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

Table 4

Grey relational grade () for each affecting factor and the resulting ranking for the two main land use and cover types.

Reference factor	Affecting factor	Definition		Ranking	Relationship
Cropland
	()	Distance to irrigation canals	0.847	1	Positive
	()	Groundwater level	0.787	2	Negative
	()	CTI	0.783	3	Positive
	()	Elevation of the sample site	0.780	4	Negative
	()	Groundwater salinity	0.777	5	Positive
	()	Vegetation cover	0.760	6	Negative
Sparse grassland
	()	Groundwater salinity	0.755	1	Positive
	()	Vegetation cover	0.742	2	Positive
	()	Elevation of the sample site	0.714	3	Negative
	()	Groundwater level	0.711	4	Positive
	()	CTI	0.708	5	Negative
	()	Distance to irrigation canals	0.662	6	Negative

Positive relationships mean that a high value of the affecting factor increased ; negative relationships mean that a high value decreased .