Has the eco-efficiency of sheep and beef farms changed in the last 20 years?

Abstract

It is timely, with farming within biophysical limits as an emerging feature of the future operating environment for the sector, to explore whether the substantial productivity gains seen in the sheep and beef sector over the last 20 years translate into improved ecoefficiency and a reduction in the sector's environmental footprint. In this paper the changes in the relationship between inputs (e.g., livestock numbers, nutrients) and outputs (e.g., meat and fibre, greenhouse gas (GHG) emissions, nitrate) of the MAF Sheep and Beef Farm Monitoring models that cover hard hill country (Gisborne and Central North Island) and easy hill finishing (Manawatu) over the last 20 years were explored using the Overseer nutrient budget model. For the hard hill country extensive sheep and beef farm operation, the productivity gains made since 1989/90 translate into significant eco-efficiency gains, including a 47% increase in saleable product/ha (107 to 167 kg per ha), 21% reduction in nitrate leaching per kg of saleable product (0.065 to 0.054 kg N per kg animal product) and 40% reduction in the GHG emissions per kg of saleable product (27 to 19.2 kg CO2-e per kg animal product). The improvements have come through increased meat production. In contrast, the contribution from wool has been unchanged since 1989/90. These eco-efficiency gains, however, did not extend to include an overall reduction in N leaching or GHG emissions per hectare. In the easy hill finishing operation, where the MAF model farm size more than doubled over the last 20 years, there was little change in the eco-efficiency, but again also little change in total emissions. As we move to an operating environment where there are limits on emissions to the environment, understanding how to quantify eco-efficiency and monitor changes in this performance indicator becomes more than just an academic exercise. Keywords: Sheep and beef, eco-efficiency, meat and fibre production, N leaching, hill country