New Zealand communities are seeking improved water quality. Applying New Zealand’s legislative framework, policy decisions to achieve these improvements must take account of a range of factors, including the sources of contaminants, and the economic implications of policy changes for resource users such as farmers. This paper outlines key components of agricultural information being used to underpin policy decision-making in the Ruamāhanga River Catchment, and evaluates the economic impacts on farming of one potential policy scenario to achieve improved water quality.
Twelve representative farms are used in the evaluation. Based on this, 24% of the nitrogen load entering the river from livestock agriculture is from dairying, 40% from sheep and beef breeding farms, and 36% from sheep and beef finishing farms. Reducing the nitrogen load in the river from the current levels of 0.64 to 0.53mg/L, requires livestock farmers in the catchment to reduce nitrogen discharges by an estimated 700T of nitrogen per year. Such a water quality target can be achieved if improved farm management practices are adopted, and provided that other human-induced sources of contaminant are also reduced. The costs of the farm management changes required could reduce their contribution to the district GDP by over 10%.
TG Parminter, 2017. Impacts of water policies on New Zealand livestock agriculture and the Ruamāhanga Catchment, Proceedings of the 21st International Farm Management Congress, vol 1, article 24.