Application of organic mulch can be effective on increasing the flower and corm yields of saffron, by affecting the soil temperature, water availability and organic matter content of soil. In order to investigate the effects of levels of applied wheat straw mulch and different date on flower and corm characteristics of saffron, a field experiment was conducted at Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in the growing years of 2010-2011. For this purpose, a complete randomized block design based on factorial arrangement with three replications and 15 treatments was used. Experimental treatments included different levels of wheat straw mulch (0, 2, 4, 6 and 8 t ha-1) based on surface applying method in three different date (June, August and October). Results of analysis of variance showed that different date and levels of applying wheat straw mulch affected flower number significantly. In addition, interaction affects of different date × levels of applying wheat straw mulch on flower number was also significant. Based on the results, fresh and dried flower and dried stigma yields of saffron was increased significantly, by increasing levels of applying wheat straw mulch in all three date. In addition, applying the wheat straw mulch in different date had significant effects on daughter (replacement) corm more than 10 g and total corm yield of saffron. However, by increasing total corm yield of saffron due to applying wheat straw mulch, total corm numbers of saffron was significantly decreased.

Keywords