2013. The irrigation levels of saffron based on water requirement (50, 70 and 100 %) and high corm density (50, 100, 200 and 300 corms per m2) were allocated to the main and sub plots, respectively. Based on the results, the lowest nitrogen content in replacement corm and aerial part of saffron (6.02 and 5.62 gm-2, respectively) were observed by sowing 50 corms per m2 + 50 % irrigation. In both years, nitrogen uptake efficiency, nitrogen use efficiency and nitrogen harvest index of saffron was significantly decreased by increasing the corm planting density. In the second year, nitrogen uptake efficiency, nitrogen use efficiency and nitrogen harvest index were more than the first year. It seems that higher planting densities, which named dense corm planting, can be considered as an alternative approach for increasing nitrogen use efficiency in saffron.