Effect of corm residues and its extract on saffron leaf and flower yield under different farm age of saffron (Crocus sativus L.) residual.

One of the most serious problems in saffron production is that it is impossible to plant saffron again in a given farm. Therefore, it is essential to identify the reasons for not being able to plant saffron again in a given farm. This research was carried out in order to investigate the effect of residual soil of saffron, different ages of saffron field, its corm and extract on quantitative production of saffron in factorial as completely randomized design with three replications during 2016-2018, in a personal farm under natural conditions in Torbate Heydarieh, Iran. The first factor was soil age at three levels (including field soil without background of saffron cultivation (control treatment), field soil from which corms had been taken out two years ago, and soil under cultivation of saffron in the fourth year) and the second factor was the application of corm and its extract in three levels (including non-consumption of corm as control, crushed saffron corm 14 tons per hectare and consumption of aqueous extract of saffron corm with a concentration of 50 percent). The results showed that most traits were affected by treatments and their interactions. The cultivation of saffron in the field caused a significant reduction in the amount of leaf and flower components and their yield (more than 17 and 27 %, respectively). Also, using aqueous extract and crushed saffron corm reduced more than 10% of flower and leaf components and their yield. The highest stigma and leaf yield were observed in the control treatment (9.88 and 240.97 kg.ha-1, respectively) and the least stigma and leaf yield were observed in field soil two years after the outcrop and using crushed corms (2.27 and 16.09 kg.ha-1, respectively). So, it can be stated that remnants of saffron corm in the field significantly reduce the growth, reproduction, leaf and flower yield and its components and it is recommended that the cultivated saffron residues of the previous year be taken out from the soil for re-cultivation of saffron so that its harmful effects do not reduce the growth and yield of new saffron.