Abstract: In order to figure out interspecific associations among dominant species in naturally colonized plant communities on coal gob piles, the interspecific associations among 15 dominant species in naturally colonized plant communities on coal gob piles of Datong mining area in Shanxi, China were studied by using 〖KG*3〗χ²test, Pearson correlation coefficients and Spearman rank correlation coefficients in this study. The results showed that the interspecific associations of most speciespairs among 15 dominant species were not significant, which illustrated that the naturally colonized plant communities on the coal gob piles of Datong mining area had simple community structures and were still at the early or middle stage of succession. The dominant species pairs of Agropyron desertorum or Elymus dahuricus and Rosa xanthina, R. xanthina or Clematis fruticosa and Ulmus pumila showed extremely significant or significant positive correlation; these species are species of zonal distribution with strong ecological adaptability to drought, cold weather and poor soil fertility, which could be mixedly planted as the pioneer species for local coal gob piles revegetation. Based on Spearman’s rank correlation coefficients, the 15 dominant species were divided into 3 ecological species groups. Soil moisture was the key factor causing the differentiation of the ecological species groups.

Key words: low nitrogen stress, growth, cucumber, purified humic acid, nutrient absorption.