Preliminary observations on the effect of removal of black bluebush (Maireana pyramidata) and Pearl Bluebush (M. sedifolia) on shrub regeneration, herbage production and erosion potential.

Abstract

The effects of mechanical removal of shrub tops and grazing on two bluebush communities, one with Maireana pyramidata (black bluebush)and the other with M. pyramidata and M. sedifolia (pearl bluebush) as co-dominants, were examined on the western edge of the Riverine Plain in New South Wales Measurements were made on shrub regeneration, the relationship of shrub units to a critical value for an erosion index, the change in soil surface levels, and the growth of herbaceous plants over time Shrub regeneration was slower under grazed than ungrazed conditions and occurred mainly from basal shoots of established plants rather than from seedling establishment. Herbage yields Increased on the mounds previously occupied by shrubs, whereas production between shrubs was not affected by shrub removal. After four years there was sufficient shrub growth to prevent wind erosion, except on the cleared and grazed plot at the M. sedifolia site.