Impacts of rehabilitating degraded lands on soil health, pastures, runoff, erosion, nutrient and sediment movement. Part III: Economic analysis of rehabilitation techniques in the Burdekin River catchment to improve water quality flowing from grazing lands onto the Great Barrier Reef.

Poor grazing land condition reduces the productivity of grazing enterprises and has been linked to increased sediment loads entering the Great Barrier Reef Lagoon. There are several methods for rehabilitating degraded lands with varying levels of investment. The subsequent environmental and economic outcomes have previously been largely unquantified. This document assesses the potential economic impact of the rehabilitation treatments in the Burdekin Catchment for the project RRRD.024 – ‘Quantifying the impacts of rehabilitating degraded lands on soil health, pastures, runoff, erosion, nutrient and sediment movement’. Three mechanical intervention treatments and a control (no treatment) were evaluated on loamy alluvial soils at Spyglass Research Facility. These were: deep ripping, chisel ploughing and crocodile seeding. All treatments were seeded. Treatments varied in cost on a per hectare basis with deep ripping requiring $260.85 ha-1, chisel ploughing $210.85 ha-1, and crocodile seeding was least cost requiring $150.85 ha-1. Treatments also varied in benefits, particularly pasture yield and subsequent potential carrying capacity. From highest to lowest the potential average carrying capacity was deep ripping, chisel ploughing and crocodile seeding, with 25.3 AE 100 ha-1, 20.5 AE 100 ha-1 and 13.4 AE 100 ha-1, respectively. The control averaged 7.9 AE 100 ha-1. Despite apparent differences in costs and subsequent benefits, each treatment returned very similar economic results, particularly as measured by the internal rate of return. The internal rate of return (IRR) of chisel ploughing was highest (4.55%), followed by crocodile seeding (4.37%) and lastly, deep ripping (4.36%). This suggests that while spending more money and performing higher intervention might increase productivity the most, it does not necessary return more on a dollar for dollar basis. Despite positive IRRs, none of the treatments returned a positive net present value at the default parameters, suggesting funds could be better used elsewhere. It is recommended that producers investigate their eligibility for funding programs (such as Catchment organisations or Land Care) which assists with upfront costs of rehabilitation of degraded lands. This will allow producers to reduce losses and provide public benefits in the form of reduced sediment and nutrient runoff.