Cost‐effective regulation of nonpoint emissions from pastoral agriculture: a stochastic analysis

Abstract

Nutrient emissions from pastoral agriculture are a global cause of declining water quality. Their management is complicated through variability arising from climate and soil influences. This paper compares the implications of input-based policies and direct restrictions on leaching to achieve 10 and 20 per cent reductions in nitrogen (N) load, in the context of pasture-based New Zealand dairy farms. The most important mitigation practices on these farms are de-intensification (involving reductions in N fertiliser application and stocking rate) and the application of nitrification inhibitors. A stylised conceptual model, incorporating both sources of variability, is used to identify the implications of alternative policies. Direct restriction of estimated N leaching is the most cost-effective policy to reduce N leaching by 10 and 20 per cent. These results indicate the general insufficiency of input-based mechanisms for water quality improvement, given the low correlation between input use and leaching, possible substitution with unrestricted inputs and their failure to motivate the use of mitigation strategies. Additionally, model output indicates that inherent variability in water quality, mainly due to climate influences, can dominate the benefits of regulatory action in any given year.

Review of Mathematical Programming Applications in Water Resource Management Under Uncertainty

“…urban land use, agriculture, forestry, eutrophication) [52]. Point and non-point sources of pollution are often regarded as controllable [139]); however, other factors, such as the weather and climate, can also impact water quality [50]. On a global scale, water quality can be assessed using measures, such as the proportion of the population with sustainable access to an improved water source [190].…”

Economic perspectives on nitrogen in farming systems: managing trade-offs between production, risk and the environment

“…There have been many studies to identify efficient strategies for reducing external costs from nitrogen application (e.g., Vatn et al 1997;Ribaudo et al 2001;Fröschl et al 2008), including studies of the optimal spatial allocation of abatement measures within a region or catchment (Doole and Romero 2014;Konrad et al 2014). On a larger spatial scale, there has been work on the design of systems for internationally coordinated pollution abatement for countries that share an affected water body, such as the countries around the Baltic Sea (Grem 2001;Hasler et al 2014).…”