A comparison of the effects of four arable crops on the fertility depletion of a sandy silt loam destined for grassland habitat creation Original Research Article

Species-rich grassland habitat creation depends on low soil fertility for success. However, past eutrophication of potential sites frequently requires fertility depletion before the establishment of species-rich swards. Therefore, this experiment investigated the effectiveness of four arable crops in depleting the fertility of a sandy silt loam. Barley, potatoes, maize and tobacco were grown for two full seasons without fertiliser and the changes in several soil parameters (total nitrogen, phosphorus and potassium; nitrate; extractable P and K; soil pH and loss-on-ignition) were compared. Bioassays using Lolium perenne as a test species were performed. There were major changes in available nutrients, with significant differences between treatments after two years. Barley depleted soil concentrations of nitrate, extractable phosphorus and bioassay yields significantly more than other treatments. Therefore, we believe that cereal growth over two years or more provides the best crop treatment for fertility depletion prior to habitat creation. Although no continuing decline in total nutrient pools was achieved, it is postulated that the removal of available soil nutrients immediately prior to seeding allows the establishment of a species-rich sward, which can be maintained subsequently by appropriate management.