Effects of Plant and Tree Roots Decomposition on Soil Nutrients in an Abandoned Pyrite Mining Area in China

The study aims to explore the effect of fine root decomposition on soil nutrients in pyrite mining areas and provide a basis for plant selection in the vegetation restoration process in mines.With the decomposition bag method, the root decomposition characteristics of three typical plants (Castanea mollissima (C.mollissima), Betula luminifera (B.luminifera) and Symplocos tetragona (S. tetragona)) in Guizhou Dafang Pyrite Mining Area and their effects on soil nutrients.The loss rates of fine root decomposition of the three plants decreased according to the following order: S. tetragona> B. luminifera>C.mollissima.After a year of decomposition, the mass loss rates of the three plants were respectively 76.00%, 66.28% and 59.36%.Among the three plants, S. tetragona had the faster rate of fine root decomposition.Organic carbon presented a significant positive correlation with total nitrogen and nitrate nitrogen (P<0.05).Root activities of S. tetragona and C. mollissima could increase nitrate nitrogen content.Therefore, in abandoned mining areas with a single nutrient source, the plant configuration of S. tetragona and C. mollissima as well as some native herbaceous plants (such as Lolium perenne L., Cynodondactylon (Linn.)Pers.and Agrostisstolonifera Roth.) are more conducive to the accumulation of nutrients and ecological restoration.At the same time, heavy metal elements in soil may affect nutrient changes during fine root decomposition.