Studying the possibility of replacing manure with other organic amendments in saffron (Crocus sativus L.) cultivation at different mother corm weights

This study was conducted to investigate the effect of different organic amendments (cow manure, humic acid (Humax® 95–WSG), an organic-mineral-based emulsion (Omic®) and unfertilized control) and mother-corm weight (0 to 4 g, 4.1 to 8 g and 8.1 to 12 g) on flower and corm yield of saffron. The experiment was conducted as factorial experiment in randomized complete block design with three replications in the Research Complex of Medicinal Plants, ACECR of Southern Khorasan Province, Iran in 2017-18. According the results, evaluating the main effect of nutrition factor revealed no significant impact on most studied traits in the first year. However, in the second year and during the 21-day period of saffron flowering, cow manure treatment increased stigma dry weight by 77.3, 71.7 and 58.9% compared with control, Humax and Omic treatments, respectively. By fitting the regression line between the cumulative dry weight of the stigma and days after flowering, it was found that stigma dry weight increased 19.1, 11.43, 10.92 and 10.65 mg.day-1 in cow manure, Omic, Humax and control treatments, respectively. In addition, the highest flower dry weight with 2858 mg.m-2 was recorded in cow manure treatment. The highest and lowest amount of the studeid tratis in both years belonged to big and small corm treatments, respectively. In the first year, stigma dry weight in big corm treatment with 22.28 mg.m-2 was about 190 times higher than that of small one. However the difference in the second year fell to less than 3 times. In addition, the highest number (466.36 m-2) and weight (936.559 g. m-2) of daughter corms were obtained in big mother corms treatment. In the second year however by the reduction of the differences between mother corm weight treatments, stigma dry weight, flower dry weight and number of flowers in big and medium corm treatments were not statistically significant. Overall, the results of this study showed that the advantages of using manure in saffron cultivation due to its unique characteristics, such as improving the physical conditions of the soil is not compensable by other organic amendments. Moreover, the avoidence of planting mother corms less than 4g because of their adverse effects on saffron yeild is of main importance in saffron cultivation and must be considered by farmers.