Priming of soil structural and hydrological properties by native woody species, annual crops, and a permanent pasture

Impermeable subsoil is a major constraint to root growth and water infiltration in most duplex soils of Australia, but can be ameliorated by channels or biopores created by dead and decomposed roots of plant species that are adapted to these soils. In the current study, we evaluated whether a 6-year phase of native woody species planted in belts created sufficient biopores to significantly improve the soil structure of a yellow Chromosol, us (but not E. nitens ) plantations in Tasmania because of low mean minimum temperatures. Conditions within 3 weeks of planting induced severe photoinhibition in non-shaded seedlings. This was associated with increased anthocyanin and photodamage in non-shaded E. nitens and E. globulus . As a result, there was 20% mortality in non-shaded E. globulus . In contrast, shaded seedlings of both species had levels of photoinhibition and anthocyanin that were largely similar to those before planting and there was no photodamage. Levels of anthocyanin indicated that its synthesis responded to the severity of photoinhibition. Height growth and levels of mortality indicated that cold-induced photoinhibition, and not frost tolerance alone, determines the range of environments where E. globulus can be successfully planted. In contrast, the tolerance of E. nitens seedlings to cold-induced photoinhibition may be a factor in the demonstrated success of this species as a high-altitude plantation species. Keywords: subsoil constraint, Acacia spp., Eucalyptus spp., Casuarina spp., biological drilling, porosity, hydraulic conductivity, preferential flow. Australian Journal of Soil Research 40(2) 207 - 219 Full text doi:10.1071/SR01038 © CSIRO 2002