Add mulch and fertilizer to soil

How is the evidence assessed?

Source countries

Key messages

  • One randomized, controlled study in the USA found that adding mulch and fertilizer did not increase the seedling abundance of seven shrub species. The same study also reported no change in grass cover.

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

  1. A randomized, controlled study in 1997–1999 in a sagebrush scrub shrubland that had been invaded by grass and burnt by wildfires in California, USA (Cione et al. 2002) found adding mulch, followed by addition of nitrogen fertilizer did not increase the seedling abundance of seven shrub species or reduce grass cover after one year. The areas where mulch and fertilizer were added did not differ in the number of shrub seedlings for seven of seven species (0 seedlings/m2) from areas where mulch and fertilizer were not added (0 seedlings/m2). There was also no significant difference in grass cover between areas where mulch and fertilizer had been added (83%) and areas where mulch and fertilizer were not added (84%). In 1997 mulch and fertilizer were added to five randomly located 5 m x 5 m plots, while in five other plots no mulch or fertilizer were added. In spring 1997 plots were surveyed for grasses using two 0.25 m x 0.5 m quadrats/plot and two 0.5 m x 1 m quadrats/plot for shrubs.

    Study and other actions tested
Please cite as:

Martin P.A., Rocha R., Smith R.K. & Sutherland W.J. (2019) Shrubland and Heathland Conservation. Pages 493-538 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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Shrubland and Heathland Conservation

This Action forms part of the Action Synopsis:

Shrubland and Heathland Conservation
Shrubland and Heathland Conservation

Shrubland and Heathland Conservation - Published 2017

Shrubland and Heathland synopsis

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What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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