Add sulphur to soil before seeding/planting

Overall effectiveness category Evidence not assessed
Number of studies: 2
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Effectiveness

not assessed
Certainty

not assessed
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

Adding sulphur to soils can increase their acidity (Neilsen et al. 1993). Alongside seeding or planting of grassland species, adding sulphur may increase the establishment and colonisation of plant species that are adapted to acidic conditions.

The studies detailed in this intervention are direct tests of the effectiveness of adding sulphur to soil before seeding or planting (e.g. by comparison with an untreated but seeded or planted plot). 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’.

_{Neilsen, D., Hogue, E., Hoyt, P. & Drought, B. (1993) Oxidation of elemental sulphur and acidulation of calcareous orchard soils in southern British Columbia. Canadian Journal of Soil Science, 73, 103–114.}

Study locations

Key messages

Two studies examined the effects of adding sulphur to soil before seeding/planting on grassland vegetation. One study was in the UK and one was in the USA.

VEGETATION COMMUNITY (2 STUDIES)

Overall richness/diversity (1 study): One of two replicated, controlled studies (one of which was randomized and paired) in the UK and USA found that adding sulphur to soil before sowing seeds reduced plant species richness. The other study found no change in overall plant species richness.
Native/non-target species richness/diversity (1 study): One replicated, controlled study in the USA found that adding sulphur to soil before sowing seeds did not alter the number of native plant species.

VEGETATION ABUNDANCE (2 STUDIES)

Overall abundance (1 study): One replicated, randomized, paired, controlled study in the UK found that adding sulphur to soil before sowing seeds reduced overall vegetation cover.
Sown/planted species abundance (1 study): One replicated, randomized, paired, controlled study in the UK found that adding low amounts of sulphur to soil before sowing seeds increased the cover of three of six sown species.
Native/non-target species abundance (1 study): One replicated, controlled study in the USA found that adding sulphur to soil before sowing seeds did not alter the cover of native plant species.

VEGETATION STRUCTURE (0 STUDIES)

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 replicated, randomized, paired, controlled study in 1993–1996 in a former arable field in Suffolk, UK (Owen & Marrs 2000) found that adding sulphur to soil before sowing seeds reduced overall vegetation cover and species richness but low amounts of sulphur increased the cover of three of six sown species. After two years, plots where sulphur was added to the soil before sowing had on average lower overall vegetation cover (0–93%) and fewer plant species (0–15 species/plot) than plots where no sulphur was added before sowing (118%; 19 species/plot). Low rates of sulphur addition (1–4 tonnes/ha) increased the cover of three of six sown species (common bent Agrostis capillaris, sheep sorrel Rumex acetosella, buck’s-horn plantain Plantago coronopus), while the three other species (sheep fescue Festuca ovina, velvet grass Holcus lanatus, sheep’s-bit Jasione montana) had the highest cover in untreated plots (see original paper for details).. In August 1993, sulphur was added to six 2.5 x 2.5 m plots within each of three blocks (at rates of 1, 2, 4, 8, 10 and 12 tonnes/ha) and rotovated into the soil to a depth of 5–10 cm. One plot/block had no sulphur added. In October 1994, all plots were sown with a seed mixture of 16 plant species at a rate of 45 kg/ha. In August and September 1995 and1996, species richness and vegetation cover were estimated using a 1 x 1 m quadrat randomly placed in the centre of each plot.
Study and other actions tested
Referenced paper
Owen K.M. & Marrs R.H. (2000) Acidifying arable soils for the restoration of acid grasslands. Applied Vegetation Science, 3, 105-116.
A replicated, controlled study in 2008–2013 in a former arable field in Massachusetts, USA (Neill et al. 2015) found that adding sulphur to the soil before sowing native grass and forb seeds did not alter the cover and species richness of native plants or total plant species richness compared to sowing without sulphur. In the first year after sowing, the average cover and richness of native plant species and total plant species richness did not differ significantly between plots with sulphur added (native plants: 23 % cover, 8–10 species/plot; total: 20–21 species/plot) and plots with no sulphur added (native plants: 36% cover, 11 species/plot; total plants: 23 species/plot). The same was true five years after sowing (native plants: 40–64% vs 59% cover, 11 vs 10 species/plot; total plants: 18–21 vs 17 species/plot). In October–November 2008, fifteen 5 x 5 m plots had sulphur (91–273 g/m²) tilled into the soil before native grass and forb seeds of 26 species were sown, while in five other plots seeds were sown but no sulphur was added. All plots were tilled before treatment/seeding to remove non-native plants. Vegetation was surveyed in a 3 x 3 m quadrat placed in the centre of each plot in July and August 2009 and 2013.
Study and other actions tested
Referenced paper
Neill C., Wheeler M.M., Loucks E., Weiler A., Von Holle B., Pelikan B. & Chase T. (2015) Influence of soil properties on coastal sandplain grassland establishment on former agricultural fields. Restoration Ecology, 23, 531-538.

Please cite as:

Martin, P.A., Ockendon, N., Berthinussen, A, Smith, R.K. and Sutherland W.J. (2021) Grassland Conservation: Global evidence for the effects of selected interventions. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

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This Action forms part of the Action Synopsis:

Grassland Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Mow before or after seeding/planting Action Link	Evidence not assessed	10	Synopsis Link
Sow grassland forb species Action Link	Evidence not assessed	1	Synopsis Link
Remove leaf litter before seeding/planting Action Link	Evidence not assessed	3	Synopsis Link