Effect of filling materials on reconstructed soil phosphorus adsorption and desorption in mining area

Abstract

Utilization of alternative soil substrates for minesoil reconstruction can affect the nutrient status of reclaimed minesoil (RMS), particularly the availability of phosphorus. This study investigated the adsorption and desorption capacities of phosphorus in three typical reclamation lands using coal gangue (CGR), lake mud (LMR), and Yellow River sand (YSR) as filling materials. The results showed that (i) the phosphorus adsorption capacity of all RMS samples was lower than that of the normal cultivated soil (NCS), the YSR was lower than the CGR and LMR in phosphorus adsorption capacities, while the YSR had better phosphorus desorption capacity than the CGR and LMR. (ii) The specific surface area, pore size, soil texture, mineral composition, functional group composition, and iron/aluminum element content of RMS were varied after the filling of alternative soil substrates, and (iii) the surface characteristics played a vital role in driving the phosphorus adsorption-desorption, while soil texture, and organic matter drove the phosphorus desorption behavior via non-linear ways. This study reveals the difference of phosphorus adsorption-desorption in RMS, and provides a theoretical basis for the rational utilization of alternative soil substrates and the improvement of reclamation land in coal mining subsidence areas.