Soil quality evaluation of windy desert region after coal mining subsidence based on discriminant and factor analysis

In order to provide theoretical supporting for land utilization planning and management in windy desert region, canonical discriminant analysis and factor analysis were used to distinguish and study the soil quality of two subsidence areas (SAs) respectively subsided in 2004 and 2005 in Bulianta coal mining area located at south rim of Maowusu desert. The results showed that soil moisture content, hardness, total N and P of the two SAs were significantly lower than control area (CA) (p<0.05). At partial slope positions with serious ground surface disturbance, volume weight declined remarkably (p<0.05) while soil porosity increased remarkably (p<0.05). Compared with the CA, total K and organic matter of the two SAs showed no significant variation (p>0.05), and available nutrient displayed an activating tendency on the whole. With the calculation by a canonical discriminant function which mainly reflects the disturbance degree of soil nutrient, sample plots of CA and SAs respectively subsided in 2005, 2004 can be divided into 3 grades, which including “no effect”, “had effect” and “seriously effect”. 11 soil quality indexes were summarized to 5 comprehensive factors by factor analysis, and comprehensive factor scores of soil quality of the sample plots in SAs were represented visually with radar diagrams and scatter diagrams. Canonical discrimination function distinguished the situation of soil quality of CA and each SA well, and factor analysis reflected characteristic of soil quality variance of each SA comprehensively and visually.