Abstract: To reveal the soil improvement effect and nutrient use strategy of forest plantations in opencast coal mine reclamation area, we examined the effects of Salix matsudana plantation and Populus davidiana plantation on soil physicochemical properties after 10 years of land reclamation, analyzed the concentrations of carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn) and manganese (Mn) in each organ and leaf litter of those two tree species, and explored the nutrient resorption characteristics and influencing factors. The results showed that, compared to the unmanaged grassland, both S. matsudana and P. davidiana plantations increased soil water content, capillary porosity, and concentrations of organic C, total N, total P, total Ca, available N, and available P, while decreased soil bulk density, pH value, and concentrations of total K, total Mg, total Fe, total Zn, and total Mn. Nutrient resorption efficiencies of all examined elements in the two tree species were all greater than 0. The nutrient concentrations were usually higher in leaves, branches, and fine roots than those in trunks and coarse roots. P. davidiana had higher N resorption efficiency and N concentrations in organs and soils than S. matsudana. N resorption efficiency was significantly positively correlated with N concentration in mature leaves and soil. Therefore, planting S. matsudana and P. davidiana in reclamation area of opencast coal mine could enhance soil water retention, balance soil pH, increase concentrations of C, N, P and Ca, but reduce concentrations of K, Mg, Fe, Zn and Mn. P. davidiana had higher nutrient conservation and fertilization abilities compared to S. matsudana.

Key words: Populus davidiana, Salix matsudana, nutrient allocation, micronutrient, mine ecological restoration