Abstract: By using χ² test for 2×2 contingency table and Spearman’s rank correlation coefficient,We studied the interspecific relationships of dominant species in Oxytropis coerulea community in Wutai Mountains.A total of 18 plant species and 153 species-pairs interspecific association were investigated.The results indicated that only 6 species-pairs showed significant or highly significant association in χ² test,while 18 species-pairs had significant or highly significant correlation in Spearman’s rank test.Therefore,Spearman’s rank test was more accurate and reliable.Generally,most species were not closely related with each other.The species with similar biological features tended to be positively associated and correlated,while those with different biological features and different adaptabilities to the habitats or existing inter-competitions tended to be negatively associated and correlated.

Key words: Controlled release fertilizer, Nutrient use efficiency, Rice, Single basal application