Add gypsum to soil (alongside planting/seeding)

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

30%
Certainty

10%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Addition of gypsum to soil can help to increase water infiltration into soils. Combining this with the addition of plants or seeds may help to increase the survival and growth of introduced plants.

Study locations

Key messages

One randomized, controlled study in South Africa found that adding gypsum to soils and sowing seeds increased survival of seedlings for one of two species

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A randomised, controlled study in 1994–1998 in a succulent karoo shrubland in Western Cape, South Africa (Beukes & Cowling 2003) found that applying gypsum, followed by sowing the seeds of shrubland species increased the number of seedlings of these species, and increased seedling survival of one of two species. Applying gypsum followed by sowing the seeds of the species Karoo bietou Tripteris sinuata, Spiny ruschia Ruschia spinosa and Gha grass Chaetobromus dregeanus increased the number of seedlings of these species compared plots where unmulched, unseeded plots (data not provided). Applying gypsum followed by seeding increased the survival of seedlings of Karoo bietou relative to areas that where gypsum had not been applied and that were not seeded (data not provided), but there was no difference in the survival of Gha grass. In 1994 eight 12.5 m² plots were established. In four plots gypsum (CaSO₄) was applied at a rate of 5 tonnes/ha, followed by sowing of the seeds of shrubland species. In the other four plots no mulch was applied, and no seeds were sown. Seedlings in each plots were counted annually between 1994 and 1998.
Study and other actions tested
Referenced paper
Beukes P.C. & Cowling R.M. (2003) Evaluation of restoration techniques for the Succulent Karoo, South Africa. Restoration Ecology, 11, 308-316.

Please cite as:

Martin, P.A., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Shrubland and Heathland Conservation. Pages 483-525 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Shrubland and Heathland Conservation

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Add fertilizer to soil (alongside planting/seeding) Action Link	Unknown effectiveness (limited evidence)	2	Synopsis Link
Add peat to soil (alongside planting/seeding) Action Link	Unknown effectiveness (limited evidence)	2	Synopsis Link
Add gypsum to soil (alongside planting/seeding) Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link