Analysis of the Spatial Variation of Soil Salinity and Its Causal Factors in China’s Minqin Oasis

Table 1

Definitions of the affecting factors for the reference series (soil ).

Affecting factor	Definition	Measurement
()	Elevation of the sample site	Distance above mean sea level
()	Distance to the nearest irrigation canal	The distance between the sample point and the nearest canal
()	Compound topographic index (CTI)	Defined in Section 2.3
()	Vegetation cover	The % coverage of the soil by vegetation
()	Groundwater level	Distance from the ground surface to the top of the groundwater table
()	Groundwater salinity	Total dissolved salt content in the groundwater