Central dieback of the dryland bunchgrass Eragrostis curvula (weeping lovegrass) re-examined: The experimental clearance of tussock centres

Abstract

Experiments were conducted to investigate: (1) tiller recruitment within the interior of Eragrostis curvula tussocks, with and without litter removal; and (2) effects of moderate defoliation on tiller recruitment within the interior of the clump. Tiller recruitment within the interior of non-defoliated plants was significantly (p<0·01) increased by litter removal. When field-grown plants were defoliated, the tillering rate was greater (p<0·01) in plants with litter retained than those with litter removed 91 days after defoliation. When the greenhouse-grown plants were defoliated, tiller recruitment was greater (p<0·05) in plants with litter retained than those with litter removed during the first 13 weeks after defoliation. Tillering in the non-defoliated plants was less (p<0·05) than in defoliated plants with litter retained. Litter removal or moderate defoliation stimulated basal tillering by opening up the canopy and providing more light available to the basal buds. Therefore, the central dieback is not simply a natural consequence of tillering pattern; resource depletion within the interior may be a contributing factor to this phenomenon.