Add topsoil before seeding/planting
Overall effectiveness category Evidence not assessed
Number of studies: 1
Background information and definitions
When restoring former grasslands converted to agriculture it is often necessary to introduce seeds of some or all species. One way to do this is through the addition of topsoil from intact grasslands. Translocating topsoil may help to increase the number of seeds in the soil, thereby increasing the probability of grassland plants becoming established. The addition of topsoil may also help to increase soil fertility or reduce the effects of processes that dramatically alter soil structure, such as mining or quarrying. Sowing seeds and planting may further increase the likelihood of colonisation by grassland plants.
The studies detailed in this intervention are direct tests of the effectiveness of adding topsoil before seeding or planting (e.g. by comparison with a seeded or planted plot without topsoil added). Studies that represent comparisons of seeding to unseeded plots can be found in the actions ‘Sow grass seeds’, ‘Sow grassland forb species’ or ‘Sow native grass and forbs’.
Hendry, G.A.F., Thompson, K. & Band, S.R. (1995) Seed survival and persistence on a calcareous land surface after a 32‐year burial. Journal of Vegetation Science, 6, 153–156.
Supporting evidence from individual studies
A replicated, controlled study in 1977–1981 in a formerly mined site in Wyoming, USA (Pinchak et al. 1985) found that adding topsoil before seeding increased plant species richness and biomass of seeded species in most cases, and reduced biomass of species that were not sown in most cases. Areas where topsoil was added and seeds sown had higher plant species richness (4.7–5.2 species/plot) than areas where no topsoil was added but seeds were sown (4.0 species/plot). In six of nine comparisons, the biomass of seeded species was higher in areas where topsoil was added and seeds were sown (445–984 kg/ha) than in areas where no topsoil was added but seeds were sown (180–410 kg/ha). In five of nine comparisons, the biomass of non-seeded species was lower in areas where topsoil was added and seeds were sown (189–952 kg/ha) than in areas where topsoil was not added but seeds were sown (448–1,115 kg/ha). In 1977, topsoil was added to a depth of 20–60 cm to fifteen 45.7 x 4.9 m plots, and no topsoil was added to five plots. Seeds of ‘Critana’ thickspike wheatgrass Agropyron dasystachyum, green needlegrass Stipa viridula, slender wheatgrass A. trachycaulum and ‘Rosana’ western wheatgrass A. smithii were sown at a rate of 15.5 kg/ha in all plots. Biomass was sampled by hand in 4–8 x 0.18-m2 quadrats/plot in 1979–1981. Plant species richness was estimated using 50 x 20 cm quadrats (replication unclear).Study and other actions tested