INFLUENCE OF TOPSOIL ADDITION ON SPECIES DIVERSITY AND ABOVEGROUND BIOMASS OF PLANT COMMUNITY ON THE DAMAGED MINED LAND IN ALTAY, CHINA

Topsoil addition on restoring damaged mine lands is vital for improved infiltration, plant rooting media, enhanced nutrient cycling, and as a potential source of plant propagules to increase plant community diversity. Varying topsoil depth may influence reclamation success. This study assessed the effect of four different topsoil addition depths (0, 4, 8, and 12 cm) on plant community attributes (community coverage, height, species richness, diversity, and production). In 4 grassland, species amount in the mining area were the most at the 8 cm and 12 cm. Percent canopy cover and height of grasses were highest at the 12 cm topsoil depth and lowest at the 0 cm topsoil depth. Species richness(R), diversity indices (H) and dominance indices (D) were highest at the 12 cm topsoil depth and lowest at the 0 cm topsoil depth. Evenness indices (J(sw)) was highest at the 0 cm topsoil depth and lowest at the 8 cm topsoil depth. Aboveground biomass was similar between the 8 cm and 12 cm topsoil depths and higher than 0 and 4 cm topsoil depths. The coverage, height, species richness, diversity and aboveground biomass of grassland community generally increased with variable topsoil depth, while evenness fluctuated. However, there was no significant difference between 8 cm topsoil depth and 12 cm topsoil depth in community cover, plant height, aboveground biomass and diversity indices. And there was positive correlation between community productivity and Shannon-Wiener and Simpson indices. Therefore, for the Kurt Kizu mining area, considering comprehensively economic investment against ecological benefits when restoring damaged steppe, the appropriate topsoil addition depth for grassland vegetation restoration is 8 cm.