The profitability of wool production after surface application of lime and superphosphate on acid soils

Soil acidity is one of the major farm management problems on the Southern Tablelands of NSW. Soil acidity occurs naturally and yet some agricultural practices exacerbate the process through nitrification, leaching, removal of produce and accumulation of organic matter in the soil. A grazing experiment was conducted between 1999 and 2008 near Sutton, NSW, to assess the impact of various combinations of lime and superphosphate application, and stocking rates, on the profitability and sustainability of wool production on the Southern Tablelands. The profitability of 15 alternative experimental treatments was assessed using the discounted cash flow analysis method for a Merino wether enterprise. The results revealed that the highest net present value was generated by a low input system involving un-limed soil, the lower superphosphate rate and the lowest stocking rate. We conclude that with current input and commodity prices, wool producers with a Merino wether enterprise will be unlikely to use lime to ameliorate acid soils, implying that soil resources will be exploited unless there are favourable inputs and commodity prices or policy intervention.