Economics of Controlling Serrated Tussock in the Southeastern Australian Rangelands

Abstract

Serrated tussock (Nassella trichotoma), a grass native to South America, has been a major economic problem in the rangelands of southeastern Australia since 1950. It currently infests 680,000 ha in southeastern New South Wales, drastically reducing animal production. Controlling serrated tussock was profitable in most situations favourable for pasture improvement but only marginally profitable or unprofitable in areas with low to moderate soil fertility/rainfall indices. Internal rates of return ranged between 49.1% and 7.5% and the benefit-cost ratios between 1.83:1 and 0.88:1. Public intervention was considered to be necessary to expedite control in areas less favorable for pasture improvement. Public rates of return (273.1% to 132.7%) and benefit-cost ratios (32.3:1 to 11.2:1) to control were very high under a system of subsidized finance to private landholders. Various forms of potential public intervention were discussed.