Add peat to soil (alongside planting/seeding)
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Background information and definitions
Adding peat to soil may increase its acidity. If combination with the addition of seed or plants that favour acid conditions this may help to promote the growth of shrubland plants.
Supporting evidence from individual studies
A replicated, randomized, controlled study in 1991–1993 in former agricultural fields in Norfolk, UK (Davy et al. 1998) found that addition of peat to agricultural soils alongside sowing of seed increased the density of heather Calluna vulgaris seedlings in seven of eight trials, and led to larger heather plants, but no heather seedlings survived after two years. After one year, in seven of eight trials, the density of heather seedlings was higher in areas where peat had been added to agricultural soils and heather seed sown (30–66 seedlings/plot) than in areas where heather seed was sown but no peat had been added (5–16 seedlings/plot). However, after two years no seedlings survived in any plots. After one year heather plants were larger in six of eight trials in areas where peat had been added to soils along with seed (5–58 whorls/plant) than in areas where seed had been sown but no peat had been added to soils (1–15 whorls/plant). Thirty-six water tanks were inserted into the ground in September 1991, twenty-four of which contained a mixture of peat and agricultural soil and 12 of which contained only agricultural soil. All tanks were sown with heather shoots that had been harvested in autumn. 10 cm x 10 cm quadrats were placed in each tank and used to monitor the abundance of heather seedlings between June and September 1992.Study and other actions tested
A replicated, randomized, controlled study in 1992–1997 in an agricultural field that was previously heathland in Suffolk, UK (Dunsford et al. 1998) found that in two of three cases adding peat to soil, followed by sowing of seed of shrubland plants increased cover of common heather Calluna vulgaris compared to seeding alone. In two of three cases common heather cover was higher in areas where peat was added to soil and seed sown (40–49%) than areas where only seed was sown (8%). In 1992 peat was added to 18 randomly located 4 m x 8 m plots and seeds were sown, while only seeds were sown in 6 other plots. Thirty-two 1 m2 quadrats placed in each plot which were used to record the cover of common heather in August 1994 and September 1997.Study and other actions tested