Doing more for the environment with lower inputs in pasture-based livestock systems: does this always lead to lower outputs?

David Chapman1 and Tony Parsons2

1 DairyNZ Ltd., PO Box 85066, Lincoln University, Lincoln, New Zealand. david.chapman@dairynz.co.nz
2 Institute of Agriculture and Environment, Massey University, PB11-222, Palmerston North, New Zealand. a.j.parsons@massey.ac.nz

Abstract
The rates of production growth achieved in the pasture-based livestock industries of New Zealand and Australia in the absence of environmental regulation may be curtailed as they enter a regulated future. Environmental limit-setting policy requires science that encompasses the multiple ways in which food can be produced, the multiple ensuing environmental emissions, and the long-term (50 to 100 year) relationships between these seemingly competing interests. In this paper, we use the rapid growth in food production achieved in the New Zealand dairy industry between 1990 and c. 2014 as an example of the emerging tensions between food production and environmental management. We describe an analysis, based on simulation, of the trade-offs between rates of food production and the long-term environmental impact of meat and dairy production systems which shows that it is not the change in land use from meat animals to dairy animals per se in New Zealand that has led to greater environmental impacts. Rather, it is the level of nitrogen (N) inputs associated with intensification of dairying that matters. The analysis shows that land use change from meat to dairy (with total nitrogen inputs of around 150 kg N/ha per year in the latter) can result in lower total emissions per hectare.  We also show that interactions between food production and environmental emissions across the full spectrum of options cannot be represented by a single relationship, despite the attractiveness of such a simplification.  The implications of this for science and policy are discussed.

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Southern Farming Systems Agriculture Victoria

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