The Effect of Nitrogen and Phosphorus Fertilization on Plant Community Along Chronosequences of Reclaimed and Unreclaimed Postmining Soils After Coal Mining

Nitrogen and phosphorus availability drive plant community composition, productivity, and ecosystem functioning. During succession, nutrient availability typically changes as organic matter accumulates in the soil, influencing both nitrogen and phosphorus pools. We assessed nutrient limitation along postmining chronosequences (10–50 years old), including sites reclaimed with alder ( Alnus ) plantations and unreclaimed sites undergoing spontaneous succession. Plots received N (50 kg ha −1 year −1 ) or P (5 kg ha −1 year −1 ) fertilization or served as controls, applied over 3 years. Vegetation surveys were conducted in the first and third years, and aboveground biomass of Calamagrostis epigejos was collected in the third year for chemical analysis. Redundancy analysis revealed a significant effect of fertilization on community composition at unreclaimed sites, explaining 7% of the variance, whereas the effect was not significant at reclaimed sites and explained only 2% of the variance. On unreclaimed sites, N fertilization increased herb‐layer cover, reduced species evenness and turnover, but did not accelerate vegetation change. Although the effects of N fertilization are significant in some cases, they are relatively small. Phosphorus fertilization had negligible effects on vegetation in both site types. Nutrient content analysis of C. epigejos biomass indicated that the plant community was more limited by P than by N. However, P fertilization had limited potential to alleviate this limitation. This effect likely results from alkaline soils, in which phosphorus is bound in insoluble compounds that are unavailable to plants. Moreover, the effects of both fertilizers do not appear to be clearly positive in terms of ecosystem restoration.