Soil Quality Assessments in Some Iranian Saffron Fields

Little information is available about Soil Quality (SQ) in Iran, especially in saffron [Crocus sativus (L.) Iridaceae] fields. The objectives of this research were to: (i) Establish a Minimum Data Set (MDS) for quantifying soil quality in saffron fields; (ii) Evaluate soil quality status using two indices of Integrated Quality Index (IQI) and Nemoro Quality Index (NQI), and (iii) Investigate the relationship between soil quality and the economics of saffron production. Thirty soil samples were collected from the Ghayen area of South Khorasan, Iran, and analyzed for soil physical and chemical properties. Principal Component Analysis (PCA) was used to identify a Minimum Data Set (MDS) consisting of sand, Relative Field Capacity (RFC), zinc, SAR, Ca, CaCO3, Fe and Bulk Density (BD). Soil Quality was evaluated using the IQI and the NQI for both the Total Data Set (TDS), and MDS. Four SQ indices i.e., IQITDS, IQIMDS, NQITDS, and NQIMDS were used to evaluate soil quality in saffron fields in the study area. A significant correlation (P< 0.05) was shown between the IQITDS (r= 0.44), NQITDS (r= 0.41) and economic yield of saffron. Correlation analysis indicated that the IQITDS performed better compared to the NQITDS for evaluating the soil quality. Use of the TDS with the IQI index was the most effective approach for evaluating SQ in saffron fields.