Physicochemical and biochemical properties of an acid soil under potato culture amended with municipal solid waste compost

Purpose A field trial was conducted on a silty-loam soil under potato culture in NW Spain, to assess the effect of municipalsolid waste (MSW) compost in a heavily fertilized acid soil.Methods Three doses of compost (0, 30 and 60 Mg compost ha−1 soil) or inorganic fertilization (~ 140 N: 120 P2O5:240 K2Okg ha−1 soil) were assayed. The effects of compost on soil physical, chemical (nutrient status and potentially toxictrace elements) and biochemical properties were evaluated after 1 and 5 months.Results Compost addition at the highest dose decreased bulk density and increased soil porosity and soil stability againstwater erosion. Soil pH, total organic C and N, cation exchange capacity and available P, Ca, Mg and K were also higher incompost-amended soils, whereas no effect on NH4+-N and NO3−-N was observed. Compost significantly increased soil microbialbiomass and dehydrogenase activity. Due to the high nutrient status in the control soil, potato yield was not increasedby compost or inorganic fertilization. A negative consequence of compost addition was the increased extractability of tracemetals such as Zn, Cu, Pb and Ni, although their total concentrations in soil or in potato tubers did not increase with respectto the control.Conclusions Overall, results show that positive effects of MSW compost can be expected even in rich soils that do not needfertilization for maintaining their productive function in the short-term. These positive effects prove the benefits of recyclingurban wastes in agricultural soils as a sustainable way of waste management.