Regression Analysis for Yield Comparison of Saffron as Affected by Physicochemical Properties of the Soil, Case Study in Northeast of Iran

The present research was conducted during 2015–2017 to compare the yield of saffron as affected by soil characteristics in Vamenan village, Golestan Province, Iran, which is regarded as a new planting zone of this plant compared to Ghayen region, South Khorasan Province, Iran. Sampling was done from 30 saffron farms with three replications, i.e., 90 profiles were sampled from 3 to 5 years old farms in each of the studied areas. Jarque–Bera and White tests and Durbin–Watson statistics were utilized to estimate the impact rate of soil properties on saffron yield. The results indicated that the effects of soil electrical conductivity on yield in Ghayen were negative and significant, whereas amounts of clay and silt significantly and positively affected the yield with corresponding values of − 0.04, 0.19 and 0.1, respectively. However, the effect of organic matter and available potassium level on saffron yield in Vamenan was positive and significant, and their values were 1.45 and 0.19, respectively. The average saffron yield in Vamenan was 5.3 kg ha −1 higher than that of Ghayen. Therefore, it can be stated that Vamenan may be considered as a suitable location for saffron cultivation.