The efficacy of soil ameliorants to improve early establishment in trees and shrubs in degraded Eucalyptus gomphocephala woodlands

Published source details Ruthrof K., Douglas T., Calver M., Craig M., Dell B. & Hardy G. E. St J. (2012) The efficacy of soil ameliorants to improve early establishment in trees and shrubs in degraded Eucalyptus gomphocephala woodlands. Pacific Conservation Biology, 18, 310-318.
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This study is summarised as evidence for the following.

	Action	Category
	Improve soil quality after tree planting (excluding applying fertilizer) Action Link
	Use fertilizer after tree planting Action Link

Improve soil quality after tree planting (excluding applying fertilizer)

A randomized, replicated, controlled study in 2008–2009 in two sites in degraded tuart Eucalyptus gomphocephala woodlands in Western Australia (Ruthrof et al. 2012) found that adding soil enhancers (other than fertilizers) had mixed effects on tuart seedling survival and height but no effect on seedling health. At one site, seedlings were taller in plots treated with a biological stimulant for soil microbes (approx. 106 cm) than in untreated plots (approx. 82), but smaller where a clay-based amendment was added (approx. 63 cm; data taken from a graph). No other treatments had an effect on height (see paper for additional data). None of the treatments increased survival rate. At a second site, seedlings height and survival were higher in plots with fertilizer + moisture retaining chemicals (survival: 80%; height 39 cm) or fertilizer + moisture retaining chemicals + metal ion retaining agent (survival: 82%; height 37 cm) than in untreated plots (survival: 54%; height 28 cm). However, they did not differ from plots treated with fertilizer tablets (survival: 96%; height 50 cm). None of the other treatments had an effect on survival or height. None of the treatments had an effect on plant health class at either site. Each site had three blocks each with six plots (6 × 10 m) containing 20 tuart seedlings. Each plot received one of the following treatments: fertilizer tablets, a clay-based amendment, a biological stimulant for soil microbes, fertilizer + moisture retaining chemicals, fertilizer + moisture retaining chemicals + metal ion retaining agent, or was left untreated (for details see study, fertilizer treatments differed). After one year the survival, growth and health of all seedlings was assessed. Seedling health class was based on general vigour, crown density, colour and amount eaten by herbivores.
Use fertilizer after tree planting

A randomized, replicated, controlled study in 2008–2009 in two sites in degraded tuart Eucalyptus gomphocephala woodlands in Western Australia (Ruthrof et al. 2012) found that a range of soil enhancers including fertilizer did not increase tuart seedling health, but had a mixed effect on seedling survival and height. At one site, seedling survival and height were greater in plots treated with fertilizer tablets (survival: 96%; height 50 cm), fertilizer + moisture retaining chemicals (survival: 80%; height 39 cm), fertilizer + moisture retaining chemicals + metal ion retaining agent (survival: 82%; height 37 cm) than in untreated plots (survival: 54%; height 28 cm). At a second site, there was no effect of treatments on seedling survival or height (see paper for details). Health class was not affected by any of the treatments, at either site. Each site had three blocks each with six plots (6 × 10 m) containing 20 tuart seedlings. Each plot received one of the following treatments: fertilizer tablets, a clay-based amendment, a biological stimulant for soil microbes, fertilizer + moisture retaining chemicals, fertilizer + moisture retaining chemicals + metal ion retaining agent, or was left untreated (for details see study, fertilizer treatments differed). After one year the survival, growth and health of all seedlings was assessed. Seedling health class was based on general vigour, crown density, colour and amount eaten by herbivores.